-<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>AltOS</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="book"><div class="titlepage"><div><div><h1 class="title"><a name="idm6266992"></a>AltOS</h1></div><div><h2 class="subtitle">Altos Metrum Operating System</h2></div><div><div class="author"><h3 class="author"><span class="firstname">Keith</span> <span class="surname">Packard</span></h3></div></div><div><p class="copyright">Copyright © 2010 Keith Packard</p></div><div><div class="legalnotice"><a name="idp48003248"></a><p>
- This document is released under the terms of the
- <a class="ulink" href="http://creativecommons.org/licenses/by-sa/3.0/" target="_top">
- Creative Commons ShareAlike 3.0
- </a>
- license.
- </p></div></div><div><div class="revhistory"><table style="border-style:solid; width:100%;" summary="Revision History"><tr><th align="left" valign="top" colspan="2"><b>Revision History</b></th></tr><tr><td align="left">Revision 1.1</td><td align="left">05 November 2012</td></tr><tr><td align="left" colspan="2">Portable version</td></tr><tr><td align="left">Revision 0.1</td><td align="left">22 November 2010</td></tr><tr><td align="left" colspan="2">Initial content</td></tr></table></div></div></div><hr></div><div class="toc"><p><b>Table of Contents</b></p><dl class="toc"><dt><span class="chapter"><a href="#idp47883536">1. Overview</a></span></dt><dt><span class="chapter"><a href="#idp48965696">2. AltOS Porting Layer</a></span></dt><dd><dl><dt><span class="section"><a href="#idp48967200">1. Low-level CPU operations</a></span></dt><dd><dl><dt><span class="section"><a href="#idp48968432">1.1. ao_arch_block_interrupts/ao_arch_release_interrupts</a></span></dt><dt><span class="section"><a href="#idp48970480">1.2. ao_arch_save_regs, ao_arch_save_stack,
- ao_arch_restore_stack</a></span></dt><dt><span class="section"><a href="#idp53013312">1.3. ao_arch_wait_interupt</a></span></dt></dl></dd><dt><span class="section"><a href="#idp53015856">2. GPIO operations</a></span></dt><dd><dl><dt><span class="section"><a href="#idp53017024">2.1. GPIO setup</a></span></dt><dt><span class="section"><a href="#idp53026240">2.2. Reading and writing GPIO pins</a></span></dt></dl></dd></dl></dd><dt><span class="chapter"><a href="#idp47889728">3. Programming the 8051 with SDCC</a></span></dt><dd><dl><dt><span class="section"><a href="#idp47891824">1. 8051 memory spaces</a></span></dt><dd><dl><dt><span class="section"><a href="#idp47893760">1.1. __data</a></span></dt><dt><span class="section"><a href="#idp47895936">1.2. __idata</a></span></dt><dt><span class="section"><a href="#idp47897376">1.3. __xdata</a></span></dt><dt><span class="section"><a href="#idp47898784">1.4. __pdata</a></span></dt><dt><span class="section"><a href="#idp47900288">1.5. __code</a></span></dt><dt><span class="section"><a href="#idp47901728">1.6. __bit</a></span></dt><dt><span class="section"><a href="#idp47903232">1.7. __sfr, __sfr16, __sfr32, __sbit</a></span></dt></dl></dd><dt><span class="section"><a href="#idp47904768">2. Function calls on the 8051</a></span></dt><dd><dl><dt><span class="section"><a href="#idp47906240">2.1. __reentrant functions</a></span></dt><dt><span class="section"><a href="#idp47908432">2.2. Non __reentrant functions</a></span></dt><dt><span class="section"><a href="#idp47910576">2.3. __interrupt functions</a></span></dt><dt><span class="section"><a href="#idp47912144">2.4. __critical functions and statements</a></span></dt></dl></dd></dl></dd><dt><span class="chapter"><a href="#idp47914208">4. Task functions</a></span></dt><dd><dl><dt><span class="section"><a href="#idp47915264">1. ao_add_task</a></span></dt><dt><span class="section"><a href="#idp47917520">2. ao_exit</a></span></dt><dt><span class="section"><a href="#idp53850448">3. ao_sleep</a></span></dt><dt><span class="section"><a href="#idp53854048">4. ao_wakeup</a></span></dt><dt><span class="section"><a href="#idp53857040">5. ao_alarm</a></span></dt><dt><span class="section"><a href="#idp53860224">6. ao_start_scheduler</a></span></dt><dt><span class="section"><a href="#idp53862192">7. ao_clock_init</a></span></dt></dl></dd><dt><span class="chapter"><a href="#idp53864160">5. Timer Functions</a></span></dt><dd><dl><dt><span class="section"><a href="#idp53865664">1. ao_time</a></span></dt><dt><span class="section"><a href="#idp53867648">2. ao_delay</a></span></dt><dt><span class="section"><a href="#idp53869488">3. ao_timer_set_adc_interval</a></span></dt><dt><span class="section"><a href="#idp53871536">4. ao_timer_init</a></span></dt></dl></dd><dt><span class="chapter"><a href="#idp53873728">6. AltOS Mutexes</a></span></dt><dd><dl><dt><span class="section"><a href="#idp53875600">1. ao_mutex_get</a></span></dt><dt><span class="section"><a href="#idp53877440">2. ao_mutex_put</a></span></dt></dl></dd><dt><span class="chapter"><a href="#idp53879408">7. DMA engine</a></span></dt><dd><dl><dt><span class="section"><a href="#idp53882848">1. CC1111 DMA Engine</a></span></dt><dd><dl><dt><span class="section"><a href="#idp53883520">1.1. ao_dma_alloc</a></span></dt><dt><span class="section"><a href="#idp53885696">1.2. ao_dma_set_transfer</a></span></dt><dt><span class="section"><a href="#idp53887968">1.3. ao_dma_start</a></span></dt><dt><span class="section"><a href="#idp53889984">1.4. ao_dma_trigger</a></span></dt><dt><span class="section"><a href="#idp53891824">1.5. ao_dma_abort</a></span></dt></dl></dd><dt><span class="section"><a href="#idp53893968">2. STM32L DMA Engine</a></span></dt><dd><dl><dt><span class="section"><a href="#idp53894640">2.1. ao_dma_alloc</a></span></dt><dt><span class="section"><a href="#idp53896480">2.2. ao_dma_set_transfer</a></span></dt><dt><span class="section"><a href="#idp53898736">2.3. ao_dma_set_isr</a></span></dt><dt><span class="section"><a href="#idp53900816">2.4. ao_dma_start</a></span></dt><dt><span class="section"><a href="#idp53903120">2.5. ao_dma_done_transfer</a></span></dt><dt><span class="section"><a href="#idp53905104">2.6. ao_dma_abort</a></span></dt></dl></dd></dl></dd><dt><span class="chapter"><a href="#idp53907376">8. Stdio interface</a></span></dt><dd><dl><dt><span class="section"><a href="#idp53908880">1. putchar</a></span></dt><dt><span class="section"><a href="#idp53910768">2. getchar</a></span></dt><dt><span class="section"><a href="#idp53912864">3. flush</a></span></dt><dt><span class="section"><a href="#idp53914896">4. ao_add_stdio</a></span></dt></dl></dd><dt><span class="chapter"><a href="#idp53918848">9. Command line interface</a></span></dt><dd><dl><dt><span class="section"><a href="#idp53920256">1. ao_cmd_register</a></span></dt><dt><span class="section"><a href="#idp53928816">2. ao_cmd_lex</a></span></dt><dt><span class="section"><a href="#idp53930896">3. ao_cmd_put16</a></span></dt><dt><span class="section"><a href="#idp53932736">4. ao_cmd_put8</a></span></dt><dt><span class="section"><a href="#idp53934624">5. ao_cmd_white</a></span></dt><dt><span class="section"><a href="#idp53936688">6. ao_cmd_hex</a></span></dt><dt><span class="section"><a href="#idp53938736">7. ao_cmd_decimal</a></span></dt><dt><span class="section"><a href="#idp53940832">8. ao_match_word</a></span></dt><dt><span class="section"><a href="#idp53942912">9. ao_cmd_init</a></span></dt></dl></dd><dt><span class="chapter"><a href="#idp53945136">10. USB target device</a></span></dt><dd><dl><dt><span class="section"><a href="#idp53947360">1. ao_usb_flush</a></span></dt><dt><span class="section"><a href="#idp53949504">2. ao_usb_putchar</a></span></dt><dt><span class="section"><a href="#idp53951680">3. ao_usb_pollchar</a></span></dt><dt><span class="section"><a href="#idp53953824">4. ao_usb_getchar</a></span></dt><dt><span class="section"><a href="#idp53955840">5. ao_usb_disable</a></span></dt><dt><span class="section"><a href="#idp53958672">6. ao_usb_enable</a></span></dt><dt><span class="section"><a href="#idp53960784">7. ao_usb_init</a></span></dt></dl></dd><dt><span class="chapter"><a href="#idp53963008">11. Serial peripherals</a></span></dt><dd><dl><dt><span class="section"><a href="#idp53965024">1. ao_serial_getchar</a></span></dt><dt><span class="section"><a href="#idp53967056">2. ao_serial_putchar</a></span></dt><dt><span class="section"><a href="#idp53969024">3. ao_serial_drain</a></span></dt><dt><span class="section"><a href="#idp53971024">4. ao_serial_set_speed</a></span></dt><dt><span class="section"><a href="#idp53973056">5. ao_serial_init</a></span></dt></dl></dd><dt><span class="chapter"><a href="#idp53975248">12. CC1111 Radio peripheral</a></span></dt><dd><dl><dt><span class="section"><a href="#idp53975920">1. Radio Introduction</a></span></dt><dt><span class="section"><a href="#idp53983040">2. ao_radio_set_telemetry</a></span></dt><dt><span class="section"><a href="#idp53985200">3. ao_radio_set_packet</a></span></dt><dt><span class="section"><a href="#idp53987360">4. ao_radio_set_rdf</a></span></dt><dt><span class="section"><a href="#idp53989600">5. ao_radio_idle</a></span></dt><dt><span class="section"><a href="#idp53991648">6. ao_radio_get</a></span></dt><dt><span class="section"><a href="#idp53993680">7. ao_radio_put</a></span></dt><dt><span class="section"><a href="#idp53995616">8. ao_radio_abort</a></span></dt><dt><span class="section"><a href="#idp53997680">9. Radio Telemetry</a></span></dt><dd><dl><dt><span class="section"><a href="#idp53998976">9.1. ao_radio_send</a></span></dt><dt><span class="section"><a href="#idp54001120">9.2. ao_radio_recv</a></span></dt></dl></dd><dt><span class="section"><a href="#idp54003504">10. Radio Direction Finding</a></span></dt><dd><dl><dt><span class="section"><a href="#idp54004656">10.1. ao_radio_rdf</a></span></dt></dl></dd><dt><span class="section"><a href="#idp54006800">11. Radio Packet Mode</a></span></dt><dd><dl><dt><span class="section"><a href="#idp54008112">11.1. ao_packet_putchar</a></span></dt><dt><span class="section"><a href="#idp54010288">11.2. ao_packet_pollchar</a></span></dt><dt><span class="section"><a href="#idp54012368">11.3. ao_packet_slave_start</a></span></dt><dt><span class="section"><a href="#idp54014320">11.4. ao_packet_slave_stop</a></span></dt><dt><span class="section"><a href="#idp54016160">11.5. ao_packet_slave_init</a></span></dt><dt><span class="section"><a href="#idp54018192">11.6. ao_packet_master_init</a></span></dt></dl></dd></dl></dd></dl></div><div class="chapter"><div class="titlepage"><div><div><h1 class="title"><a name="idp47883536"></a>Chapter 1. Overview</h1></div></div></div><p>
- AltOS is a operating system built for a variety of
- microcontrollers used in Altus Metrum devices. It has a simple
- porting layer for each CPU while providing a convenient
- operating enviroment for the developer. AltOS currently
- supports three different CPUs:
- </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
- STM32L series from ST Microelectronics. This ARM Cortex-M3
- based microcontroller offers low power consumption and a
- wide variety of built-in peripherals. Altus Metrum uses
- this in the TeleMega, MegaDongle and TeleLCO projects.
- </p></li><li class="listitem"><p>
- CC1111 from Texas Instruments. This device includes a
- fabulous 10mW digital RF transceiver along with an
- 8051-compatible processor core and a range of
- peripherals. This is used in the TeleMetrum, TeleMini,
- TeleDongle and TeleFire projects which share the need for
- a small microcontroller and an RF interface.
- </p></li><li class="listitem"><p>
- ATmega32U4 from Atmel. This 8-bit AVR microcontroller is
- one of the many used to create Arduino boards. The 32U4
- includes a USB interface, making it easy to connect to
- other computers. Altus Metrum used this in prototypes of
- the TeleScience and TelePyro boards; those have been
- switched to the STM32L which is more capable and cheaper.
- </p></li></ul></div><p>
- Among the features of AltOS are:
- </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>Multi-tasking. While microcontrollers often don't
- provide separate address spaces, it's often easier to write
- code that operates in separate threads instead of tying
- everything into one giant event loop.
- </p></li><li class="listitem"><p>Non-preemptive. This increases latency for thread
- switching but reduces the number of places where context
- switching can occur. It also simplifies the operating system
- design somewhat. Nothing in the target system (rocket flight
- control) has tight timing requirements, and so this seems like
- a reasonable compromise.
- </p></li><li class="listitem"><p>Sleep/wakeup scheduling. Taken directly from ancient
- Unix designs, these two provide the fundemental scheduling
- primitive within AltOS.
- </p></li><li class="listitem"><p>Mutexes. As a locking primitive, mutexes are easier to
- use than semaphores, at least in my experience.
- </p></li><li class="listitem"><p>Timers. Tasks can set an alarm which will abort any
- pending sleep, allowing operations to time-out instead of
- blocking forever.
