1 <html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>AltOS</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="book" title="AltOS"><div class="titlepage"><div><div><h1 class="title"><a name="id2245959"></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" title="Legal Notice"><a name="id2527643"></a><p>
2 This document is released under the terms of the
3 <a class="ulink" href="http://creativecommons.org/licenses/by-sa/3.0/" target="_top">
4 Creative Commons ShareAlike 3.0
7 </p></div></div><div><div class="revhistory"><table border="1" width="100%" summary="Revision history"><tr><th align="left" valign="top" colspan="2"><b>Revision History</b></th></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><dt><span class="chapter"><a href="#id2513415">1. Overview</a></span></dt><dt><span class="chapter"><a href="#id2537325">2. Programming the 8051 with SDCC</a></span></dt><dd><dl><dt><span class="section"><a href="#id2530770">8051 memory spaces</a></span></dt><dd><dl><dt><span class="section"><a href="#id2545367">__data</a></span></dt><dt><span class="section"><a href="#id2532303">__idata</a></span></dt><dt><span class="section"><a href="#id2543723">__xdata</a></span></dt><dt><span class="section"><a href="#id2527008">__pdata</a></span></dt><dt><span class="section"><a href="#id2523111">__code</a></span></dt><dt><span class="section"><a href="#id2529150">__bit</a></span></dt><dt><span class="section"><a href="#id2516861">__sfr, __sfr16, __sfr32, __sbit</a></span></dt></dl></dd><dt><span class="section"><a href="#id2523406">Function calls on the 8051</a></span></dt><dd><dl><dt><span class="section"><a href="#id2515732">__reentrant functions</a></span></dt><dt><span class="section"><a href="#id2516874">Non __reentrant functions</a></span></dt><dt><span class="section"><a href="#id2545227">__interrupt functions</a></span></dt><dt><span class="section"><a href="#id2529144">__critical functions and statements</a></span></dt></dl></dd></dl></dd><dt><span class="chapter"><a href="#id2536949">3. Task functions</a></span></dt><dd><dl><dt><span class="section"><a href="#id2524681">ao_add_task</a></span></dt><dt><span class="section"><a href="#id2507882">ao_exit</a></span></dt><dt><span class="section"><a href="#id2547084">ao_sleep</a></span></dt><dt><span class="section"><a href="#id2513975">ao_wakeup</a></span></dt><dt><span class="section"><a href="#id2537114">ao_alarm</a></span></dt><dt><span class="section"><a href="#id2523816">ao_wake_task</a></span></dt><dt><span class="section"><a href="#id2520068">ao_start_scheduler</a></span></dt><dt><span class="section"><a href="#id2530057">ao_clock_init</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id2533212">4. Timer Functions</a></span></dt><dd><dl><dt><span class="section"><a href="#id2526439">ao_time</a></span></dt><dt><span class="section"><a href="#id2540144">ao_delay</a></span></dt><dt><span class="section"><a href="#id2539869">ao_timer_set_adc_interval</a></span></dt><dt><span class="section"><a href="#id2544283">ao_timer_init</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id2548207">5. AltOS Mutexes</a></span></dt><dd><dl><dt><span class="section"><a href="#id2528543">ao_mutex_get</a></span></dt><dt><span class="section"><a href="#id2513707">ao_mutex_put</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id2540940">6. CC1111 DMA engine</a></span></dt><dd><dl><dt><span class="section"><a href="#id2537249">ao_dma_alloc</a></span></dt><dt><span class="section"><a href="#id2527171">ao_dma_set_transfer</a></span></dt><dt><span class="section"><a href="#id2535038">ao_dma_start</a></span></dt><dt><span class="section"><a href="#id2544286">ao_dma_trigger</a></span></dt><dt><span class="section"><a href="#id2528708">ao_dma_abort</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id2529890">7. SDCC Stdio interface</a></span></dt><dd><dl><dt><span class="section"><a href="#id2541680">putchar</a></span></dt><dt><span class="section"><a href="#id2528069">getchar</a></span></dt><dt><span class="section"><a href="#id2542910">flush</a></span></dt><dt><span class="section"><a href="#id2536743">ao_add_stdio</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id2535617">8. Command line interface</a></span></dt><dd><dl><dt><span class="section"><a href="#id2531553">ao_cmd_register</a></span></dt><dt><span class="section"><a