- </p></li></ul></div><p>
- </p><p>
- The device drivers and other subsystems in AltOS are
- conventionally enabled by invoking their _init() function from
- the 'main' function before that calls
- ao_start_scheduler(). These functions initialize the pin
- assignments, add various commands to the command processor and
- may add tasks to the scheduler to handle the device. A typical
- main program, thus, looks like:
- </p><pre class="programlisting">
- void
- main(void)
- {
- ao_clock_init();
+<!DOCTYPE html>
+<html lang="en">
+<head>
+<meta charset="UTF-8">
+<meta http-equiv="X-UA-Compatible" content="IE=edge">
+<meta name="viewport" content="width=device-width, initial-scale=1.0">
+<meta name="generator" content="Asciidoctor 2.0.10">
+<meta name="author" content="Keith Packard">
+<title>AltOS</title>
+<link rel="stylesheet" href="./am.css">
+</head>
+<body class="book">
+<div id="header">
+<h1>AltOS</h1>
+<div class="details">
+<span id="author" class="author">Keith Packard</span><br>
+<span id="email" class="email"><a href="mailto:keithp@keithp.com">keithp@keithp.com</a></span><br>
+<span id="revdate">29 Sep 2020</span>
+</div>
+<div id="toc" class="toc">
+<div id="toctitle">Table of Contents</div>
+<ul class="sectlevel1">
+<li><a href="#_license">License</a></li>
+<li><a href="#_overview">1. Overview</a></li>
+<li><a href="#_altos_porting_layer">2. AltOS Porting Layer</a>
+<ul class="sectlevel2">
+<li><a href="#_low_level_cpu_operations">2.1. Low-level CPU operations</a></li>
+<li><a href="#_gpio_operations">2.2. GPIO operations</a></li>
+<li><a href="#_8051_memory_spaces">2.3. 8051 memory spaces</a></li>
+<li><a href="#_function_calls_on_the_8051">2.4. Function calls on the 8051</a></li>
+</ul>
+</li>
+<li><a href="#_task_functions">3. Task functions</a>
+<ul class="sectlevel2">
+<li><a href="#_ao_add_task">3.1. ao_add_task</a></li>
+<li><a href="#_ao_exit">3.2. ao_exit</a></li>
+<li><a href="#_ao_sleep">3.3. ao_sleep</a></li>
+<li><a href="#_ao_wakeup">3.4. ao_wakeup</a></li>
+<li><a href="#_ao_alarm">3.5. ao_alarm</a></li>
+<li><a href="#_ao_start_scheduler">3.6. ao_start_scheduler</a></li>
+<li><a href="#_ao_clock_init">3.7. ao_clock_init</a></li>
+</ul>
+</li>
+<li><a href="#_timer_functions">4. Timer Functions</a>
+<ul class="sectlevel2">
+<li><a href="#_ao_time">4.1. ao_time</a></li>
+<li><a href="#_ao_delay">4.2. ao_delay</a></li>
+<li><a href="#_ao_timer_set_adc_interval">4.3. ao_timer_set_adc_interval</a></li>
+<li><a href="#_ao_timer_init">4.4. ao_timer_init</a></li>
+</ul>
+</li>
+<li><a href="#_altos_mutexes">5. AltOS Mutexes</a>
+<ul class="sectlevel2">
+<li><a href="#_ao_mutex_get">5.1. ao_mutex_get</a></li>
+<li><a href="#_ao_mutex_put">5.2. ao_mutex_put</a></li>
+</ul>
+</li>
+<li><a href="#_dma_engine">6. DMA engine</a>
+<ul class="sectlevel2">
+<li><a href="#_cc1111_dma_engine">6.1. CC1111 DMA Engine</a></li>
+<li><a href="#_stm32l_dma_engine">6.2. STM32L DMA Engine</a></li>
+</ul>
+</li>
+<li><a href="#_stdio_interface">7. Stdio interface</a>
+<ul class="sectlevel2">
+<li><a href="#_putchar">7.1. putchar</a></li>
+<li><a href="#_getchar">7.2. getchar</a></li>
+<li><a href="#_flush">7.3. flush</a></li>
+<li><a href="#_ao_add_stdio">7.4. ao_add_stdio</a></li>
+</ul>
+</li>
+<li><a href="#_command_line_interface">8. Command line interface</a>
+<ul class="sectlevel2">
+<li><a href="#_ao_cmd_register">8.1. ao_cmd_register</a></li>
+<li><a href="#_ao_cmd_lex">8.2. ao_cmd_lex</a></li>
+<li><a href="#_ao_cmd_put16">8.3. ao_cmd_put16</a></li>
+<li><a href="#_ao_cmd_put8">8.4. ao_cmd_put8</a></li>
+<li><a href="#_ao_cmd_white">8.5. ao_cmd_white</a></li>
+<li><a href="#_ao_cmd_hex">8.6. ao_cmd_hex</a></li>
+<li><a href="#_ao_cmd_decimal">8.7. ao_cmd_decimal</a></li>
+<li><a href="#_ao_match_word">8.8. ao_match_word</a></li>
+<li><a href="#_ao_cmd_init">8.9. ao_cmd_init</a></li>
+</ul>
+</li>
+<li><a href="#_usb_target_device">9. USB target device</a>
+<ul class="sectlevel2">
+<li><a href="#_ao_usb_flush">9.1. ao_usb_flush</a></li>
+<li><a href="#_ao_usb_putchar">9.2. ao_usb_putchar</a></li>
+<li><a href="#_ao_usb_pollchar">9.3. ao_usb_pollchar</a></li>
+<li><a href="#_ao_usb_getchar">9.4. ao_usb_getchar</a></li>
+<li><a href="#_ao_usb_disable">9.5. ao_usb_disable</a></li>
+<li><a href="#_ao_usb_enable">9.6. ao_usb_enable</a></li>
+<li><a href="#_ao_usb_init">9.7. ao_usb_init</a></li>
+</ul>
+</li>
+<li><a href="#_serial_peripherals">10. Serial peripherals</a>
+<ul class="sectlevel2">
+<li><a href="#_ao_serial_getchar">10.1. ao_serial_getchar</a></li>
+<li><a href="#_ao_serial_putchar">10.2. ao_serial_putchar</a></li>
+<li><a href="#_ao_serial_drain">10.3. ao_serial_drain</a></li>
+<li><a href="#_ao_serial_set_speed">10.4. ao_serial_set_speed</a></li>
+<li><a href="#_ao_serial_init">10.5. ao_serial_init</a></li>
+</ul>
+</li>
+<li><a href="#_cc1111cc1120cc1200_radio_peripheral">11. CC1111/CC1120/CC1200 Radio peripheral</a>
+<ul class="sectlevel2">
+<li><a href="#_radio_introduction">11.1. Radio Introduction</a></li>
+<li><a href="#_ao_radio_set_telemetry">11.2. ao_radio_set_telemetry</a></li>
+<li><a href="#_ao_radio_set_packet">11.3. ao_radio_set_packet</a></li>
+<li><a href="#_ao_radio_set_rdf">11.4. ao_radio_set_rdf</a></li>
+<li><a href="#_ao_radio_idle">11.5. ao_radio_idle</a></li>
+<li><a href="#_ao_radio_get">11.6. ao_radio_get</a></li>
+<li><a href="#_ao_radio_put">11.7. ao_radio_put</a></li>
+<li><a href="#_ao_radio_abort">11.8. ao_radio_abort</a></li>
+<li><a href="#_radio_telemetry">11.9. Radio Telemetry</a></li>
+<li><a href="#_radio_direction_finding">11.10. Radio Direction Finding</a></li>
+<li><a href="#_radio_packet_mode">11.11. Radio Packet Mode</a></li>
+</ul>
+</li>
+</ul>
+</div>
+</div>
+<div id="content">
+<div id="preamble">
+<div class="sectionbody">
+<div id="logo" class="imageblock">
+<div class="content">
+<a class="image" href="https://altusmetrum.org"><img src="altusmetrum-oneline.svg" alt="Altus Metrum"></a>
+</div>
+</div>
+</div>
+</div>
+<div class="sect1">
+<h2 id="_license">License</h2>
+<div class="sectionbody">
+<div class="paragraph">
+<p>Copyright © 2018 Bdale Garbee and Keith Packard</p>
+</div>
+<div class="paragraph">
+<p>This document is released under the terms of the <a href="http://creativecommons.org/licenses/by-sa/3.0/">Creative Commons ShareAlike 3.0 License</a></p>
+</div>
+</div>
+</div>
+<div class="sect1">
+<h2 id="_overview">1. Overview</h2>
+<div class="sectionbody">
+<div class="paragraph">
+<p>AltOS is a operating system built for a variety of
+microcontrollers used in Altus Metrum devices. It has a simple
+porting layer for each CPU while providing a convenient
+operating enviroment for the developer. AltOS currently
+supports three different CPUs:</p>
+</div>
+<div class="ulist">
+<ul>
+<li>
+<p>STM32L series from ST Microelectronics. This ARM Cortex-M3
+based microcontroller offers low power consumption and a
+wide variety of built-in peripherals. Altus Metrum uses this
+in the TeleMega, MegaDongle and TeleLCO projects.</p>
+</li>
+<li>
+<p>CC1111 from Texas Instruments. This device includes a
+fabulous 10mW digital RF transceiver along with an
+8051-compatible processor core and a range of
+peripherals. This is used in the TeleMetrum, TeleMini,
+TeleDongle and TeleFire projects which share the need for a
+small microcontroller and an RF interface.</p>
+</li>
+<li>
+<p>ATmega32U4 from Atmel. This 8-bit AVR microcontroller is one
+of the many used to create Arduino boards. The 32U4 includes
+a USB interface, making it easy to connect to other
+computers. Altus Metrum used this in prototypes of the
+TeleScience and TelePyro boards; those have been switched to
+the STM32L which is more capable and cheaper.</p>
+</li>
+</ul>
+</div>
+<div class="paragraph">
+<p>Among the features of AltOS are:</p>
+</div>
+<div class="ulist">
+<ul>
+<li>
+<p>Multi-tasking. While microcontrollers often don’t
+provide separate address spaces, it’s often easier to write
+code that operates in separate threads instead of tying
+everything into one giant event loop.</p>
+</li>
+<li>
+<p>Non-preemptive. This increases latency for thread
+switching but reduces the number of places where context
+switching can occur. It also simplifies the operating system
+design somewhat. Nothing in the target system (rocket flight
+control) has tight timing requirements, and so this seems like
+a reasonable compromise.</p>
+</li>
+<li>
+<p>Sleep/wakeup scheduling. Taken directly from ancient
+Unix designs, these two provide the fundemental scheduling
+primitive within AltOS.</p>
+</li>
+<li>
+<p>Mutexes. As a locking primitive, mutexes are easier to
+use than semaphores, at least in my experience.</p>
+</li>
+<li>
+<p>Timers. Tasks can set an alarm which will abort any
+pending sleep, allowing operations to time-out instead of
+blocking forever.</p>
+</li>
+</ul>
+</div>
+<div class="paragraph">
+<p>The device drivers and other subsystems in AltOS are
+conventionally enabled by invoking their _init() function from
+the 'main' function before that calls
+ao_start_scheduler(). These functions initialize the pin
+assignments, add various commands to the command processor and
+may add tasks to the scheduler to handle the device. A typical
+main program, thus, looks like:</p>
+</div>
+<div class="literalblock">
+<div class="content">
+<pre>void
+main(void)
+{
+ ao_clock_init();
- /* Turn on the LED until the system is stable */
- ao_led_init(LEDS_AVAILABLE);
- ao_led_on(AO_LED_RED);
- ao_timer_init();
- ao_cmd_init();
- ao_usb_init();
- ao_monitor_init(AO_LED_GREEN, TRUE);
- ao_rssi_init(AO_LED_RED);
- ao_radio_init();
- ao_packet_slave_init();
- ao_packet_master_init();
- #if HAS_DBG
- ao_dbg_init();
- #endif
- ao_config_init();
- ao_start_scheduler();
- }
- </pre><p>
- As you can see, a long sequence of subsystems are initialized
- and then the scheduler is started.
- </p></div><div class="chapter"><div class="titlepage"><div><div><h1 class="title"><a name="idp48965696"></a>Chapter 2. AltOS Porting Layer</h1></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl class="toc"><dt><span class="section"><a href="#idp48967200">1. Low-level CPU operations</a></span></dt><dd><dl><dt><span class="section"><a href="#idp48968432">1.1. ao_arch_block_interrupts/ao_arch_release_interrupts</a></span></dt><dt><span class="section"><a href="#idp48970480">1.2. ao_arch_save_regs, ao_arch_save_stack,
- ao_arch_restore_stack</a></span></dt><dt><span class="section"><a href="#idp53013312">1.3. ao_arch_wait_interupt</a></span></dt></dl></dd><dt><span class="section"><a href="#idp53015856">2. GPIO operations</a></span></dt><dd><dl><dt><span class="section"><a href="#idp53017024">2.1. GPIO setup</a></span></dt><dt><span class="section"><a href="#idp53026240">2.2. Reading and writing GPIO pins</a></span></dt></dl></dd></dl></div><p>
- AltOS provides a CPU-independent interface to various common
- microcontroller subsystems, including GPIO pins, interrupts,
- SPI, I2C, USB and asynchronous serial interfaces. By making
- these CPU-independent, device drivers, generic OS and
- application code can all be written that work on any supported
- CPU. Many of the architecture abstraction interfaces are
- prefixed with ao_arch.
- </p><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp48967200"></a>1. Low-level CPU operations</h2></div></div></div><p>
- These primitive operations provide the abstraction needed to
- run the multi-tasking framework while providing reliable
- interrupt delivery.
- </p><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp48968432"></a>1.1. ao_arch_block_interrupts/ao_arch_release_interrupts</h3></div></div></div><pre class="programlisting">
- static inline void
- ao_arch_block_interrupts(void);
-
- static inline void
- ao_arch_release_interrupts(void);
- </pre><p>
- These disable/enable interrupt delivery, they may not
- discard any interrupts. Use these for sections of code that
- must be atomic with respect to any code run from an
- interrupt handler.
- </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp48970480"></a>1.2. ao_arch_save_regs, ao_arch_save_stack,
- ao_arch_restore_stack</h3></div></div></div><pre class="programlisting">
- static inline void
- ao_arch_save_regs(void);
+ /* Turn on the LED until the system is stable */
+ ao_led_init(LEDS_AVAILABLE);
+ ao_led_on(AO_LED_RED);
+ ao_timer_init();
+ ao_cmd_init();
+ ao_usb_init();
+ ao_monitor_init(AO_LED_GREEN, TRUE);
+ ao_rssi_init(AO_LED_RED);
+ ao_radio_init();
+ ao_packet_slave_init();
+ ao_packet_master_init();
+#if HAS_DBG
+ ao_dbg_init();
+#endif
+ ao_config_init();
+ ao_start_scheduler();
+}</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>As you can see, a long sequence of subsystems are initialized
+and then the scheduler is started.</p>
+</div>
+</div>
+</div>
+<div class="sect1">
+<h2 id="_altos_porting_layer">2. AltOS Porting Layer</h2>
+<div class="sectionbody">
+<div class="paragraph">
+<p>AltOS provides a CPU-independent interface to various common
+microcontroller subsystems, including GPIO pins, interrupts,
+SPI, I2C, USB and asynchronous serial interfaces. By making
+these CPU-independent, device drivers, generic OS and
+application code can all be written that work on any supported
+CPU. Many of the architecture abstraction interfaces are
+prefixed with ao_arch.</p>
+</div>
+<div class="sect2">
+<h3 id="_low_level_cpu_operations">2.1. Low-level CPU operations</h3>
+<div class="paragraph">
+<p>These primitive operations provide the abstraction needed to
+run the multi-tasking framework while providing reliable
+interrupt delivery.</p>
+</div>
+<div class="sect3">
+<h4 id="_ao_arch_block_interruptsao_arch_release_interrupts">2.1.1. ao_arch_block_interrupts/ao_arch_release_interrupts</h4>
+<div class="literalblock">
+<div class="content">
+<pre>static inline void
+ao_arch_block_interrupts(void);
- static inline void
- ao_arch_save_stack(void);
+static inline void
+ao_arch_release_interrupts(void);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>These disable/enable interrupt delivery, they may not
+discard any interrupts. Use these for sections of code that
+must be atomic with respect to any code run from an
+interrupt handler.</p>
+</div>
+</div>
+<div class="sect3">
+<h4 id="_ao_arch_save_regs_ao_arch_save_stack_ao_arch_restore_stack">2.1.2. ao_arch_save_regs, ao_arch_save_stack, ao_arch_restore_stack</h4>
+<div class="literalblock">
+<div class="content">
+<pre>static inline void
+ao_arch_save_regs(void);
- static inline void
- ao_arch_restore_stack(void);
- </pre><p>
- These provide all of the support needed to switch between
- tasks.. ao_arch_save_regs must save all CPU registers to the
- current stack, including the interrupt enable
- state. ao_arch_save_stack records the current stack location
- in the current ao_task structure. ao_arch_restore_stack
- switches back to the saved stack, restores all registers and
- branches to the saved return address.