href="#id2531547">ao_cmd_lex</a></span></dt><dt><span class="section"><a href="#id2527614">ao_cmd_put16</a></span></dt><dt><span class="section"><a href="#id2523654">ao_cmd_put8</a></span></dt><dt><span class="section"><a href="#id2545346">ao_cmd_white</a></span></dt><dt><span class="section"><a href="#id2542088">ao_cmd_hex</a></span></dt><dt><span class="section"><a href="#id2547485">ao_cmd_decimal</a></span></dt><dt><span class="section"><a href="#id2536739">ao_match_word</a></span></dt><dt><span class="section"><a href="#id2547332">ao_cmd_init</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id2532046">9. CC1111 USB target device</a></span></dt><dd><dl><dt><span class="section"><a href="#id2525352">ao_usb_flush</a></span></dt><dt><span class="section"><a href="#id2541180">ao_usb_putchar</a></span></dt><dt><span class="section"><a href="#id2547427">ao_usb_pollchar</a></span></dt><dt><span class="section"><a href="#id2509007">ao_usb_getchar</a></span></dt><dt><span class="section"><a href="#id2527477">ao_usb_disable</a></span></dt><dt><span class="section"><a href="#id2524926">ao_usb_enable</a></span></dt><dt><span class="section"><a href="#id2524815">ao_usb_init</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id2533985">10. CC1111 Serial peripheral</a></span></dt><dd><dl><dt><span class="section"><a href="#id2534584">ao_serial_getchar</a></span></dt><dt><span class="section"><a href="#id2510894">ao_serial_putchar</a></span></dt><dt><span class="section"><a href="#id2512156">ao_serial_drain</a></span></dt><dt><span class="section"><a href="#id2522554">ao_serial_set_speed</a></span></dt><dt><span class="section"><a href="#id2532570">ao_serial_init</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id2538580">11. CC1111 Radio peripheral</a></span></dt><dd><dl><dt><span class="section"><a href="#id2510581">ao_radio_set_telemetry</a></span></dt><dt><span class="section"><a href="#id2539998">ao_radio_set_packet</a></span></dt><dt><span class="section"><a href="#id2543590">ao_radio_set_rdf</a></span></dt><dt><span class="section"><a href="#id2531765">ao_radio_idle</a></span></dt><dt><span class="section"><a href="#id2509740">ao_radio_get</a></span></dt><dt><span class="section"><a href="#id2544567">ao_radio_put</a></span></dt><dt><span class="section"><a href="#id2548225">ao_radio_abort</a></span></dt><dt><span class="section"><a href="#id2523272">ao_radio_send</a></span></dt><dt><span class="section"><a href="#id2527304">ao_radio_recv</a></span></dt><dt><span class="section"><a href="#id2542081">ao_radio_rdf</a></span></dt><dt><span class="section"><a href="#id2548629">ao_packet_putchar</a></span></dt><dt><span class="section"><a href="#id2545931">ao_packet_pollchar</a></span></dt><dt><span class="section"><a href="#id2548616">ao_packet_slave_start</a></span></dt><dt><span class="section"><a href="#id2521552">ao_packet_slave_stop</a></span></dt><dt><span class="section"><a href="#id2520941">ao_packet_slave_init</a></span></dt><dt><span class="section"><a href="#id2532882">ao_packet_master_init</a></span></dt></dl></dd></dl></div><div class="chapter" title="Chapter 1. Overview"><div class="titlepage"><div><div><h2 class="title"><a name="id2513415"></a>Chapter 1. Overview</h2></div></div></div><p>
8 AltOS is a operating system built for the 8051-compatible
9 processor found in the TI cc1111 microcontroller. It's designed
10 to be small and easy to program with. The main features are:
11 </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p>Multi-tasking. While the 8051 doesn't provide separate
12 address spaces, it's often easier to write code that operates
13 in separate threads instead of tying everything into one giant
15 </p></li><li class="listitem"><p>Non-preemptive. This increases latency for thread
16 switching but reduces the number of places where context
17 switching can occur. It also simplifies the operating system
18 design somewhat. Nothing in the target system (rocket flight
19 control) has tight timing requirements, and so this seems like
20 a reasonable compromise.
21 </p></li><li class="listitem"><p>Sleep/wakeup scheduling. Taken directly from ancient
22 Unix designs, these two provide the fundemental scheduling
23 primitive within AltOS.
24 </p></li><li class="listitem"><p>Mutexes. As a locking primitive, mutexes are easier to
25 use than semaphores, at least in my experience.