- </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp53013312"></a>1.3. ao_arch_wait_interupt</h3></div></div></div><pre class="programlisting">
- #define ao_arch_wait_interrupt()
- </pre><p>
- This stops the CPU, leaving clocks and interrupts
- enabled. When an interrupt is received, this must wake up
- and handle the interrupt. ao_arch_wait_interrupt is entered
- with interrupts disabled to ensure that there is no gap
- between determining that no task wants to run and idling the
- CPU. It must sleep the CPU, process interrupts and then
- disable interrupts again. If the CPU doesn't have any
- reduced power mode, this must at the least allow pending
- interrupts to be processed.
- </p></div></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53015856"></a>2. GPIO operations</h2></div></div></div><p>
- These functions provide an abstract interface to configure and
- manipulate GPIO pins.
- </p><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp53017024"></a>2.1. GPIO setup</h3></div></div></div><p>
- These macros may be invoked at system initialization time to
- configure pins as needed for system operation. One tricky
- aspect is that some chips provide direct access to specific
- GPIO pins while others only provide access to a whole
- register full of pins. To support this, the GPIO macros
- provide both port+bit and pin arguments. Simply define the
- arguments needed for the target platform and leave the
- others undefined.
- </p><div class="section"><div class="titlepage"><div><div><h4 class="title"><a name="idp53018864"></a>2.1.1. ao_enable_output</h4></div></div></div><pre class="programlisting">
- #define ao_enable_output(port, bit, pin, value)
- </pre><p>
- Set the specified port+bit (also called 'pin') for output,
- initializing to the specified value. The macro must avoid
- driving the pin with the opposite value if at all
- possible.
- </p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a name="idp53020896"></a>2.1.2. ao_enable_input</h4></div></div></div><pre class="programlisting">
- #define ao_enable_input(port, bit, mode)
- </pre><p>
- Sets the specified port/bit to be an input pin. 'mode' is
- a combination of one or more of the following. Note that
- some platforms may not support the desired mode. In that
- case, the value will not be defined so that the program
- will fail to compile.
- </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
- AO_EXTI_MODE_PULL_UP. Apply a pull-up to the pin; a
- disconnected pin will read as 1.
-</p></li><li class="listitem"><p>
- AO_EXTI_MODE_PULL_DOWN. Apply a pull-down to the pin;
- a disconnected pin will read as 0.
-</p></li><li class="listitem"><p>
- 0. Don't apply either a pull-up or pull-down. A
- disconnected pin will read an undetermined value.
-</p></li></ul></div><p>
- </p></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp53026240"></a>2.2. Reading and writing GPIO pins</h3></div></div></div><p>
- These macros read and write individual GPIO pins.
- </p><div class="section"><div class="titlepage"><div><div><h4 class="title"><a name="idp53027312"></a>2.2.1. ao_gpio_set</h4></div></div></div><pre class="programlisting">
- #define ao_gpio_set(port, bit, pin, value)
- </pre><p>
- Sets the specified port/bit or pin to the indicated value
- </p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a name="idp47887392"></a>2.2.2. ao_gpio_get</h4></div></div></div><pre class="programlisting">
- #define ao_gpio_get(port, bit, pin)
- </pre><p>
- Returns either 1 or 0 depending on whether the input to
- the pin is high or low.
- </p></div></div></div></div><div class="chapter"><div class="titlepage"><div><div><h1 class="title"><a name="idp47889728"></a>Chapter 3. Programming the 8051 with SDCC</h1></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl class="toc"><dt><span class="section"><a href="#idp47891824">1. 8051 memory spaces</a></span></dt><dd><dl><dt><span class="section"><a href="#idp47893760">1.1. __data</a></span></dt><dt><span class="section"><a href="#idp47895936">1.2. __idata</a></span></dt><dt><span class="section"><a href="#idp47897376">1.3. __xdata</a></span></dt><dt><span class="section"><a href="#idp47898784">1.4. __pdata</a></span></dt><dt><span class="section"><a href="#idp47900288">1.5. __code</a></span></dt><dt><span class="section"><a href="#idp47901728">1.6. __bit</a></span></dt><dt><span class="section"><a href="#idp47903232">1.7. __sfr, __sfr16, __sfr32, __sbit</a></span></dt></dl></dd><dt><span class="section"><a href="#idp47904768">2. Function calls on the 8051</a></span></dt><dd><dl><dt><span class="section"><a href="#idp47906240">2.1. __reentrant functions</a></span></dt><dt><span class="section"><a href="#idp47908432">2.2. Non __reentrant functions</a></span></dt><dt><span class="section"><a href="#idp47910576">2.3. __interrupt functions</a></span></dt><dt><span class="section"><a href="#idp47912144">2.4. __critical functions and statements</a></span></dt></dl></dd></dl></div><p>
- The 8051 is a primitive 8-bit processor, designed in the mists
- of time in as few transistors as possible. The architecture is
- highly irregular and includes several separate memory
- spaces. Furthermore, accessing stack variables is slow, and the
- stack itself is of limited size. While SDCC papers over the
- instruction set, it is not completely able to hide the memory
- architecture from the application designer.
- </p><p>
- When built on other architectures, the various SDCC-specific
- symbols are #defined as empty strings so they don't affect the compiler.
- </p><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp47891824"></a>1. 8051 memory spaces</h2></div></div></div><p>
- The __data/__xdata/__code memory spaces below were completely
- separate in the original 8051 design. In the cc1111, this
- isn't true—they all live in a single unified 64kB address
- space, and so it's possible to convert any address into a
- unique 16-bit address. SDCC doesn't know this, and so a
- 'global' address to SDCC consumes 3 bytes of memory, 1 byte as
- a tag indicating the memory space and 2 bytes of offset within
- that space. AltOS avoids these 3-byte addresses as much as
- possible; using them involves a function call per byte
- access. The result is that nearly every variable declaration
- is decorated with a memory space identifier which clutters the
- code but makes the resulting code far smaller and more
- efficient.
- </p><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp47893760"></a>1.1. __data</h3></div></div></div><p>
- The 8051 can directly address these 128 bytes of
- memory. This makes them precious so they should be
- reserved for frequently addressed values. Oh, just to
- confuse things further, the 8 general registers in the
- CPU are actually stored in this memory space. There are
- magic instructions to 'bank switch' among 4 banks of
- these registers located at 0x00 - 0x1F. AltOS uses only
- the first bank at 0x00 - 0x07, leaving the other 24
- bytes available for other data.
- </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp47895936"></a>1.2. __idata</h3></div></div></div><p>
- There are an additional 128 bytes of internal memory
- that share the same address space as __data but which
- cannot be directly addressed. The stack normally
- occupies this space and so AltOS doesn't place any
- static storage here.
- </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp47897376"></a>1.3. __xdata</h3></div></div></div><p>
- This is additional general memory accessed through a
- single 16-bit address register. The CC1111F32 has 32kB
- of memory available here. Most program data should live
- in this memory space.
- </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp47898784"></a>1.4. __pdata</h3></div></div></div><p>
- This is an alias for the first 256 bytes of __xdata
- memory, but uses a shorter addressing mode with
- single global 8-bit value for the high 8 bits of the
- address and any of several 8-bit registers for the low 8
- bits. AltOS uses a few bits of this memory, it should
- probably use more.
- </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp47900288"></a>1.5. __code</h3></div></div></div><p>
- All executable code must live in this address space, but
- you can stick read-only data here too. It is addressed
- using the 16-bit address register and special 'code'
- access opcodes. Anything read-only should live in this space.
- </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp47901728"></a>1.6. __bit</h3></div></div></div><p>
- The 8051 has 128 bits of bit-addressible memory that
- lives in the __data segment from 0x20 through
- 0x2f. Special instructions access these bits
- in a single atomic operation. This isn't so much a
- separate address space as a special addressing mode for
- a few bytes in the __data segment.
- </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp47903232"></a>1.7. __sfr, __sfr16, __sfr32, __sbit</h3></div></div></div><p>
- Access to physical registers in the device use this mode
- which declares the variable name, it's type and the
- address it lives at. No memory is allocated for these
- variables.
- </p></div></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp47904768"></a>2. Function calls on the 8051</h2></div></div></div><p>
- Because stack addressing is expensive, and stack space
- limited, the default function call declaration in SDCC
- allocates all parameters and local variables in static global
- memory. Just like fortran. This makes these functions
- non-reentrant, and also consume space for parameters and
- locals even when they are not running. The benefit is smaller
- code and faster execution.
- </p><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp47906240"></a>2.1. __reentrant functions</h3></div></div></div><p>
- All functions which are re-entrant, either due to recursion
- or due to a potential context switch while executing, should
- be marked as __reentrant so that their parameters and local
- variables get allocated on the stack. This ensures that
- these values are not overwritten by another invocation of
- the function.
- </p><p>
- Functions which use significant amounts of space for
- arguments and/or local variables and which are not often
- invoked can also be marked as __reentrant. The resulting
- code will be larger, but the savings in memory are
- frequently worthwhile.
- </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp47908432"></a>2.2. Non __reentrant functions</h3></div></div></div><p>
- All parameters and locals in non-reentrant functions can
- have data space decoration so that they are allocated in
- __xdata, __pdata or __data space as desired. This can avoid
- consuming __data space for infrequently used variables in
- frequently used functions.
- </p><p>
- All library functions called by SDCC, including functions
- for multiplying and dividing large data types, are
- non-reentrant. Because of this, interrupt handlers must not
- invoke any library functions, including the multiply and
- divide code.
- </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp47910576"></a>2.3. __interrupt functions</h3></div></div></div><p>
- Interrupt functions are declared with with an __interrupt
- decoration that includes the interrupt number. SDCC saves
- and restores all of the registers in these functions and
- uses the 'reti' instruction at the end so that they operate
- as stand-alone interrupt handlers. Interrupt functions may
- call the ao_wakeup function to wake AltOS tasks.
- </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp47912144"></a>2.4. __critical functions and statements</h3></div></div></div><p>
- SDCC has built-in support for suspending interrupts during
- critical code. Functions marked as __critical will have
- interrupts suspended for the whole period of
- execution. Individual statements may also be marked as
- __critical which blocks interrupts during the execution of
- that statement. Keeping critical sections as short as
- possible is key to ensuring that interrupts are handled as
- quickly as possible. AltOS doesn't use this form in shared
- code as other compilers wouldn't know what to do. Use
- ao_arch_block_interrupts and ao_arch_release_interrupts instead.
- </p></div></div></div><div class="chapter"><div class="titlepage"><div><div><h1 class="title"><a name="idp47914208"></a>Chapter 4. Task functions</h1></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl class="toc"><dt><span class="section"><a href="#idp47915264">1. ao_add_task</a></span></dt><dt><span class="section"><a href="#idp47917520">2. ao_exit</a></span></dt><dt><span class="section"><a href="#idp53850448">3. ao_sleep</a></span></dt><dt><span class="section"><a href="#idp53854048">4. ao_wakeup</a></span></dt><dt><span class="section"><a href="#idp53857040">5. ao_alarm</a></span></dt><dt><span class="section"><a href="#idp53860224">6. ao_start_scheduler</a></span></dt><dt><span class="section"><a href="#idp53862192">7. ao_clock_init</a></span></dt></dl></div><p>
- This chapter documents how to create, destroy and schedule AltOS tasks.
- </p><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp47915264"></a>1. ao_add_task</h2></div></div></div><pre class="programlisting">
- void
- ao_add_task(__xdata struct ao_task * task,
- void (*start)(void),
- __code char *name);
- </pre><p>
- This initializes the statically allocated task structure,
- assigns a name to it (not used for anything but the task
- display), and the start address. It does not switch to the
- new task. 'start' must not ever return; there is no place
- to return to.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp47917520"></a>2. ao_exit</h2></div></div></div><pre class="programlisting">
- void
- ao_exit(void)
- </pre><p>
- This terminates the current task.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53850448"></a>3. ao_sleep</h2></div></div></div><pre class="programlisting">
- void
- ao_sleep(__xdata void *wchan)
- </pre><p>
- This suspends the current task until 'wchan' is signaled
- by ao_wakeup, or until the timeout, set by ao_alarm,
- fires. If 'wchan' is signaled, ao_sleep returns 0, otherwise
- it returns 1. This is the only way to switch to another task.
- </p><p>
- Because ao_wakeup wakes every task waiting on a particular
- location, ao_sleep should be used in a loop that first checks
- the desired condition, blocks in ao_sleep and then rechecks
- until the condition is satisfied. If the location may be
- signaled from an interrupt handler, the code will need to
- block interrupts around the block of code. Here's a complete
- example:
- </p><pre class="programlisting">
- ao_arch_block_interrupts();
- while (!ao_radio_done)
- ao_sleep(&ao_radio_done);
- ao_arch_release_interrupts();
- </pre><p>
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53854048"></a>4. ao_wakeup</h2></div></div></div><pre class="programlisting">
- void
- ao_wakeup(__xdata void *wchan)
- </pre><p>
- Wake all tasks blocked on 'wchan'. This makes them
- available to be run again, but does not actually switch
- to another task. Here's an example of using this:
- </p><pre class="programlisting">
- if (RFIF & RFIF_IM_DONE) {
- ao_radio_done = 1;
- ao_wakeup(&ao_radio_done);
- RFIF &= ~RFIF_IM_DONE;
- }
- </pre><p>
- Note that this need not block interrupts as the ao_sleep block
- can only be run from normal mode, and so this sequence can
- never be interrupted with execution of the other sequence.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53857040"></a>5. ao_alarm</h2></div></div></div><pre class="programlisting">
- void
- ao_alarm(uint16_t delay);
+static inline void
+ao_arch_save_stack(void);
- void
- ao_clear_alarm(void);
- </pre><p>
- Schedules an alarm to fire in at least 'delay' ticks. If the
- task is asleep when the alarm fires, it will wakeup and
- ao_sleep will return 1. ao_clear_alarm resets any pending
- alarm so that it doesn't fire at some arbitrary point in the
- future.
- </p><pre class="programlisting">
- ao_alarm(ao_packet_master_delay);
- ao_arch_block_interrupts();
- while (!ao_radio_dma_done)
- if (ao_sleep(&ao_radio_dma_done) != 0)
- ao_radio_abort();
- ao_arch_release_interrupts();
- ao_clear_alarm();
- </pre><p>
- In this example, a timeout is set before waiting for
- incoming radio data. If no data is received before the
- timeout fires, ao_sleep will return 1 and then this code
- will abort the radio receive operation.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53860224"></a>6. ao_start_scheduler</h2></div></div></div><pre class="programlisting">
- void
- ao_start_scheduler(void);
- </pre><p>
- This is called from 'main' when the system is all
- initialized and ready to run. It will not return.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53862192"></a>7. ao_clock_init</h2></div></div></div><pre class="programlisting">
- void
- ao_clock_init(void);
- </pre><p>
- This initializes the main CPU clock and switches to it.
- </p></div></div><div class="chapter"><div class="titlepage"><div><div><h1 class="title"><a name="idp53864160"></a>Chapter 5. Timer Functions</h1></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl class="toc"><dt><span class="section"><a href="#idp53865664">1. ao_time</a></span></dt><dt><span class="section"><a href="#idp53867648">2. ao_delay</a></span></dt><dt><span class="section"><a href="#idp53869488">3. ao_timer_set_adc_interval</a></span></dt><dt><span class="section"><a href="#idp53871536">4. ao_timer_init</a></span></dt></dl></div><p>
- AltOS sets up one of the CPU timers to run at 100Hz and
- exposes this tick as the fundemental unit of time. At each
- interrupt, AltOS increments the counter, and schedules any tasks
- waiting for that time to pass, then fires off the sensors to
- collect current data readings. Doing this from the ISR ensures
- that the values are sampled at a regular rate, independent
- of any scheduling jitter.
- </p><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53865664"></a>1. ao_time</h2></div></div></div><pre class="programlisting">
- uint16_t
- ao_time(void)
- </pre><p>
- Returns the current system tick count. Note that this is
- only a 16 bit value, and so it wraps every 655.36 seconds.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53867648"></a>2. ao_delay</h2></div></div></div><pre class="programlisting">
- void
- ao_delay(uint16_t ticks);
- </pre><p>
- Suspend the current task for at least 'ticks' clock units.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53869488"></a>3. ao_timer_set_adc_interval</h2></div></div></div><pre class="programlisting">
- void
- ao_timer_set_adc_interval(uint8_t interval);
- </pre><p>
- This sets the number of ticks between ADC samples. If set
- to 0, no ADC samples are generated. AltOS uses this to
- slow down the ADC sampling rate to save power.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53871536"></a>4. ao_timer_init</h2></div></div></div><pre class="programlisting">
- void
- ao_timer_init(void)
- </pre><p>
- This turns on the 100Hz tick. It is required for any of the
- time-based functions to work. It should be called by 'main'
- before ao_start_scheduler.
- </p></div></div><div class="chapter"><div class="titlepage"><div><div><h1 class="title"><a name="idp53873728"></a>Chapter 6. AltOS Mutexes</h1></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl class="toc"><dt><span class="section"><a href="#idp53875600">1. ao_mutex_get</a></span></dt><dt><span class="section"><a href="#idp53877440">2. ao_mutex_put</a></span></dt></dl></div><p>
- AltOS provides mutexes as a basic synchronization primitive. Each
- mutexes is simply a byte of memory which holds 0 when the mutex
- is free or the task id of the owning task when the mutex is
- owned. Mutex calls are checked—attempting to acquire a mutex
- already held by the current task or releasing a mutex not held
- by the current task will both cause a panic.
- </p><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53875600"></a>1. ao_mutex_get</h2></div></div></div><pre class="programlisting">
- void
- ao_mutex_get(__xdata uint8_t *mutex);
- </pre><p>
- Acquires the specified mutex, blocking if the mutex is
- owned by another task.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53877440"></a>2. ao_mutex_put</h2></div></div></div><pre class="programlisting">
- void
- ao_mutex_put(__xdata uint8_t *mutex);
- </pre><p>
- Releases the specified mutex, waking up all tasks waiting
- for it.
- </p></div></div><div class="chapter"><div class="titlepage"><div><div><h1 class="title"><a name="idp53879408"></a>Chapter 7. DMA engine</h1></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl class="toc"><dt><span class="section"><a href="#idp53882848">1. CC1111 DMA Engine</a></span></dt><dd><dl><dt><span class="section"><a href="#idp53883520">1.1. ao_dma_alloc</a></span></dt><dt><span class="section"><a href="#idp53885696">1.2. ao_dma_set_transfer</a></span></dt><dt><span class="section"><a href="#idp53887968">1.3. ao_dma_start</a></span></dt><dt><span class="section"><a href="#idp53889984">1.4. ao_dma_trigger</a></span></dt><dt><span class="section"><a href="#idp53891824">1.5. ao_dma_abort</a></span></dt></dl></dd><dt><span class="section"><a href="#idp53893968">2. STM32L DMA Engine</a></span></dt><dd><dl><dt><span class="section"><a href="#idp53894640">2.1. ao_dma_alloc</a></span></dt><dt><span class="section"><a href="#idp53896480">2.2. ao_dma_set_transfer</a></span></dt><dt><span class="section"><a href="#idp53898736">2.3. ao_dma_set_isr</a></span></dt><dt><span class="section"><a href="#idp53900816">2.4. ao_dma_start</a></span></dt><dt><span class="section"><a href="#idp53903120">2.5. ao_dma_done_transfer</a></span></dt><dt><span class="section"><a href="#idp53905104">2.6. ao_dma_abort</a></span></dt></dl></dd></dl></div><p>
- The CC1111 and STM32L both contain a useful bit of extra
- hardware in the form of a number of programmable DMA
- engines. They can be configured to copy data in memory, or
- between memory and devices (or even between two devices). AltOS
- exposes a general interface to this hardware and uses it to
- handle both internal and external devices.
- </p><p>
- Because the CC1111 and STM32L DMA engines are different, the
- interface to them is also different. As the DMA engines are
- currently used to implement platform-specific drivers, this
- isn't yet a problem.
- </p><p>
- Code using a DMA engine should allocate one at startup
- time. There is no provision to free them, and if you run out,
- AltOS will simply panic.
- </p><p>
- During operation, the DMA engine is initialized with the
- transfer parameters. Then it is started, at which point it
- awaits a suitable event to start copying data. When copying data
- from hardware to memory, that trigger event is supplied by the
- hardware device. When copying data from memory to hardware, the
- transfer is usually initiated by software.
- </p><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53882848"></a>1. CC1111 DMA Engine</h2></div></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp53883520"></a>1.1. ao_dma_alloc</h3></div></div></div><pre class="programlisting">
- uint8_t
- ao_dma_alloc(__xdata uint8_t *done)
- </pre><p>
- Allocate a DMA engine, returning the identifier. 'done' is
- cleared when the DMA is started, and then receives the
- AO_DMA_DONE bit on a successful transfer or the
- AO_DMA_ABORTED bit if ao_dma_abort was called. Note that it
- is possible to get both bits if the transfer was aborted
- after it had finished.
- </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp53885696"></a>1.2. ao_dma_set_transfer</h3></div></div></div><pre class="programlisting">
- void
- ao_dma_set_transfer(uint8_t id,
- void __xdata *srcaddr,
- void __xdata *dstaddr,
- uint16_t count,
- uint8_t cfg0,
- uint8_t cfg1)
- </pre><p>
- Initializes the specified dma engine to copy data
- from 'srcaddr' to 'dstaddr' for 'count' units. cfg0 and
- cfg1 are values directly out of the CC1111 documentation
- and tell the DMA engine what the transfer unit size,
- direction and step are.
- </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp53887968"></a>1.3. ao_dma_start</h3></div></div></div><pre class="programlisting">
- void
- ao_dma_start(uint8_t id);
- </pre><p>
- Arm the specified DMA engine and await a signal from
- either hardware or software to start transferring data.
- </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp53889984"></a>1.4. ao_dma_trigger</h3></div></div></div><pre class="programlisting">
- void
- ao_dma_trigger(uint8_t id)
- </pre><p>
- Trigger the specified DMA engine to start copying data.
- </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp53891824"></a>1.5. ao_dma_abort</h3></div></div></div><pre class="programlisting">
- void
- ao_dma_abort(uint8_t id)
- </pre><p>
- Terminate any in-progress DMA transation, marking its
- 'done' variable with the AO_DMA_ABORTED bit.
- </p></div></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53893968"></a>2. STM32L DMA Engine</h2></div></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp53894640"></a>2.1. ao_dma_alloc</h3></div></div></div><pre class="programlisting">
- uint8_t ao_dma_done[];
+static inline void
+ao_arch_restore_stack(void);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>These provide all of the support needed to switch
+between tasks.. ao_arch_save_regs must save all CPU
+registers to the current stack, including the
+interrupt enable state. ao_arch_save_stack records the
+current stack location in the current ao_task
+structure. ao_arch_restore_stack switches back to the
+saved stack, restores all registers and branches to
+the saved return address.</p>
+</div>
+</div>
+<div class="sect3">
+<h4 id="_ao_arch_wait_interupt">2.1.3. ao_arch_wait_interupt</h4>
+<div class="literalblock">
+<div class="content">
+<pre>#define ao_arch_wait_interrupt()</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>This stops the CPU, leaving clocks and interrupts
+enabled. When an interrupt is received, this must wake up
+and handle the interrupt. ao_arch_wait_interrupt is entered
+with interrupts disabled to ensure that there is no gap
+between determining that no task wants to run and idling the
+CPU. It must sleep the CPU, process interrupts and then
+disable interrupts again. If the CPU doesn’t have any
+reduced power mode, this must at the least allow pending
+interrupts to be processed.</p>
+</div>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_gpio_operations">2.2. GPIO operations</h3>
+<div class="paragraph">
+<p>These functions provide an abstract interface to configure and
+manipulate GPIO pins.</p>
+</div>
+<div class="sect3">
+<h4 id="_gpio_setup">2.2.1. GPIO setup</h4>
+<div class="paragraph">
+<p>These macros may be invoked at system
+initialization time to configure pins as
+needed for system operation. One tricky aspect
+is that some chips provide direct access to
+specific GPIO pins while others only provide
+access to a whole register full of pins. To
+support this, the GPIO macros provide both
+port+bit and pin arguments. Simply define the
+arguments needed for the target platform and
+leave the others undefined.</p>
+</div>
+<div class="sect4">
+<h5 id="_ao_enable_output">ao_enable_output</h5>
+<div class="literalblock">
+<div class="content">
+<pre>#define ao_enable_output(port, bit, pin, value)</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Set the specified port+bit (also called 'pin')
+for output, initializing to the specified
+value. The macro must avoid driving the pin
+with the opposite value if at all possible.</p>
+</div>
+</div>
+<div class="sect4">
+<h5 id="_ao_enable_input">ao_enable_input</h5>
+<div class="literalblock">
+<div class="content">
+<pre>#define ao_enable_input(port, bit, mode)</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Sets the specified port/bit to be an input
+pin. 'mode' is a combination of one or more of
+the following. Note that some platforms may
+not support the desired mode. In that case,
+the value will not be defined so that the
+program will fail to compile.</p>
+</div>
+<div class="ulist">
+<ul>
+<li>
+<p>AO_EXTI_MODE_PULL_UP. Apply a pull-up to the
+pin; a disconnected pin will read as 1.</p>
+</li>
+<li>
+<p>AO_EXTI_MODE_PULL_DOWN. Apply a pull-down to
+the pin; a disconnected pin will read as 0.</p>
+</li>
+<li>
+<p>0. Don’t apply either a pull-up or
+pull-down. A disconnected pin will read an
+undetermined value.</p>
+</li>
+</ul>
+</div>
+</div>
+</div>
+<div class="sect3">
+<h4 id="_reading_and_writing_gpio_pins">2.2.2. Reading and writing GPIO pins</h4>
+<div class="paragraph">
+<p>These macros read and write individual GPIO pins.</p>
+</div>
+<div class="sect4">
+<h5 id="_ao_gpio_set">ao_gpio_set</h5>
+<div class="literalblock">
+<div class="content">
+<pre>#define ao_gpio_set(port, bit, pin, value)</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Sets the specified port/bit or pin to
+the indicated value</p>
+</div>
+</div>
+<div class="sect4">
+<h5 id="_ao_gpio_get">ao_gpio_get</h5>
+<div class="literalblock">
+<div class="content">
+<pre>#define ao_gpio_get(port, bit, pin)</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Returns either 1 or 0 depending on
+whether the input to the pin is high
+or low.