26 </p></li><li class="listitem"><p>Timers. Tasks can set an alarm which will abort any
27 pending sleep, allowing operations to time-out instead of
29 </p></li></ul></div><p>
31 The device drivers and other subsystems in AltOS are
32 conventionally enabled by invoking their _init() function from
33 the 'main' function before that calls
34 ao_start_scheduler(). These functions initialize the pin
35 assignments, add various commands to the command processor and
36 may add tasks to the scheduler to handle the device. A typical
37 main program, thus, looks like:
38 </p><pre class="programlisting">
44 /* Turn on the LED until the system is stable */
45 ao_led_init(LEDS_AVAILABLE);
46 ao_led_on(AO_LED_RED);
50 ao_monitor_init(AO_LED_GREEN, TRUE);
51 ao_rssi_init(AO_LED_RED);
53 ao_packet_slave_init();
54 ao_packet_master_init();
62 As you can see, a long sequence of subsystems are initialized
63 and then the scheduler is started.
64 </p></div><div class="chapter" title="Chapter 2. Programming the 8051 with SDCC"><div class="titlepage"><div><div><h2 class="title"><a name="id2537325"></a>Chapter 2. Programming the 8051 with SDCC</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id2530770">8051 memory spaces</a></span></dt><dd><dl><dt><span class="section"><a href="#id2545367">__data</a></span></dt><dt><span class="section"><a href="#id2532303">__idata</a></span></dt><dt><span class="section"><a href="#id2543723">__xdata</a></span></dt><dt><span class="section"><a href="#id2527008">__pdata</a></span></dt><dt><span class="section"><a href="#id2523111">__code</a></span></dt><dt><span class="section"><a href="#id2529150">__bit</a></span></dt><dt><span class="section"><a href="#id2516861">__sfr, __sfr16, __sfr32, __sbit</a></span></dt></dl></dd><dt><span class="section"><a href="#id2523406">Function calls on the 8051</a></span></dt><dd><dl><dt><span class="section"><a href="#id2515732">__reentrant functions</a></span></dt><dt><span class="section"><a href="#id2516874">Non __reentrant functions</a></span></dt><dt><span class="section"><a href="#id2545227">__interrupt functions</a></span></dt><dt><span class="section"><a href="#id2529144">__critical functions and statements</a></span></dt></dl></dd></dl></div><p>
65 The 8051 is a primitive 8-bit processor, designed in the mists
66 of time in as few transistors as possible. The architecture is
67 highly irregular and includes several separate memory
68 spaces. Furthermore, accessing stack variables is slow, and the
69 stack itself is of limited size. While SDCC papers over the
70 instruction set, it is not completely able to hide the memory
71 architecture from the application designer.
72 </p><div class="section" title="8051 memory spaces"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2530770"></a>8051 memory spaces</h2></div></div></div><p>
73 The __data/__xdata/__code memory spaces below were completely
74 separate in the original 8051 design. In the cc1111, this
75 isn't true—they all live in a single unified 64kB address
76 space, and so it's possible to convert any address into a
77 unique 16-bit address. SDCC doesn't know this, and so a
78 'global' address to SDCC consumes 3 bytes of memory, 1 byte as
79 a tag indicating the memory space and 2 bytes of offset within
80 that space. AltOS avoids these 3-byte addresses as much as
81 possible; using them involves a function call per byte
82 access. The result is that nearly every variable declaration
83 is decorated with a memory space identifier which clutters the
84 code but makes the resulting code far smaller and more
86 </p><div class="section" title="__data"><div class="titlepage"><div><div><h3 class="title"><a name="id2545367"></a>__data</h3></div></div></div><p>
87 The 8051 can directly address these 128 bytes of
88 memory. This makes them precious so they should be
89 reserved for frequently addressed values. Oh, just to
90 confuse things further, the 8 general registers in the
91 CPU are actually stored in this memory space. There are
92 magic instructions to 'bank switch' among 4 banks of
93 these registers located at 0x00 - 0x1F. AltOS uses only
94 the first bank at 0x00 - 0x07, leaving the other 24
95 bytes available for other data.
96 </p></div><div class="section" title="__idata"><div class="titlepage"><div><div><h3 class="title"><a name="id2532303"></a>__idata</h3></div></div></div><p>
97 There are an additional 128 bytes of internal memory
98 that share the same address space as __data but which
99 cannot be directly addressed. The stack normally
100 occupies this space and so AltOS doesn't place any
102 </p></div><div class="section" title="__xdata"><div class="titlepage"><div><div><h3 class="title"><a name="id2543723"></a>__xdata</h3></div></div></div><p>
103 This is additional general memory accessed through a
104 single 16-bit address register. The CC1111F32 has 32kB
105 of memory available here. Most program data should live
106 in this memory space.