+== Programming the 8051 with SDCC</p>
+</div>
+<div class="paragraph">
+<p>The 8051 is a primitive 8-bit processor, designed in the mists
+of time in as few transistors as possible. The architecture is
+highly irregular and includes several separate memory
+spaces. Furthermore, accessing stack variables is slow, and
+the stack itself is of limited size. While SDCC papers over
+the instruction set, it is not completely able to hide the
+memory architecture from the application designer.</p>
+</div>
+<div class="paragraph">
+<p>When built on other architectures, the various SDCC-specific
+symbols are #defined as empty strings so they don’t affect the
+compiler.</p>
+</div>
+</div>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_8051_memory_spaces">2.3. 8051 memory spaces</h3>
+<div class="paragraph">
+<p>The <em>data/</em>xdata/__code memory spaces below were completely
+separate in the original 8051 design. In the cc1111, this
+isn’t true—they all live in a single unified 64kB address
+space, and so it’s possible to convert any address into a
+unique 16-bit address. SDCC doesn’t know this, and so a
+'global' address to SDCC consumes 3 bytes of memory, 1 byte as
+a tag indicating the memory space and 2 bytes of offset within
+that space. AltOS avoids these 3-byte addresses as much as
+possible; using them involves a function call per byte
+access. The result is that nearly every variable declaration
+is decorated with a memory space identifier which clutters the
+code but makes the resulting code far smaller and more
+efficient.</p>
+</div>
+<div class="sect3">
+<h4 id="_data">2.3.1. __data</h4>
+<div class="paragraph">
+<p>The 8051 can directly address these 128 bytes of
+memory. This makes them precious so they should be
+reserved for frequently addressed values. Oh, just to
+confuse things further, the 8 general registers in the
+CPU are actually stored in this memory space. There are
+magic instructions to 'bank switch' among 4 banks of
+these registers located at 0x00 - 0x1F. AltOS uses only
+the first bank at 0x00 - 0x07, leaving the other 24
+bytes available for other data.</p>
+</div>
+</div>
+<div class="sect3">
+<h4 id="_idata">2.3.2. __idata</h4>
+<div class="paragraph">
+<p>There are an additional 128 bytes of internal memory
+that share the same address space as __data but which
+cannot be directly addressed. The stack normally
+occupies this space and so AltOS doesn’t place any
+static storage here.</p>
+</div>
+</div>
+<div class="sect3">
+<h4 id="_xdata">2.3.3. __xdata</h4>
+<div class="paragraph">
+<p>This is additional general memory accessed through a
+single 16-bit address register. The CC1111F32 has 32kB
+of memory available here. Most program data should live
+in this memory space.</p>
+</div>
+</div>
+<div class="sect3">
+<h4 id="_pdata">2.3.4. __pdata</h4>
+<div class="paragraph">
+<p>This is an alias for the first 256 bytes of __xdata
+memory, but uses a shorter addressing mode with
+single global 8-bit value for the high 8 bits of the
+address and any of several 8-bit registers for the low 8
+bits. AltOS uses a few bits of this memory, it should
+probably use more.</p>
+</div>
+</div>
+<div class="sect3">
+<h4 id="_code">2.3.5. __code</h4>
+<div class="paragraph">
+<p>All executable code must live in this address space, but
+you can stick read-only data here too. It is addressed
+using the 16-bit address register and special 'code'
+access opcodes. Anything read-only should live in this space.</p>
+</div>
+</div>
+<div class="sect3">
+<h4 id="_bit">2.3.6. __bit</h4>
+<div class="paragraph">
+<p>The 8051 has 128 bits of bit-addressible memory that
+lives in the <em>data segment from 0x20 through
+0x2f. Special instructions access these bits
+in a single atomic operation. This isn’t so much a
+separate address space as a special addressing mode for
+a few bytes in the </em>data segment.</p>
+</div>
+</div>
+<div class="sect3">
+<h4 id="_sfr_sfr16_sfr32_sbit">2.3.7. <em>sfr, </em>sfr16, <em>sfr32, </em>sbit</h4>
+<div class="paragraph">
+<p>Access to physical registers in the device use this mode
+which declares the variable name, its type and the
+address it lives at. No memory is allocated for these
+variables.</p>
+</div>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_function_calls_on_the_8051">2.4. Function calls on the 8051</h3>
+<div class="paragraph">
+<p>Because stack addressing is expensive, and stack space
+limited, the default function call declaration in SDCC
+allocates all parameters and local variables in static global
+memory. Just like fortran. This makes these functions
+non-reentrant, and also consume space for parameters and
+locals even when they are not running. The benefit is smaller
+code and faster execution.</p>
+</div>
+<div class="sect3">
+<h4 id="_reentrant_functions">2.4.1. __reentrant functions</h4>
+<div class="paragraph">
+<p>All functions which are re-entrant, either due to recursion
+or due to a potential context switch while executing, should
+be marked as __reentrant so that their parameters and local
+variables get allocated on the stack. This ensures that
+these values are not overwritten by another invocation of
+the function.</p>
+</div>
+<div class="paragraph">
+<p>Functions which use significant amounts of space for
+arguments and/or local variables and which are not often
+invoked can also be marked as __reentrant. The resulting
+code will be larger, but the savings in memory are
+frequently worthwhile.</p>
+</div>
+</div>
+<div class="sect3">
+<h4 id="_non_reentrant_functions">2.4.2. Non __reentrant functions</h4>
+<div class="paragraph">
+<p>All parameters and locals in non-reentrant functions can
+have data space decoration so that they are allocated in
+<em>xdata, </em>pdata or <em>data space as desired. This can avoid
+consuming </em>data space for infrequently used variables in
+frequently used functions.</p>
+</div>
+<div class="paragraph">
+<p>All library functions called by SDCC, including functions
+for multiplying and dividing large data types, are
+non-reentrant. Because of this, interrupt handlers must not
+invoke any library functions, including the multiply and
+divide code.</p>
+</div>
+</div>
+<div class="sect3">
+<h4 id="_interrupt_functions">2.4.3. __interrupt functions</h4>
+<div class="paragraph">
+<p>Interrupt functions are declared with with an __interrupt
+decoration that includes the interrupt number. SDCC saves
+and restores all of the registers in these functions and
+uses the 'reti' instruction at the end so that they operate
+as stand-alone interrupt handlers. Interrupt functions may
+call the ao_wakeup function to wake AltOS tasks.</p>
+</div>
+</div>
+<div class="sect3">
+<h4 id="_critical_functions_and_statements">2.4.4. __critical functions and statements</h4>
+<div class="paragraph">
+<p>SDCC has built-in support for suspending interrupts during
+critical code. Functions marked as <em>critical will have
+interrupts suspended for the whole period of
+execution. Individual statements may also be marked as
+</em>critical which blocks interrupts during the execution of
+that statement. Keeping critical sections as short as
+possible is key to ensuring that interrupts are handled as
+quickly as possible. AltOS doesn’t use this form in shared
+code as other compilers wouldn’t know what to do. Use
+ao_arch_block_interrupts and ao_arch_release_interrupts instead.</p>
+</div>
+</div>
+</div>
+</div>
+</div>
+<div class="sect1">
+<h2 id="_task_functions">3. Task functions</h2>
+<div class="sectionbody">
+<div class="paragraph">
+<p>This chapter documents how to create, destroy and schedule
+AltOS tasks.</p>
+</div>
+<div class="sect2">
+<h3 id="_ao_add_task">3.1. ao_add_task</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_add_task(__xdata struct ao_task * task,
+ void (*start)(void),
+ __code char *name);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>This initializes the statically allocated task structure,
+assigns a name to it (not used for anything but the task
+display), and the start address. It does not switch to the
+new task. 'start' must not ever return; there is no place
+to return to.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_exit">3.2. ao_exit</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_exit(void)</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>This terminates the current task.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_sleep">3.3. ao_sleep</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_sleep(__xdata void *wchan)</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>This suspends the current task until 'wchan' is signaled
+by ao_wakeup, or until the timeout, set by ao_alarm,
+fires. If 'wchan' is signaled, ao_sleep returns 0, otherwise
+it returns 1. This is the only way to switch to another task.</p>
+</div>
+<div class="paragraph">
+<p>Because ao_wakeup wakes every task waiting on a particular
+location, ao_sleep should be used in a loop that first checks
+the desired condition, blocks in ao_sleep and then rechecks
+until the condition is satisfied. If the location may be
+signaled from an interrupt handler, the code will need to
+block interrupts around the block of code. Here’s a complete
+example:</p>
+</div>
+<div class="literalblock">
+<div class="content">
+<pre>ao_arch_block_interrupts();
+while (!ao_radio_done)
+ ao_sleep(&amp;ao_radio_done);
+ao_arch_release_interrupts();</pre>
+</div>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_wakeup">3.4. ao_wakeup</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_wakeup(__xdata void *wchan)</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Wake all tasks blocked on 'wchan'. This makes them
+available to be run again, but does not actually switch
+to another task. Here’s an example of using this:</p>
+</div>
+<div class="literalblock">
+<div class="content">
+<pre>if (RFIF &amp; RFIF_IM_DONE) {
+ ao_radio_done = 1;
+ ao_wakeup(&amp;ao_radio_done);
+ RFIF &amp;= ~RFIF_IM_DONE;
+}</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Note that this need not block interrupts as the
+ao_sleep block can only be run from normal mode, and
+so this sequence can never be interrupted with
+execution of the other sequence.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_alarm">3.5. ao_alarm</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_alarm(uint16_t delay);
- void
- ao_dma_alloc(uint8_t index);
- </pre><p>
- Reserve a DMA engine for exclusive use by one
- driver.
- </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp53896480"></a>2.2. ao_dma_set_transfer</h3></div></div></div><pre class="programlisting">
- void
- ao_dma_set_transfer(uint8_t id,
- void *peripheral,
- void *memory,
- uint16_t count,
- uint32_t ccr);
- </pre><p>
- Initializes the specified dma engine to copy data between
- 'peripheral' and 'memory' for 'count' units. 'ccr' is a
- value directly out of the STM32L documentation and tells the
- DMA engine what the transfer unit size, direction and step
- are.
- </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp53898736"></a>2.3. ao_dma_set_isr</h3></div></div></div><pre class="programlisting">
- void
- ao_dma_set_isr(uint8_t index, void (*isr)(int))
- </pre><p>
- This sets a function to be called when the DMA transfer
- completes in lieu of setting the ao_dma_done bits. Use this
- when some work needs to be done when the DMA finishes that
- cannot wait until user space resumes.
- </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp53900816"></a>2.4. ao_dma_start</h3></div></div></div><pre class="programlisting">
- void
- ao_dma_start(uint8_t id);
- </pre><p>
- Arm the specified DMA engine and await a signal from either
- hardware or software to start transferring data.
- 'ao_dma_done[index]' is cleared when the DMA is started, and
- then receives the AO_DMA_DONE bit on a successful transfer
- or the AO_DMA_ABORTED bit if ao_dma_abort was called. Note
- that it is possible to get both bits if the transfer was
- aborted after it had finished.
- </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp53903120"></a>2.5. ao_dma_done_transfer</h3></div></div></div><pre class="programlisting">
- void
- ao_dma_done_transfer(uint8_t id);
- </pre><p>
- Signals that a specific DMA engine is done being used. This
- allows multiple drivers to use the same DMA engine safely.
- </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp53905104"></a>2.6. ao_dma_abort</h3></div></div></div><pre class="programlisting">
- void
- ao_dma_abort(uint8_t id)
- </pre><p>
- Terminate any in-progress DMA transation, marking its
- 'done' variable with the AO_DMA_ABORTED bit.
- </p></div></div></div><div class="chapter"><div class="titlepage"><div><div><h1 class="title"><a name="idp53907376"></a>Chapter 8. Stdio interface</h1></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl class="toc"><dt><span class="section"><a href="#idp53908880">1. putchar</a></span></dt><dt><span class="section"><a href="#idp53910768">2. getchar</a></span></dt><dt><span class="section"><a href="#idp53912864">3. flush</a></span></dt><dt><span class="section"><a href="#idp53914896">4. ao_add_stdio</a></span></dt></dl></div><p>
- AltOS offers a stdio interface over USB, serial and the RF
- packet link. This provides for control of the device localy or
- remotely. This is hooked up to the stdio functions by providing
- the standard putchar/getchar/flush functions. These
- automatically multiplex the available communication channels;
- output is always delivered to the channel which provided the
- most recent input.
- </p><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53908880"></a>1. putchar</h2></div></div></div><pre class="programlisting">
- void
- putchar(char c)
- </pre><p>
- Delivers a single character to the current console
- device.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53910768"></a>2. getchar</h2></div></div></div><pre class="programlisting">
- char
- getchar(void)
- </pre><p>
- Reads a single character from any of the available
- console devices. The current console device is set to
- that which delivered this character. This blocks until
- a character is available.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53912864"></a>3. flush</h2></div></div></div><pre class="programlisting">
- void
- flush(void)
- </pre><p>
- Flushes the current console device output buffer. Any
- pending characters will be delivered to the target device.
- xo </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53914896"></a>4. ao_add_stdio</h2></div></div></div><pre class="programlisting">
- void
- ao_add_stdio(char (*pollchar)(void),
- void (*putchar)(char),
- void (*flush)(void))
- </pre><p>
- This adds another console device to the available
- list.
- </p><p>
- 'pollchar' returns either an available character or
- AO_READ_AGAIN if none is available. Significantly, it does
- not block. The device driver must set 'ao_stdin_ready' to
- 1 and call ao_wakeup(&ao_stdin_ready) when it receives
- input to tell getchar that more data is available, at
- which point 'pollchar' will be called again.
- </p><p>
- 'putchar' queues a character for output, flushing if the output buffer is
- full. It may block in this case.
- </p><p>
- 'flush' forces the output buffer to be flushed. It may
- block until the buffer is delivered, but it is not
- required to do so.
- </p></div></div><div class="chapter"><div class="titlepage"><div><div><h1 class="title"><a name="idp53918848"></a>Chapter 9. Command line interface</h1></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl class="toc"><dt><span class="section"><a href="#idp53920256">1. ao_cmd_register</a></span></dt><dt><span class="section"><a href="#idp53928816">2. ao_cmd_lex</a></span></dt><dt><span class="section"><a href="#idp53930896">3. ao_cmd_put16</a></span></dt><dt><span class="section"><a href="#idp53932736">4. ao_cmd_put8</a></span></dt><dt><span class="section"><a href="#idp53934624">5. ao_cmd_white</a></span></dt><dt><span class="section"><a href="#idp53936688">6. ao_cmd_hex</a></span></dt><dt><span class="section"><a href="#idp53938736">7. ao_cmd_decimal</a></span></dt><dt><span class="section"><a href="#idp53940832">8. ao_match_word</a></span></dt><dt><span class="section"><a href="#idp53942912">9. ao_cmd_init</a></span></dt></dl></div><p>
- AltOS includes a simple command line parser which is hooked up
- to the stdio interfaces permitting remote control of the device
- over USB, serial or the RF link as desired. Each command uses a
- single character to invoke it, the remaining characters on the
- line are available as parameters to the command.
- </p><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53920256"></a>1. ao_cmd_register</h2></div></div></div><pre class="programlisting">
- void
- ao_cmd_register(__code struct ao_cmds *cmds)
- </pre><p>
- This registers a set of commands with the command
- parser. There is a fixed limit on the number of command
- sets, the system will panic if too many are registered.
- Each command is defined by a struct ao_cmds entry:
- </p><pre class="programlisting">
- struct ao_cmds {
- char cmd;
- void (*func)(void);
- const char *help;
- };
- </pre><p>
- 'cmd' is the character naming the command. 'func' is the
- function to invoke and 'help' is a string displayed by the
- '?' command. Syntax errors found while executing 'func'
- should be indicated by modifying the global ao_cmd_status
- variable with one of the following values:
- </p><div class="variablelist"><dl class="variablelist"><dt><span class="term">ao_cmd_success</span></dt><dd><p>
- The command was parsed successfully. There is no
- need to assign this value, it is the default.
- </p></dd><dt><span class="term">ao_cmd_lex_error</span></dt><dd><p>
- A token in the line was invalid, such as a number
- containing invalid characters. The low-level
- lexing functions already assign this value as needed.
- </p></dd><dt><span class="term">ao_syntax_error</span></dt><dd><p>
- The command line is invalid for some reason other
- than invalid tokens.
- </p></dd></dl></div><p>
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53928816"></a>2. ao_cmd_lex</h2></div></div></div><pre class="programlisting">
- void
- ao_cmd_lex(void);
- </pre><p>
- This gets the next character out of the command line
- buffer and sticks it into ao_cmd_lex_c. At the end of the
- line, ao_cmd_lex_c will get a newline ('\n') character.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53930896"></a>3. ao_cmd_put16</h2></div></div></div><pre class="programlisting">
- void
- ao_cmd_put16(uint16_t v);
- </pre><p>
- Writes 'v' as four hexadecimal characters.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53932736"></a>4. ao_cmd_put8</h2></div></div></div><pre class="programlisting">
- void
- ao_cmd_put8(uint8_t v);
- </pre><p>
- Writes 'v' as two hexadecimal characters.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53934624"></a>5. ao_cmd_white</h2></div></div></div><pre class="programlisting">
- void
- ao_cmd_white(void)
- </pre><p>
- This skips whitespace by calling ao_cmd_lex while
- ao_cmd_lex_c is either a space or tab. It does not skip
- any characters if ao_cmd_lex_c already non-white.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53936688"></a>6. ao_cmd_hex</h2></div></div></div><pre class="programlisting">
- void
- ao_cmd_hex(void)
- </pre><p>
- This reads a 16-bit hexadecimal value from the command
- line with optional leading whitespace. The resulting value
- is stored in ao_cmd_lex_i;
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53938736"></a>7. ao_cmd_decimal</h2></div></div></div><pre class="programlisting">
- void
- ao_cmd_decimal(void)
- </pre><p>
- This reads a 32-bit decimal value from the command
- line with optional leading whitespace. The resulting value
- is stored in ao_cmd_lex_u32 and the low 16 bits are stored
- in ao_cmd_lex_i;
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53940832"></a>8. ao_match_word</h2></div></div></div><pre class="programlisting">
- uint8_t
- ao_match_word(__code char *word)
- </pre><p>
- This checks to make sure that 'word' occurs on the command
- line. It does not skip leading white space. If 'word' is
- found, then 1 is returned. Otherwise, ao_cmd_status is set to
- ao_cmd_syntax_error and 0 is returned.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53942912"></a>9. ao_cmd_init</h2></div></div></div><pre class="programlisting">
- void
- ao_cmd_init(void
- </pre><p>
- Initializes the command system, setting up the built-in
- commands and adding a task to run the command processing
- loop. It should be called by 'main' before ao_start_scheduler.
- </p></div></div><div class="chapter"><div class="titlepage"><div><div><h1 class="title"><a name="idp53945136"></a>Chapter 10. USB target device</h1></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl class="toc"><dt><span class="section"><a href="#idp53947360">1. ao_usb_flush</a></span></dt><dt><span class="section"><a href="#idp53949504">2. ao_usb_putchar</a></span></dt><dt><span class="section"><a href="#idp53951680">3. ao_usb_pollchar</a></span></dt><dt><span class="section"><a href="#idp53953824">4. ao_usb_getchar</a></span></dt><dt><span class="section"><a href="#idp53955840">5. ao_usb_disable</a></span></dt><dt><span class="section"><a href="#idp53958672">6. ao_usb_enable</a></span></dt><dt><span class="section"><a href="#idp53960784">7. ao_usb_init</a></span></dt></dl></div><p>
- AltOS contains a full-speed USB target device driver. It can be
- programmed to offer any kind of USB target, but to simplify
- interactions with a variety of operating systems, AltOS provides
- only a single target device profile, that of a USB modem which
- has native drivers for Linux, Windows and Mac OS X. It would be
- easy to change the code to provide an alternate target device if
- necessary.
- </p><p>
- To the rest of the system, the USB device looks like a simple
- two-way byte stream. It can be hooked into the command line
- interface if desired, offering control of the device over the
- USB link. Alternatively, the functions can be accessed directly
- to provide for USB-specific I/O.
- </p><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53947360"></a>1. ao_usb_flush</h2></div></div></div><pre class="programlisting">
- void
- ao_usb_flush(void);
- </pre><p>
- Flushes any pending USB output. This queues an 'IN' packet
- to be delivered to the USB host if there is pending data,
- or if the last IN packet was full to indicate to the host
- that there isn't any more pending data available.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53949504"></a>2. ao_usb_putchar</h2></div></div></div><pre class="programlisting">
- void
- ao_usb_putchar(char c);
- </pre><p>
- If there is a pending 'IN' packet awaiting delivery to the
- host, this blocks until that has been fetched. Then, this
- adds a byte to the pending IN packet for delivery to the
- USB host. If the USB packet is full, this queues the 'IN'
- packet for delivery.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53951680"></a>3. ao_usb_pollchar</h2></div></div></div><pre class="programlisting">
- char
- ao_usb_pollchar(void);
- </pre><p>
- If there are no characters remaining in the last 'OUT'
- packet received, this returns AO_READ_AGAIN. Otherwise, it
- returns the next character, reporting to the host that it
- is ready for more data when the last character is gone.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53953824"></a>4. ao_usb_getchar</h2></div></div></div><pre class="programlisting">
- char
- ao_usb_getchar(void);
- </pre><p>
- This uses ao_pollchar to receive the next character,
- blocking while ao_pollchar returns AO_READ_AGAIN.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53955840"></a>5. ao_usb_disable</h2></div></div></div><pre class="programlisting">
- void
- ao_usb_disable(void);
- </pre><p>
- This turns off the USB controller. It will no longer
- respond to host requests, nor return characters. Calling
- any of the i/o routines while the USB device is disabled
- is undefined, and likely to break things. Disabling the
- USB device when not needed saves power.
- </p><p>
- Note that neither TeleDongle nor TeleMetrum are able to
- signal to the USB host that they have disconnected, so
- after disabling the USB device, it's likely that the cable
- will need to be disconnected and reconnected before it
- will work again.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53958672"></a>6. ao_usb_enable</h2></div></div></div><pre class="programlisting">
- void
- ao_usb_enable(void);
- </pre><p>
- This turns the USB controller on again after it has been
- disabled. See the note above about needing to physically
- remove and re-insert the cable to get the host to
- re-initialize the USB link.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53960784"></a>7. ao_usb_init</h2></div></div></div><pre class="programlisting">
- void
- ao_usb_init(void);
- </pre><p>
- This turns the USB controller on, adds a task to handle
- the control end point and adds the usb I/O functions to
- the stdio system. Call this from main before
- ao_start_scheduler.
- </p></div></div><div class="chapter"><div class="titlepage"><div><div><h1 class="title"><a name="idp53963008"></a>Chapter 11. Serial peripherals</h1></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl class="toc"><dt><span class="section"><a href="#idp53965024">1. ao_serial_getchar</a></span></dt><dt><span class="section"><a href="#idp53967056">2. ao_serial_putchar</a></span></dt><dt><span class="section"><a href="#idp53969024">3. ao_serial_drain</a></span></dt><dt><span class="section"><a href="#idp53971024">4. ao_serial_set_speed</a></span></dt><dt><span class="section"><a href="#idp53973056">5. ao_serial_init</a></span></dt></dl></div><p>
- The CC1111 provides two USART peripherals. AltOS uses one for
- asynch serial data, generally to communicate with a GPS device,
- and the other for a SPI bus. The UART is configured to operate
- in 8-bits, no parity, 1 stop bit framing. The default
- configuration has clock settings for 4800, 9600 and 57600 baud
- operation. Additional speeds can be added by computing
- appropriate clock values.
- </p><p>
- To prevent loss of data, AltOS provides receive and transmit
- fifos of 32 characters each.
- </p><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53965024"></a>1. ao_serial_getchar</h2></div></div></div><pre class="programlisting">
- char
- ao_serial_getchar(void);
- </pre><p>
- Returns the next character from the receive fifo, blocking
- until a character is received if the fifo is empty.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53967056"></a>2. ao_serial_putchar</h2></div></div></div><pre class="programlisting">
- void
- ao_serial_putchar(char c);
- </pre><p>
- Adds a character to the transmit fifo, blocking if the
- fifo is full. Starts transmitting characters.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53969024"></a>3. ao_serial_drain</h2></div></div></div><pre class="programlisting">
- void
- ao_serial_drain(void);
- </pre><p>
- Blocks until the transmit fifo is empty. Used internally
- when changing serial speeds.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53971024"></a>4. ao_serial_set_speed</h2></div></div></div><pre class="programlisting">
- void
- ao_serial_set_speed(uint8_t speed);
- </pre><p>
- Changes the serial baud rate to one of
- AO_SERIAL_SPEED_4800, AO_SERIAL_SPEED_9600 or
- AO_SERIAL_SPEED_57600. This first flushes the transmit
- fifo using ao_serial_drain.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53973056"></a>5. ao_serial_init</h2></div></div></div><pre class="programlisting">
- void
- ao_serial_init(void)
- </pre><p>
- Initializes the serial peripheral. Call this from 'main'
- before jumping to ao_start_scheduler. The default speed
- setting is AO_SERIAL_SPEED_4800.
- </p></div></div><div class="chapter"><div class="titlepage"><div><div><h1 class="title"><a name="idp53975248"></a>Chapter 12. CC1111 Radio peripheral</h1></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl class="toc"><dt><span class="section"><a href="#idp53975920">1. Radio Introduction</a></span></dt><dt><span class="section"><a href="#idp53983040">2. ao_radio_set_telemetry</a></span></dt><dt><span class="section"><a href="#idp53985200">3. ao_radio_set_packet</a></span></dt><dt><span class="section"><a href="#idp53987360">4. ao_radio_set_rdf</a></span></dt><dt><span class="section"><a href="#idp53989600">5. ao_radio_idle</a></span></dt><dt><span class="section"><a href="#idp53991648">6. ao_radio_get</a></span></dt><dt><span class="section"><a href="#idp53993680">7. ao_radio_put</a></span></dt><dt><span class="section"><a href="#idp53995616">8. ao_radio_abort</a></span></dt><dt><span class="section"><a href="#idp53997680">9. Radio Telemetry</a></span></dt><dd><dl><dt><span class="section"><a href="#idp53998976">9.1. ao_radio_send</a></span></dt><dt><span class="section"><a href="#idp54001120">9.2. ao_radio_recv</a></span></dt></dl></dd><dt><span class="section"><a href="#idp54003504">10. Radio Direction Finding</a></span></dt><dd><dl><dt><span class="section"><a href="#idp54004656">10.1. ao_radio_rdf</a></span></dt></dl></dd><dt><span class="section"><a href="#idp54006800">11. Radio Packet Mode</a></span></dt><dd><dl><dt><span class="section"><a href="#idp54008112">11.1. ao_packet_putchar</a></span></dt><dt><span class="section"><a href="#idp54010288">11.2. ao_packet_pollchar</a></span></dt><dt><span class="section"><a href="#idp54012368">11.3. ao_packet_slave_start</a></span></dt><dt><span class="section"><a href="#idp54014320">11.4. ao_packet_slave_stop</a></span></dt><dt><span class="section"><a href="#idp54016160">11.5. ao_packet_slave_init</a></span></dt><dt><span class="section"><a href="#idp54018192">11.6. ao_packet_master_init</a></span></dt></dl></dd></dl></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53975920"></a>1. Radio Introduction</h2></div></div></div><p>
- The CC1111 radio transceiver sends and receives digital packets
- with forward error correction and detection. The AltOS driver is
- fairly specific to the needs of the TeleMetrum and TeleDongle
- devices, using it for other tasks may require customization of
- the driver itself. There are three basic modes of operation:
- </p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"><p>
- Telemetry mode. In this mode, TeleMetrum transmits telemetry
- frames at a fixed rate. The frames are of fixed size. This
- is strictly a one-way communication from TeleMetrum to
- TeleDongle.
- </p></li><li class="listitem"><p>
- Packet mode. In this mode, the radio is used to create a
- reliable duplex byte stream between TeleDongle and
- TeleMetrum. This is an asymmetrical protocol with
- TeleMetrum only transmitting in response to a packet sent
- from TeleDongle. Thus getting data from TeleMetrum to
- TeleDongle requires polling. The polling rate is adaptive,
- when no data has been received for a while, the rate slows
- down. The packets are checked at both ends and invalid
- data are ignored.
- </p><p>
- On the TeleMetrum side, the packet link is hooked into the
- stdio mechanism, providing an alternate data path for the
- command processor. It is enabled when the unit boots up in
- 'idle' mode.
- </p><p>
- On the TeleDongle side, the packet link is enabled with a
- command; data from the stdio package is forwarded over the
- packet link providing a connection from the USB command
- stream to the remote TeleMetrum device.
- </p></li><li class="listitem"><p>
- Radio Direction Finding mode. In this mode, TeleMetrum
- constructs a special packet that sounds like an audio tone
- when received by a conventional narrow-band FM
- receiver. This is designed to provide a beacon to track
- the device when other location mechanisms fail.
- </p></li></ol></div><p>
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53983040"></a>2. ao_radio_set_telemetry</h2></div></div></div><pre class="programlisting">
- void
- ao_radio_set_telemetry(void);
- </pre><p>
- Configures the radio to send or receive telemetry
- packets. This includes packet length, modulation scheme and
- other RF parameters. It does not include the base frequency
- or channel though. Those are set at the time of transmission
- or reception, in case the values are changed by the user.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53985200"></a>3. ao_radio_set_packet</h2></div></div></div><pre class="programlisting">
- void
- ao_radio_set_packet(void);
- </pre><p>
- Configures the radio to send or receive packet data. This
- includes packet length, modulation scheme and other RF
- parameters. It does not include the base frequency or
- channel though. Those are set at the time of transmission or
- reception, in case the values are changed by the user.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53987360"></a>4. ao_radio_set_rdf</h2></div></div></div><pre class="programlisting">
- void
- ao_radio_set_rdf(void);
- </pre><p>
- Configures the radio to send RDF 'packets'. An RDF 'packet'
- is a sequence of hex 0x55 bytes sent at a base bit rate of
- 2kbps using a 5kHz deviation. All of the error correction
- and data whitening logic is turned off so that the resulting
- modulation is received as a 1kHz tone by a conventional 70cm
- FM audio receiver.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53989600"></a>5. ao_radio_idle</h2></div></div></div><pre class="programlisting">
- void
- ao_radio_idle(void);
- </pre><p>
- Sets the radio device to idle mode, waiting until it reaches
- that state. This will terminate any in-progress transmit or
- receive operation.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53991648"></a>6. ao_radio_get</h2></div></div></div><pre class="programlisting">
- void
- ao_radio_get(void);
- </pre><p>
- Acquires the radio mutex and then configures the radio
- frequency using the global radio calibration and channel
- values.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53993680"></a>7. ao_radio_put</h2></div></div></div><pre class="programlisting">
- void
- ao_radio_put(void);
- </pre><p>
- Releases the radio mutex.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53995616"></a>8. ao_radio_abort</h2></div></div></div><pre class="programlisting">
- void
- ao_radio_abort(void);
- </pre><p>
- Aborts any transmission or reception process by aborting the
- associated DMA object and calling ao_radio_idle to terminate
- the radio operation.
- </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp53997680"></a>9. Radio Telemetry</h2></div></div></div><p>
- In telemetry mode, you can send or receive a telemetry
- packet. The data from receiving a packet also includes the RSSI
- and status values supplied by the receiver. These are added
- after the telemetry data.
- </p><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp53998976"></a>9.1. ao_radio_send</h3></div></div></div><pre class="programlisting">
- void
- ao_radio_send(__xdata struct ao_telemetry *telemetry);
- </pre><p>
- This sends the specific telemetry packet, waiting for the
- transmission to complete. The radio must have been set to
- telemetry mode. This function calls ao_radio_get() before
- sending, and ao_radio_put() afterwards, to correctly
- serialize access to the radio device.
- </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp54001120"></a>9.2. ao_radio_recv</h3></div></div></div><pre class="programlisting">
- void
- ao_radio_recv(__xdata struct ao_radio_recv *radio);
- </pre><p>
- This blocks waiting for a telemetry packet to be received.
- The radio must have been set to telemetry mode. This
- function calls ao_radio_get() before receiving, and
- ao_radio_put() afterwards, to correctly serialize access
- to the radio device. This returns non-zero if a packet was
- received, or zero if the operation was aborted (from some
- other task calling ao_radio_abort()).
- </p></div></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp54003504"></a>10. Radio Direction Finding</h2></div></div></div><p>
- In radio direction finding mode, there's just one function to
- use
- </p><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp54004656"></a>10.1. ao_radio_rdf</h3></div></div></div><pre class="programlisting">
- void
- ao_radio_rdf(int ms);
- </pre><p>
- This sends an RDF packet lasting for the specified amount
- of time. The maximum length is 1020 ms.