107 </p></div><div class="section" title="__pdata"><div class="titlepage"><div><div><h3 class="title"><a name="id2527008"></a>__pdata</h3></div></div></div><p>
108 This is an alias for the first 256 bytes of __xdata
109 memory, but uses a shorter addressing mode with
110 single global 8-bit value for the high 8 bits of the
111 address and any of several 8-bit registers for the low 8
112 bits. AltOS uses a few bits of this memory, it should
114 </p></div><div class="section" title="__code"><div class="titlepage"><div><div><h3 class="title"><a name="id2523111"></a>__code</h3></div></div></div><p>
115 All executable code must live in this address space, but
116 you can stick read-only data here too. It is addressed
117 using the 16-bit address register and special 'code'
118 access opcodes. Anything read-only should live in this space.
119 </p></div><div class="section" title="__bit"><div class="titlepage"><div><div><h3 class="title"><a name="id2529150"></a>__bit</h3></div></div></div><p>
120 The 8051 has 128 bits of bit-addressible memory that
121 lives in the __data segment from 0x20 through
122 0x2f. Special instructions access these bits
123 in a single atomic operation. This isn't so much a
124 separate address space as a special addressing mode for
125 a few bytes in the __data segment.
126 </p></div><div class="section" title="__sfr, __sfr16, __sfr32, __sbit"><div class="titlepage"><div><div><h3 class="title"><a name="id2516861"></a>__sfr, __sfr16, __sfr32, __sbit</h3></div></div></div><p>
127 Access to physical registers in the device use this mode
128 which declares the variable name, it's type and the
129 address it lives at. No memory is allocated for these
131 </p></div></div><div class="section" title="Function calls on the 8051"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2523406"></a>Function calls on the 8051</h2></div></div></div><p>
132 Because stack addressing is expensive, and stack space
133 limited, the default function call declaration in SDCC
134 allocates all parameters and local variables in static global
135 memory. Just like fortran. This makes these functions
136 non-reentrant, and also consume space for parameters and
137 locals even when they are not running. The benefit is smaller
138 code and faster execution.
139 </p><div class="section" title="__reentrant functions"><div class="titlepage"><div><div><h3 class="title"><a name="id2515732"></a>__reentrant functions</h3></div></div></div><p>
140 All functions which are re-entrant, either due to recursion
141 or due to a potential context switch while executing, should
142 be marked as __reentrant so that their parameters and local
143 variables get allocated on the stack. This ensures that
144 these values are not overwritten by another invocation of
147 Functions which use significant amounts of space for
148 arguments and/or local variables and which are not often
149 invoked can also be marked as __reentrant. The resulting
150 code will be larger, but the savings in memory are
151 frequently worthwhile.
152 </p></div><div class="section" title="Non __reentrant functions"><div class="titlepage"><div><div><h3 class="title"><a name="id2516874"></a>Non __reentrant functions</h3></div></div></div><p>
153 All parameters and locals in non-reentrant functions can
154 have data space decoration so that they are allocated in
155 __xdata, __pdata or __data space as desired. This can avoid
156 consuming __data space for infrequently used variables in
157 frequently used functions.
159 All library functions called by SDCC, including functions
160 for multiplying and dividing large data types, are
161 non-reentrant. Because of this, interrupt handlers must not
162 invoke any library functions, including the multiply and
164 </p></div><div class="section" title="__interrupt functions"><div class="titlepage"><div><div><h3 class="title"><a name="id2545227"></a>__interrupt functions</h3></div></div></div><p>
165 Interrupt functions are declared with with an __interrupt
166 decoration that includes the interrupt number. SDCC saves
167 and restores all of the registers in these functions and
168 uses the 'reti' instruction at the end so that they operate
169 as stand-alone interrupt handlers. Interrupt functions may
170 call the ao_wakeup function to wake AltOS tasks.
171 </p></div><div class="section" title="__critical functions and statements"><div class="titlepage"><div><div><h3 class="title"><a name="id2529144"></a>__critical functions and statements</h3></div></div></div><p>
172 SDCC has built-in support for suspending interrupts during
173 critical code. Functions marked as __critical will have
174 interrupts suspended for the whole period of
175 execution. Individual statements may also be marked as
176 __critical which blocks interrupts during the execution of
177 that statement. Keeping critical sections as short as
178 possible is key to ensuring that interrupts are handled as
180 </p></div></div></div><div class="chapter" title="Chapter 3. Task functions"><div class="titlepage"><div><div><h2 class="title"><a name="id2536949"></a>Chapter 3. Task functions</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id2524681">ao_add_task</a></span></dt><dt><span class="section"><a href="#id2507882">ao_exit</a></span></dt><dt><span class="section"><a href="#id2547084">ao_sleep</a></span></dt><dt><span class="section"><a href="#id2513975">ao_wakeup</a></span></dt><dt><span class="section"><a href="#id2537114">ao_alarm</a></span></dt><dt><span class="section"><a href="#id2523816">ao_wake_task</a></span></dt><dt><span class="section"><a href="#id2520068">ao_start_scheduler</a></span></dt><dt><span class="section"><a href="#id2530057">ao_clock_init</a></span></dt></dl></div><p>
181 This chapter documents how to create, destroy and schedule AltOS tasks.
182 </p><div class="section" title="ao_add_task"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2524681"></a>ao_add_task</h2></div></div></div><pre class="programlisting">
184 ao_add_task(__xdata struct ao_task * task,
188 This initializes the statically allocated task structure,
189 assigns a name to it (not used for anything but the task
190 display), and the start address. It does not switch to the
191 new task. 'start' must not ever return; there is no place
193 </p></div><div class="section" title="ao_exit"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2507882"></a>ao_exit</h2></div></div></div><pre class="programlisting">
197 This terminates the current task.
198 </p></div><div class="section" title="ao_sleep"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2547084"></a>ao_sleep</h2></div></div></div><pre class="programlisting">
200 ao_sleep(__xdata void *wchan)
202 This suspends the current task until 'wchan' is signaled
203 by ao_wakeup, or until the timeout, set by ao_alarm,
204 fires. If 'wchan' is signaled, ao_sleep returns 0, otherwise
205 it returns 1. This is the only way to switch to another task.
207 Because ao_wakeup wakes every task waiting on a particular
208 location, ao_sleep should be used in a loop that first
209 checks the desired condition, blocks in ao_sleep and then
210 rechecks until the condition is satisfied. If the
211 location may be signaled from an interrupt handler, the
212 code will need to block interrupts by using the __critical
213 label around the block of code. Here's a complete example:
214 </p><pre class="programlisting">
215 __critical while (!ao_radio_done)
216 ao_sleep(&ao_radio_done);
218 </p></div><div class="section" title="ao_wakeup"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2513975"></a>ao_wakeup</h2></div></div></div><pre class="programlisting">
220 ao_wakeup(__xdata void *wchan)
222 Wake all tasks blocked on 'wchan'. This makes them
223 available to be run again, but does not actually switch
224 to another task. Here's an example of using this:
225 </p><pre class="programlisting">
226 if (RFIF & RFIF_IM_DONE) {
228 ao_wakeup(&ao_radio_done);
229 RFIF &= ~RFIF_IM_DONE;
232 Note that this need not be enclosed in __critical as the
233 ao_sleep block can only be run from normal mode, and so
234 this sequence can never be interrupted with execution of
236 </p></div><div class="section" title="ao_alarm"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2537114"></a>ao_alarm</h2></div></div></div><pre class="programlisting">
238 ao_alarm(uint16_t delay)
240 Schedules an alarm to fire in at least 'delay' ticks. If
241 the task is asleep when the alarm fires, it will wakeup
242 and ao_sleep will return 1.
243 </p><pre class="programlisting">
244 ao_alarm(ao_packet_master_delay);
245 __critical while (!ao_radio_dma_done)
246 if (ao_sleep(&ao_radio_dma_done) != 0)
249 In this example, a timeout is set before waiting for
250 incoming radio data. If no data is received before the
251 timeout fires, ao_sleep will return 1 and then this code
252 will abort the radio receive operation.
253 </p></div><div class="section" title="ao_wake_task"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2523816"></a>ao_wake_task</h2></div></div></div><pre class="programlisting">
255 ao_wake_task(__xdata struct ao_task *task)
257 Force a specific task to wake up, independent of which
258 'wchan' it is waiting for.
259 </p></div><div class="section" title="ao_start_scheduler"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2520068"></a>ao_start_scheduler</h2></div></div></div><pre class="programlisting">
261 ao_start_scheduler(void)
263 This is called from 'main' when the system is all
264 initialized and ready to run. It will not return.