- </p></div></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp54006800"></a>11. Radio Packet Mode</h2></div></div></div><p>
- Packet mode is asymmetrical and is configured at compile time
- for either master or slave mode (but not both). The basic I/O
- functions look the same at both ends, but the internals are
- different, along with the initialization steps.
- </p><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp54008112"></a>11.1. ao_packet_putchar</h3></div></div></div><pre class="programlisting">
- void
- ao_packet_putchar(char c);
- </pre><p>
- If the output queue is full, this first blocks waiting for
- that data to be delivered. Then, queues a character for
- packet transmission. On the master side, this will
- transmit a packet if the output buffer is full. On the
- slave side, any pending data will be sent the next time
- the master polls for data.
- </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp54010288"></a>11.2. ao_packet_pollchar</h3></div></div></div><pre class="programlisting">
- char
- ao_packet_pollchar(void);
- </pre><p>
- This returns a pending input character if available,
- otherwise returns AO_READ_AGAIN. On the master side, if
- this empties the buffer, it triggers a poll for more data.
- </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp54012368"></a>11.3. ao_packet_slave_start</h3></div></div></div><pre class="programlisting">
- void
- ao_packet_slave_start(void);
- </pre><p>
- This is available only on the slave side and starts a task
- to listen for packet data.
- </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp54014320"></a>11.4. ao_packet_slave_stop</h3></div></div></div><pre class="programlisting">
- void
- ao_packet_slave_stop(void);
- </pre><p>
- Disables the packet slave task, stopping the radio receiver.
- </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp54016160"></a>11.5. ao_packet_slave_init</h3></div></div></div><pre class="programlisting">
- void
- ao_packet_slave_init(void);
- </pre><p>
- Adds the packet stdio functions to the stdio package so
- that when packet slave mode is enabled, characters will
- get send and received through the stdio functions.
- </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idp54018192"></a>11.6. ao_packet_master_init</h3></div></div></div><pre class="programlisting">
- void
- ao_packet_master_init(void);
- </pre><p>
- Adds the 'p' packet forward command to start packet mode.
- </p></div></div></div></div></body></html>
+void
+ao_clear_alarm(void);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Schedules an alarm to fire in at least 'delay'
+ticks. If the task is asleep when the alarm fires, it
+will wakeup and ao_sleep will return 1. ao_clear_alarm
+resets any pending alarm so that it doesn’t fire at
+some arbitrary point in the future.</p>
+</div>
+<div class="literalblock">
+<div class="content">
+<pre>ao_alarm(ao_packet_master_delay);
+ao_arch_block_interrupts();
+while (!ao_radio_dma_done)
+if (ao_sleep(&amp;ao_radio_dma_done) != 0)
+ao_radio_abort();
+ao_arch_release_interrupts();
+ao_clear_alarm();</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>In this example, a timeout is set before waiting for
+incoming radio data. If no data is received before the
+timeout fires, ao_sleep will return 1 and then this
+code will abort the radio receive operation.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_start_scheduler">3.6. ao_start_scheduler</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_start_scheduler(void);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>This is called from 'main' when the system is all
+initialized and ready to run. It will not return.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_clock_init">3.7. ao_clock_init</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_clock_init(void);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>This initializes the main CPU clock and switches to it.</p>
+</div>
+</div>
+</div>
+</div>
+<div class="sect1">
+<h2 id="_timer_functions">4. Timer Functions</h2>
+<div class="sectionbody">
+<div class="paragraph">
+<p>AltOS sets up one of the CPU timers to run at 100Hz and
+exposes this tick as the fundemental unit of time. At each
+interrupt, AltOS increments the counter, and schedules any tasks
+waiting for that time to pass, then fires off the sensors to
+collect current data readings. Doing this from the ISR ensures
+that the values are sampled at a regular rate, independent
+of any scheduling jitter.</p>
+</div>
+<div class="sect2">
+<h3 id="_ao_time">4.1. ao_time</h3>
+<div class="literalblock">
+<div class="content">
+<pre>uint16_t
+ao_time(void)</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Returns the current system tick count. Note that this is
+only a 16 bit value, and so it wraps every 655.36 seconds.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_delay">4.2. ao_delay</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_delay(uint16_t ticks);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Suspend the current task for at least 'ticks' clock units.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_timer_set_adc_interval">4.3. ao_timer_set_adc_interval</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_timer_set_adc_interval(uint8_t interval);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>This sets the number of ticks between ADC samples. If set
+to 0, no ADC samples are generated. AltOS uses this to
+slow down the ADC sampling rate to save power.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_timer_init">4.4. ao_timer_init</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_timer_init(void)</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>This turns on the 100Hz tick. It is required for any of the
+time-based functions to work. It should be called by 'main'
+before ao_start_scheduler.</p>
+</div>
+</div>
+</div>
+</div>
+<div class="sect1">
+<h2 id="_altos_mutexes">5. AltOS Mutexes</h2>
+<div class="sectionbody">
+<div class="paragraph">
+<p>AltOS provides mutexes as a basic synchronization primitive. Each
+mutexes is simply a byte of memory which holds 0 when the mutex
+is free or the task id of the owning task when the mutex is
+owned. Mutex calls are checked—attempting to acquire a mutex
+already held by the current task or releasing a mutex not held
+by the current task will both cause a panic.</p>
+</div>
+<div class="sect2">
+<h3 id="_ao_mutex_get">5.1. ao_mutex_get</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_mutex_get(__xdata uint8_t *mutex);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Acquires the specified mutex, blocking if the mutex is
+owned by another task.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_mutex_put">5.2. ao_mutex_put</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_mutex_put(__xdata uint8_t *mutex);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Releases the specified mutex, waking up all tasks waiting
+for it.</p>
+</div>
+</div>
+</div>
+</div>
+<div class="sect1">
+<h2 id="_dma_engine">6. DMA engine</h2>
+<div class="sectionbody">
+<div class="paragraph">
+<p>The CC1111 and STM32L both contain a useful bit of extra
+hardware in the form of a number of programmable DMA
+engines. They can be configured to copy data in memory, or
+between memory and devices (or even between two devices). AltOS
+exposes a general interface to this hardware and uses it to
+handle both internal and external devices.</p>
+</div>
+<div class="paragraph">
+<p>Because the CC1111 and STM32L DMA engines are different, the
+interface to them is also different. As the DMA engines are
+currently used to implement platform-specific drivers, this
+isn’t yet a problem.</p>
+</div>
+<div class="paragraph">
+<p>Code using a DMA engine should allocate one at startup
+time. There is no provision to free them, and if you run out,
+AltOS will simply panic.</p>
+</div>
+<div class="paragraph">
+<p>During operation, the DMA engine is initialized with the
+transfer parameters. Then it is started, at which point it
+awaits a suitable event to start copying data. When copying data
+from hardware to memory, that trigger event is supplied by the
+hardware device. When copying data from memory to hardware, the
+transfer is usually initiated by software.</p>
+</div>
+<div class="sect2">
+<h3 id="_cc1111_dma_engine">6.1. CC1111 DMA Engine</h3>
+<div class="sect3">
+<h4 id="_ao_dma_alloc">6.1.1. ao_dma_alloc</h4>
+<div class="literalblock">
+<div class="content">
+<pre>uint8_t
+ao_dma_alloc(__xdata uint8_t *done)</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Allocate a DMA engine, returning the
+identifier. 'done' is cleared when the DMA is
+started, and then receives the AO_DMA_DONE bit
+on a successful transfer or the AO_DMA_ABORTED
+bit if ao_dma_abort was called. Note that it
+is possible to get both bits if the transfer
+was aborted after it had finished.</p>
+</div>
+</div>
+<div class="sect3">
+<h4 id="_ao_dma_set_transfer">6.1.2. ao_dma_set_transfer</h4>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_dma_set_transfer(uint8_t id,
+void __xdata *srcaddr,
+void __xdata *dstaddr,
+uint16_t count,
+uint8_t cfg0,
+uint8_t cfg1)</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Initializes the specified dma engine to copy
+data from 'srcaddr' to 'dstaddr' for 'count'
+units. cfg0 and cfg1 are values directly out
+of the CC1111 documentation and tell the DMA
+engine what the transfer unit size, direction
+and step are.</p>
+</div>
+</div>
+<div class="sect3">
+<h4 id="_ao_dma_start">6.1.3. ao_dma_start</h4>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_dma_start(uint8_t id);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Arm the specified DMA engine and await a
+signal from either hardware or software to
+start transferring data.</p>
+</div>
+</div>
+<div class="sect3">
+<h4 id="_ao_dma_trigger">6.1.4. ao_dma_trigger</h4>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_dma_trigger(uint8_t id)</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Trigger the specified DMA engine to start
+copying data.</p>
+</div>
+</div>
+<div class="sect3">
+<h4 id="_ao_dma_abort">6.1.5. ao_dma_abort</h4>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_dma_abort(uint8_t id)</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Terminate any in-progress DMA transaction,
+marking its 'done' variable with the
+AO_DMA_ABORTED bit.</p>
+</div>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_stm32l_dma_engine">6.2. STM32L DMA Engine</h3>
+<div class="sect3">
+<h4 id="_ao_dma_alloc_2">6.2.1. ao_dma_alloc</h4>
+<div class="literalblock">
+<div class="content">
+<pre>uint8_t ao_dma_done[];
+
+void
+ao_dma_alloc(uint8_t index);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Reserve a DMA engine for exclusive use by one
+driver.</p>
+</div>
+</div>
+<div class="sect3">
+<h4 id="_ao_dma_set_transfer_2">6.2.2. ao_dma_set_transfer</h4>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_dma_set_transfer(uint8_t id,
+void *peripheral,
+void *memory,
+uint16_t count,
+uint32_t ccr);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Initializes the specified dma engine to copy
+data between 'peripheral' and 'memory' for
+'count' units. 'ccr' is a value directly out
+of the STM32L documentation and tells the DMA
+engine what the transfer unit size, direction
+and step are.</p>
+</div>
+</div>
+<div class="sect3">
+<h4 id="_ao_dma_set_isr">6.2.3. ao_dma_set_isr</h4>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_dma_set_isr(uint8_t index, void (*isr)(int))</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>This sets a function to be called when the DMA
+transfer completes in lieu of setting the
+ao_dma_done bits. Use this when some work
+needs to be done when the DMA finishes that
+cannot wait until user space resumes.</p>
+</div>
+</div>
+<div class="sect3">
+<h4 id="_ao_dma_start_2">6.2.4. ao_dma_start</h4>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_dma_start(uint8_t id);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Arm the specified DMA engine and await a
+signal from either hardware or software to
+start transferring data. 'ao_dma_done[index]'
+is cleared when the DMA is started, and then
+receives the AO_DMA_DONE bit on a successful
+transfer or the AO_DMA_ABORTED bit if
+ao_dma_abort was called. Note that it is
+possible to get both bits if the transfer was
+aborted after it had finished.</p>
+</div>
+</div>
+<div class="sect3">
+<h4 id="_ao_dma_done_transfer">6.2.5. ao_dma_done_transfer</h4>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_dma_done_transfer(uint8_t id);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Signals that a specific DMA engine is done
+being used. This allows multiple drivers to
+use the same DMA engine safely.</p>
+</div>
+</div>
+<div class="sect3">
+<h4 id="_ao_dma_abort_2">6.2.6. ao_dma_abort</h4>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_dma_abort(uint8_t id)</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Terminate any in-progress DMA transaction,
+marking its 'done' variable with the
+AO_DMA_ABORTED bit.</p>
+</div>
+</div>
+</div>
+</div>
+</div>
+<div class="sect1">
+<h2 id="_stdio_interface">7. Stdio interface</h2>
+<div class="sectionbody">
+<div class="paragraph">
+<p>AltOS offers a stdio interface over USB, serial and the RF
+packet link. This provides for control of the device locally or
+remotely. This is hooked up to the stdio functions by providing
+the standard putchar/getchar/flush functions. These
+automatically multiplex the available communication channels;
+output is always delivered to the channel which provided the
+most recent input.</p>
+</div>
+<div class="sect2">
+<h3 id="_putchar">7.1. putchar</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+putchar(char c)</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Delivers a single character to the current console
+device.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_getchar">7.2. getchar</h3>
+<div class="literalblock">
+<div class="content">
+<pre>char
+getchar(void)</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Reads a single character from any of the available
+console devices. The current console device is set to
+that which delivered this character. This blocks until
+a character is available.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_flush">7.3. flush</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+flush(void)</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Flushes the current console device output buffer. Any
+pending characters will be delivered to the target device.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_add_stdio">7.4. ao_add_stdio</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_add_stdio(char (*pollchar)(void),
+void (*putchar)(char),
+void (*flush)(void))</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>This adds another console device to the available
+list.</p>
+</div>
+<div class="paragraph">
+<p>'pollchar' returns either an available character or
+AO_READ_AGAIN if none is available. Significantly, it does
+not block. The device driver must set 'ao_stdin_ready' to
+1 and call ao_wakeup(&ao_stdin_ready) when it receives
+input to tell getchar that more data is available, at
+which point 'pollchar' will be called again.</p>
+</div>
+<div class="paragraph">
+<p>'putchar' queues a character for output, flushing if the output buffer is
+full. It may block in this case.</p>
+</div>
+<div class="paragraph">
+<p>'flush' forces the output buffer to be flushed. It may
+block until the buffer is delivered, but it is not
+required to do so.</p>
+</div>
+</div>
+</div>
+</div>
+<div class="sect1">
+<h2 id="_command_line_interface">8. Command line interface</h2>
+<div class="sectionbody">
+<div class="paragraph">
+<p>AltOS includes a simple command line parser which is hooked up
+to the stdio interfaces permitting remote control of the
+device over USB, serial or the RF link as desired. Each
+command uses a single character to invoke it, the remaining
+characters on the line are available as parameters to the
+command.</p>
+</div>
+<div class="sect2">
+<h3 id="_ao_cmd_register">8.1. ao_cmd_register</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_cmd_register(__code struct ao_cmds *cmds)</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>This registers a set of commands with the command
+parser. There is a fixed limit on the number of command
+sets, the system will panic if too many are registered.