265 </p></div><div class="section" title="ao_clock_init"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2530057"></a>ao_clock_init</h2></div></div></div><pre class="programlisting">
269 This turns on the external 48MHz clock then switches the
270 hardware to using it. This is required by many of the
271 internal devices like USB. It should be called by the
272 'main' function first, before initializing any of the
273 other devices in the system.
274 </p></div></div><div class="chapter" title="Chapter 4. Timer Functions"><div class="titlepage"><div><div><h2 class="title"><a name="id2533212"></a>Chapter 4. Timer Functions</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id2526439">ao_time</a></span></dt><dt><span class="section"><a href="#id2540144">ao_delay</a></span></dt><dt><span class="section"><a href="#id2539869">ao_timer_set_adc_interval</a></span></dt><dt><span class="section"><a href="#id2544283">ao_timer_init</a></span></dt></dl></div><p>
275 AltOS sets up one of the cc1111 timers to run at 100Hz and
276 exposes this tick as the fundemental unit of time. At each
277 interrupt, AltOS increments the counter, and schedules any tasks
278 waiting for that time to pass, then fires off the ADC system to
279 collect current data readings. Doing this from the ISR ensures
280 that the ADC values are sampled at a regular rate, independent
281 of any scheduling jitter.
282 </p><div class="section" title="ao_time"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2526439"></a>ao_time</h2></div></div></div><pre class="programlisting">
286 Returns the current system tick count. Note that this is
287 only a 16 bit value, and so it wraps every 655.36 seconds.
288 </p></div><div class="section" title="ao_delay"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2540144"></a>ao_delay</h2></div></div></div><pre class="programlisting">
290 ao_delay(uint16_t ticks);
292 Suspend the current task for at least 'ticks' clock units.
293 </p></div><div class="section" title="ao_timer_set_adc_interval"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2539869"></a>ao_timer_set_adc_interval</h2></div></div></div><pre class="programlisting">
295 ao_timer_set_adc_interval(uint8_t interval);
297 This sets the number of ticks between ADC samples. If set
298 to 0, no ADC samples are generated. AltOS uses this to
299 slow down the ADC sampling rate to save power.
300 </p></div><div class="section" title="ao_timer_init"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2544283"></a>ao_timer_init</h2></div></div></div><pre class="programlisting">
304 This turns on the 100Hz tick using the CC1111 timer 1. It
305 is required for any of the time-based functions to
306 work. It should be called by 'main' before ao_start_scheduler.
307 </p></div></div><div class="chapter" title="Chapter 5. AltOS Mutexes"><div class="titlepage"><div><div><h2 class="title"><a name="id2548207"></a>Chapter 5. AltOS Mutexes</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id2528543">ao_mutex_get</a></span></dt><dt><span class="section"><a href="#id2513707">ao_mutex_put</a></span></dt></dl></div><p>
308 AltOS provides mutexes as a basic synchronization primitive. Each
309 mutexes is simply a byte of memory which holds 0 when the mutex
310 is free or the task id of the owning task when the mutex is
311 owned. Mutex calls are checked—attempting to acquire a mutex
312 already held by the current task or releasing a mutex not held
313 by the current task will both cause a panic.
314 </p><div class="section" title="ao_mutex_get"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2528543"></a>ao_mutex_get</h2></div></div></div><pre class="programlisting">
316 ao_mutex_get(__xdata uint8_t *mutex);
318 Acquires the specified mutex, blocking if the mutex is
319 owned by another task.
320 </p></div><div class="section" title="ao_mutex_put"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2513707"></a>ao_mutex_put</h2></div></div></div><pre class="programlisting">
322 ao_mutex_put(__xdata uint8_t *mutex);
324 Releases the specified mutex, waking up all tasks waiting
326 </p></div></div><div class="chapter" title="Chapter 6. CC1111 DMA engine"><div class="titlepage"><div><div><h2 class="title"><a name="id2540940"></a>Chapter 6. CC1111 DMA engine</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id2537249">ao_dma_alloc</a></span></dt><dt><span class="section"><a href="#id2527171">ao_dma_set_transfer</a></span></dt><dt><span class="section"><a href="#id2535038">ao_dma_start</a></span></dt><dt><span class="section"><a href="#id2544286">ao_dma_trigger</a></span></dt><dt><span class="section"><a href="#id2528708">ao_dma_abort</a></span></dt></dl></div><p>
327 The CC1111 contains a useful bit of extra hardware in the form
328 of five programmable DMA engines. They can be configured to copy
329 data in memory, or between memory and devices (or even between
330 two devices). AltOS exposes a general interface to this hardware
331 and uses it to handle radio and SPI data.
333 Code using a DMA engine should allocate one at startup
334 time. There is no provision to free them, and if you run out,
335 AltOS will simply panic.
337 During operation, the DMA engine is initialized with the
338 transfer parameters. Then it is started, at which point it
339 awaits a suitable event to start copying data. When copying data
340 from hardware to memory, that trigger event is supplied by the
341 hardware device. When copying data from memory to hardware, the
342 transfer is usually initiated by software.
343 </p><div class="section" title="ao_dma_alloc"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2537249"></a>ao_dma_alloc</h2></div></div></div><pre class="programlisting">
345 ao_dma_alloc(__xdata uint8_t *done)
347 Allocates a DMA engine, returning the identifier. Whenever
348 this DMA engine completes a transfer. 'done' is cleared
349 when the DMA is started, and then receives the
350 AO_DMA_DONE bit on a successful transfer or the
351 AO_DMA_ABORTED bit if ao_dma_abort was called. Note that
352 it is possible to get both bits if the transfer was
353 aborted after it had finished.
354 </p></div><div class="section" title="ao_dma_set_transfer"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2527171"></a>ao_dma_set_transfer</h2></div></div></div><pre class="programlisting">
356 ao_dma_set_transfer(uint8_t id,
357 void __xdata *srcaddr,
358 void __xdata *dstaddr,
363 Initializes the specified dma engine to copy data
364 from 'srcaddr' to 'dstaddr' for 'count' units. cfg0 and
365 cfg1 are values directly out of the CC1111 documentation
366 and tell the DMA engine what the transfer unit size,
367 direction and step are.
368 </p></div><div class="section" title="ao_dma_start"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2535038"></a>ao_dma_start</h2></div></div></div><pre class="programlisting">
370 ao_dma_start(uint8_t id);
372 Arm the specified DMA engine and await a signal from
373 either hardware or software to start transferring data.
374 </p></div><div class="section" title="ao_dma_trigger"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2544286"></a>ao_dma_trigger</h2></div></div></div><pre class="programlisting">
376 ao_dma_trigger(uint8_t id)
378 Trigger the specified DMA engine to start copying data.
379 </p></div><div class="section" title="ao_dma_abort"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2528708"></a>ao_dma_abort</h2></div></div></div><pre class="programlisting">
381 ao_dma_abort(uint8_t id)
383 Terminate any in-progress DMA transation, marking its
384 'done' variable with the AO_DMA_ABORTED bit.
385 </p></div></div><div class="chapter" title="Chapter 7. SDCC Stdio interface"><div class="titlepage"><div><div><h2 class="title"><a name="id2529890"></a>Chapter 7. SDCC Stdio interface</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id2541680">putchar</a></span></dt><dt><span class="section"><a href="#id2528069">getchar</a></span></dt><dt><span class="section"><a href="#id2542910">flush</a></span></dt><dt><span class="section"><a href="#id2536743">ao_add_stdio</a></span></dt></dl></div><p>
386 AltOS offers a stdio interface over both USB and the RF packet
387 link. This provides for control of the device localy or
388 remotely. This is hooked up to the stdio functions in SDCC by
389 providing the standard putchar/getchar/flush functions. These
390 automatically multiplex the two available communication
391 channels; output is always delivered to the channel which
392 provided the most recent input.
393 </p><div class="section" title="putchar"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2541680"></a>putchar</h2></div></div></div><pre class="programlisting">
397 Delivers a single character to the current console
399 </p></div><div class="section" title="getchar"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2528069"></a>getchar</h2></div></div></div><pre class="programlisting">
403 Reads a single character from any of the available
404 console devices. The current console device is set to
405 that which delivered this character. This blocks until
406 a character is available.
407 </p></div><div class="section" title="flush"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2542910"></a>flush</h2></div></div></div><pre class="programlisting">
411 Flushes the current console device output buffer. Any
412 pending characters will be delivered to the target device.