+Each command is defined by a struct ao_cmds entry:</p>
+</div>
+<div class="literalblock">
+<div class="content">
+<pre>struct ao_cmds {
+ char cmd;
+ void (*func)(void);
+ const char *help;
+};</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>'cmd' is the character naming the command. 'func' is the
+function to invoke and 'help' is a string displayed by the
+'?' command. Syntax errors found while executing 'func'
+should be indicated by modifying the global ao_cmd_status
+variable with one of the following values:</p>
+</div>
+<div class="dlist">
+<dl>
+<dt class="hdlist1">ao_cmd_success</dt>
+<dd>
+<p>The command was parsed successfully. There is no need
+to assign this value, it is the default.</p>
+</dd>
+<dt class="hdlist1">ao_cmd_lex_error</dt>
+<dd>
+<p>A token in the line was invalid, such as a number
+containing invalid characters. The low-level lexing
+functions already assign this value as needed.</p>
+</dd>
+<dt class="hdlist1">ao_syntax_error</dt>
+<dd>
+<p>The command line is invalid for some reason other than
+invalid tokens.</p>
+</dd>
+</dl>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_cmd_lex">8.2. ao_cmd_lex</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_cmd_lex(void);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>This gets the next character out of the command line
+buffer and sticks it into ao_cmd_lex_c. At the end of
+the line, ao_cmd_lex_c will get a newline ('\n')
+character.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_cmd_put16">8.3. ao_cmd_put16</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_cmd_put16(uint16_t v);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Writes 'v' as four hexadecimal characters.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_cmd_put8">8.4. ao_cmd_put8</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_cmd_put8(uint8_t v);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Writes 'v' as two hexadecimal characters.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_cmd_white">8.5. ao_cmd_white</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_cmd_white(void)</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>This skips whitespace by calling ao_cmd_lex while
+ao_cmd_lex_c is either a space or tab. It does not
+skip any characters if ao_cmd_lex_c already non-white.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_cmd_hex">8.6. ao_cmd_hex</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_cmd_hex(void)</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>This reads a 16-bit hexadecimal value from the command
+line with optional leading whitespace. The resulting
+value is stored in ao_cmd_lex_i;</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_cmd_decimal">8.7. ao_cmd_decimal</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_cmd_decimal(void)</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>This reads a 32-bit decimal value from the command
+line with optional leading whitespace. The resulting
+value is stored in ao_cmd_lex_u32 and the low 16 bits
+are stored in ao_cmd_lex_i;</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_match_word">8.8. ao_match_word</h3>
+<div class="literalblock">
+<div class="content">
+<pre>uint8_t
+ao_match_word(__code char *word)</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>This checks to make sure that 'word' occurs on the
+command line. It does not skip leading white space. If
+'word' is found, then 1 is returned. Otherwise,
+ao_cmd_status is set to ao_cmd_syntax_error and 0 is
+returned.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_cmd_init">8.9. ao_cmd_init</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_cmd_init(void</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Initializes the command system, setting up the
+built-in commands and adding a task to run the command
+processing loop. It should be called by 'main' before
+ao_start_scheduler.</p>
+</div>
+</div>
+</div>
+</div>
+<div class="sect1">
+<h2 id="_usb_target_device">9. USB target device</h2>
+<div class="sectionbody">
+<div class="paragraph">
+<p>AltOS contains a full-speed USB target device driver. It can
+be programmed to offer any kind of USB target, but to simplify
+interactions with a variety of operating systems, AltOS
+provides only a single target device profile, that of a USB
+modem which has native drivers for Linux, Windows and Mac OS
+X. It would be easy to change the code to provide an alternate
+target device if necessary.</p>
+</div>
+<div class="paragraph">
+<p>To the rest of the system, the USB device looks like a simple
+two-way byte stream. It can be hooked into the command line
+interface if desired, offering control of the device over the
+USB link. Alternatively, the functions can be accessed
+directly to provide for USB-specific I/O.</p>
+</div>
+<div class="sect2">
+<h3 id="_ao_usb_flush">9.1. ao_usb_flush</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_usb_flush(void);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Flushes any pending USB output. This queues an 'IN'
+packet to be delivered to the USB host if there is
+pending data, or if the last IN packet was full to
+indicate to the host that there isn’t any more pending
+data available.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_usb_putchar">9.2. ao_usb_putchar</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_usb_putchar(char c);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>If there is a pending 'IN' packet awaiting delivery to
+the host, this blocks until that has been
+fetched. Then, this adds a byte to the pending IN
+packet for delivery to the USB host. If the USB packet
+is full, this queues the 'IN' packet for delivery.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_usb_pollchar">9.3. ao_usb_pollchar</h3>
+<div class="literalblock">
+<div class="content">
+<pre>char
+ao_usb_pollchar(void);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>If there are no characters remaining in the last 'OUT'
+packet received, this returns
+AO_READ_AGAIN. Otherwise, it returns the next
+character, reporting to the host that it is ready for
+more data when the last character is gone.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_usb_getchar">9.4. ao_usb_getchar</h3>
+<div class="literalblock">
+<div class="content">
+<pre>char
+ao_usb_getchar(void);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>This uses ao_pollchar to receive the next character,
+blocking while ao_pollchar returns AO_READ_AGAIN.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_usb_disable">9.5. ao_usb_disable</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_usb_disable(void);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>This turns off the USB controller. It will no longer
+respond to host requests, nor return
+characters. Calling any of the i/o routines while the
+USB device is disabled is undefined, and likely to
+break things. Disabling the USB device when not needed
+saves power.</p>
+</div>
+<div class="paragraph">
+<p>Note that neither TeleDongle v0.2 nor TeleMetrum v1
+are able to signal to the USB host that they have
+disconnected, so after disabling the USB device, it’s
+likely that the cable will need to be disconnected and
+reconnected before it will work again.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_usb_enable">9.6. ao_usb_enable</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_usb_enable(void);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>This turns the USB controller on again after it has
+been disabled. See the note above about needing to
+physically remove and re-insert the cable to get the
+host to re-initialize the USB link.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_usb_init">9.7. ao_usb_init</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_usb_init(void);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>This turns the USB controller on, adds a task to
+handle the control end point and adds the usb I/O
+functions to the stdio system. Call this from main
+before ao_start_scheduler.</p>
+</div>
+</div>
+</div>
+</div>
+<div class="sect1">
+<h2 id="_serial_peripherals">10. Serial peripherals</h2>
+<div class="sectionbody">
+<div class="paragraph">
+<p>The CC1111 provides two USART peripherals. AltOS uses one for
+asynch serial data, generally to communicate with a GPS
+device, and the other for a SPI bus. The UART is configured to
+operate in 8-bits, no parity, 1 stop bit framing. The default
+configuration has clock settings for 4800, 9600 and 57600 baud
+operation. Additional speeds can be added by computing
+appropriate clock values.</p>
+</div>
+<div class="paragraph">
+<p>To prevent loss of data, AltOS provides receive and transmit
+fifos of 32 characters each.</p>
+</div>
+<div class="sect2">
+<h3 id="_ao_serial_getchar">10.1. ao_serial_getchar</h3>
+<div class="literalblock">
+<div class="content">
+<pre>char
+ao_serial_getchar(void);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Returns the next character from the receive fifo, blocking
+until a character is received if the fifo is empty.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_serial_putchar">10.2. ao_serial_putchar</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_serial_putchar(char c);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Adds a character to the transmit fifo, blocking if the
+fifo is full. Starts transmitting characters.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_serial_drain">10.3. ao_serial_drain</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_serial_drain(void);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Blocks until the transmit fifo is empty. Used internally
+when changing serial speeds.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_serial_set_speed">10.4. ao_serial_set_speed</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_serial_set_speed(uint8_t speed);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Changes the serial baud rate to one of
+AO_SERIAL_SPEED_4800, AO_SERIAL_SPEED_9600 or
+AO_SERIAL_SPEED_57600. This first flushes the transmit
+fifo using ao_serial_drain.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_serial_init">10.5. ao_serial_init</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_serial_init(void)</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Initializes the serial peripheral. Call this from 'main'
+before jumping to ao_start_scheduler. The default speed
+setting is AO_SERIAL_SPEED_4800.</p>
+</div>
+</div>
+</div>
+</div>
+<div class="sect1">
+<h2 id="_cc1111cc1120cc1200_radio_peripheral">11. CC1111/CC1120/CC1200 Radio peripheral</h2>
+<div class="sectionbody">
+<div class="sect2">
+<h3 id="_radio_introduction">11.1. Radio Introduction</h3>
+<div class="paragraph">
+<p>The CC1111, CC1120 and CC1200 radio transceiver sends
+and receives digital packets with forward error
+correction and detection. The AltOS driver is fairly
+specific to the needs of the TeleMetrum and TeleDongle
+devices, using it for other tasks may require
+customization of the driver itself. There are three
+basic modes of operation:</p>
+</div>
+<div class="olist arabic">
+<ol class="arabic">
+<li>
+<p>Telemetry mode. In this mode, TeleMetrum transmits telemetry
+frames at a fixed rate. The frames are of fixed size. This
+is strictly a one-way communication from TeleMetrum to
+TeleDongle.</p>
+</li>
+<li>
+<p>Packet mode. In this mode, the radio is used to create a
+reliable duplex byte stream between TeleDongle and
+TeleMetrum. This is an asymmetrical protocol with
+TeleMetrum only transmitting in response to a packet sent
+from TeleDongle. Thus getting data from TeleMetrum to
+TeleDongle requires polling. The polling rate is adaptive,
+when no data has been received for a while, the rate slows
+down. The packets are checked at both ends and invalid data
+are ignored.</p>
+</li>
+</ol>
+</div>
+<div class="paragraph">
+<p>On the TeleMetrum side, the packet link is hooked into the
+stdio mechanism, providing an alternate data path for the
+command processor. It is enabled when the unit boots up in
+'idle' mode.</p>
+</div>
+<div class="paragraph">
+<p>On the TeleDongle side, the packet link is enabled with a
+command; data from the stdio package is forwarded over the
+packet link providing a connection from the USB command
+stream to the remote TeleMetrum device.</p>
+</div>
+<div class="olist arabic">
+<ol class="arabic">
+<li>
+<p>Radio Direction Finding mode. In this mode, TeleMetrum
+constructs a special packet that sounds like an audio tone
+when received by a conventional narrow-band FM
+receiver. This is designed to provide a beacon to track the
+device when other location mechanisms fail.</p>
+</li>
+</ol>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_radio_set_telemetry">11.2. ao_radio_set_telemetry</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_radio_set_telemetry(void);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Configures the radio to send or receive telemetry
+packets. This includes packet length, modulation scheme and
+other RF parameters. It does not include the base frequency
+or channel though. Those are set at the time of transmission
+or reception, in case the values are changed by the user.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_radio_set_packet">11.3. ao_radio_set_packet</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_radio_set_packet(void);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Configures the radio to send or receive packet data. This
+includes packet length, modulation scheme and other RF
+parameters. It does not include the base frequency or
+channel though. Those are set at the time of transmission or
+reception, in case the values are changed by the user.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_radio_set_rdf">11.4. ao_radio_set_rdf</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_radio_set_rdf(void);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Configures the radio to send RDF 'packets'. An RDF 'packet'
+is a sequence of hex 0x55 bytes sent at a base bit rate of
+2kbps using a 5kHz deviation. All of the error correction
+and data whitening logic is turned off so that the resulting
+modulation is received as a 1kHz tone by a conventional 70cm
+FM audio receiver.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_radio_idle">11.5. ao_radio_idle</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_radio_idle(void);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Sets the radio device to idle mode, waiting until it reaches
+that state. This will terminate any in-progress transmit or
+receive operation.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_radio_get">11.6. ao_radio_get</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_radio_get(void);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Acquires the radio mutex and then configures the radio
+frequency using the global radio calibration and channel
+values.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_radio_put">11.7. ao_radio_put</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_radio_put(void);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Releases the radio mutex.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_ao_radio_abort">11.8. ao_radio_abort</h3>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_radio_abort(void);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Aborts any transmission or reception process by aborting the
+associated DMA object and calling ao_radio_idle to terminate
+the radio operation.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_radio_telemetry">11.9. Radio Telemetry</h3>
+<div class="paragraph">
+<p>In telemetry mode, you can send or receive a telemetry
+packet. The data from receiving a packet also includes the RSSI
+and status values supplied by the receiver. These are added
+after the telemetry data.</p>
+</div>
+<div class="sect3">
+<h4 id="_ao_radio_send">11.9.1. ao_radio_send</h4>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_radio_send(__xdata struct ao_telemetry *telemetry);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>This sends the specific telemetry packet, waiting for the
+transmission to complete. The radio must have been set to
+telemetry mode. This function calls ao_radio_get() before
+sending, and ao_radio_put() afterwards, to correctly
+serialize access to the radio device.</p>
+</div>
+</div>
+<div class="sect3">
+<h4 id="_ao_radio_recv">11.9.2. ao_radio_recv</h4>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_radio_recv(__xdata struct ao_radio_recv *radio);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>This blocks waiting for a telemetry packet to be received.
+The radio must have been set to telemetry mode. This
+function calls ao_radio_get() before receiving, and
+ao_radio_put() afterwards, to correctly serialize access
+to the radio device. This returns non-zero if a packet was
+received, or zero if the operation was aborted (from some
+other task calling ao_radio_abort()).</p>
+</div>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_radio_direction_finding">11.10. Radio Direction Finding</h3>
+<div class="paragraph">
+<p>In radio direction finding mode, there’s just one function to
+use</p>
+</div>
+<div class="sect3">
+<h4 id="_ao_radio_rdf">11.10.1. ao_radio_rdf</h4>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_radio_rdf(int ms);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>This sends an RDF packet lasting for the specified amount
+of time. The maximum length is 1020 ms.</p>
+</div>
+</div>
+</div>
+<div class="sect2">
+<h3 id="_radio_packet_mode">11.11. Radio Packet Mode</h3>
+<div class="paragraph">
+<p>Packet mode is asymmetrical and is configured at compile time
+for either master or slave mode (but not both). The basic I/O
+functions look the same at both ends, but the internals are
+different, along with the initialization steps.</p>
+</div>
+<div class="sect3">
+<h4 id="_ao_packet_putchar">11.11.1. ao_packet_putchar</h4>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_packet_putchar(char c);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>If the output queue is full, this first blocks waiting for
+that data to be delivered. Then, queues a character for
+packet transmission. On the master side, this will
+transmit a packet if the output buffer is full. On the
+slave side, any pending data will be sent the next time
+the master polls for data.</p>
+</div>
+</div>
+<div class="sect3">
+<h4 id="_ao_packet_pollchar">11.11.2. ao_packet_pollchar</h4>
+<div class="literalblock">
+<div class="content">
+<pre>char
+ao_packet_pollchar(void);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>This returns a pending input character if available,
+otherwise returns AO_READ_AGAIN. On the master side, if
+this empties the buffer, it triggers a poll for more data.</p>
+</div>
+</div>
+<div class="sect3">
+<h4 id="_ao_packet_slave_start">11.11.3. ao_packet_slave_start</h4>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_packet_slave_start(void);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>This is available only on the slave side and starts a task
+to listen for packet data.</p>
+</div>
+</div>
+<div class="sect3">
+<h4 id="_ao_packet_slave_stop">11.11.4. ao_packet_slave_stop</h4>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_packet_slave_stop(void);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Disables the packet slave task, stopping the radio receiver.</p>
+</div>
+</div>
+<div class="sect3">
+<h4 id="_ao_packet_slave_init">11.11.5. ao_packet_slave_init</h4>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_packet_slave_init(void);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Adds the packet stdio functions to the stdio package so
+that when packet slave mode is enabled, characters will
+get send and received through the stdio functions.</p>
+</div>
+</div>
+<div class="sect3">
+<h4 id="_ao_packet_master_init">11.11.6. ao_packet_master_init</h4>
+<div class="literalblock">
+<div class="content">
+<pre>void
+ao_packet_master_init(void);</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Adds the 'p' packet forward command to start packet mode.</p>
+</div>
+</div>
+</div>
+</div>
+</div>
+</div>
+<div id="footer">
+<div id="footer-text">
+Last updated 2020-10-22 16:37:05 -0600
+</div>
+</div>
+</body>
+</html>
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projects / web / altusmetrum / blobdiff