413 xo </p></div><div class="section" title="ao_add_stdio"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2536743"></a>ao_add_stdio</h2></div></div></div><pre class="programlisting">
415 ao_add_stdio(char (*pollchar)(void),
416 void (*putchar)(char),
419 This adds another console device to the available
422 'pollchar' returns either an available character or
423 AO_READ_AGAIN if none is available. Significantly, it does
424 not block. The device driver must set 'ao_stdin_ready' to
425 1 and call ao_wakeup(&ao_stdin_ready) when it receives
426 input to tell getchar that more data is available, at
427 which point 'pollchar' will be called again.
429 'putchar' queues a character for output, flushing if the output buffer is
430 full. It may block in this case.
432 'flush' forces the output buffer to be flushed. It may
433 block until the buffer is delivered, but it is not
435 </p></div></div><div class="chapter" title="Chapter 8. Command line interface"><div class="titlepage"><div><div><h2 class="title"><a name="id2535617"></a>Chapter 8. Command line interface</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id2531553">ao_cmd_register</a></span></dt><dt><span class="section"><a href="#id2531547">ao_cmd_lex</a></span></dt><dt><span class="section"><a href="#id2527614">ao_cmd_put16</a></span></dt><dt><span class="section"><a href="#id2523654">ao_cmd_put8</a></span></dt><dt><span class="section"><a href="#id2545346">ao_cmd_white</a></span></dt><dt><span class="section"><a href="#id2542088">ao_cmd_hex</a></span></dt><dt><span class="section"><a href="#id2547485">ao_cmd_decimal</a></span></dt><dt><span class="section"><a href="#id2536739">ao_match_word</a></span></dt><dt><span class="section"><a href="#id2547332">ao_cmd_init</a></span></dt></dl></div><p>
436 AltOS includes a simple command line parser which is hooked up
437 to the stdio interfaces permitting remote control of the device
438 over USB or the RF link as desired. Each command uses a single
439 character to invoke it, the remaining characters on the line are
440 available as parameters to the command.
441 </p><div class="section" title="ao_cmd_register"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2531553"></a>ao_cmd_register</h2></div></div></div><pre class="programlisting">
443 ao_cmd_register(__code struct ao_cmds *cmds)
445 This registers a set of commands with the command
446 parser. There is a fixed limit on the number of command
447 sets, the system will panic if too many are registered.
448 Each command is defined by a struct ao_cmds entry:
449 </p><pre class="programlisting">
456 'cmd' is the character naming the command. 'func' is the
457 function to invoke and 'help' is a string displayed by the
458 '?' command. Syntax errors found while executing 'func'
459 should be indicated by modifying the global ao_cmd_status
460 variable with one of the following values:
461 </p><div class="variablelist"><dl><dt></dt><dd><p>
462 The command was parsed successfully. There is no
463 need to assign this value, it is the default.
464 </p></dd><dt></dt><dd><p>
465 A token in the line was invalid, such as a number
466 containing invalid characters. The low-level
467 lexing functions already assign this value as needed.
468 </p></dd><dt></dt><dd><p>
469 The command line is invalid for some reason other
471 </p></dd></dl></div><p>
472 </p></div><div class="section" title="ao_cmd_lex"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2531547"></a>ao_cmd_lex</h2></div></div></div><pre class="programlisting">
476 This gets the next character out of the command line
477 buffer and sticks it into ao_cmd_lex_c. At the end of the
478 line, ao_cmd_lex_c will get a newline ('\n') character.
479 </p></div><div class="section" title="ao_cmd_put16"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2527614"></a>ao_cmd_put16</h2></div></div></div><pre class="programlisting">
481 ao_cmd_put16(uint16_t v);
483 Writes 'v' as four hexadecimal characters.
484 </p></div><div class="section" title="ao_cmd_put8"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2523654"></a>ao_cmd_put8</h2></div></div></div><pre class="programlisting">
486 ao_cmd_put8(uint8_t v);
488 Writes 'v' as two hexadecimal characters.
489 </p></div><div class="section" title="ao_cmd_white"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2545346"></a>ao_cmd_white</h2></div></div></div><pre class="programlisting">
493 This skips whitespace by calling ao_cmd_lex while
494 ao_cmd_lex_c is either a space or tab. It does not skip
495 any characters if ao_cmd_lex_c already non-white.
496 </p></div><div class="section" title="ao_cmd_hex"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2542088"></a>ao_cmd_hex</h2></div></div></div><pre class="programlisting">
500 This reads a 16-bit hexadecimal value from the command
501 line with optional leading whitespace. The resulting value
502 is stored in ao_cmd_lex_i;
503 </p></div><div class="section" title="ao_cmd_decimal"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2547485"></a>ao_cmd_decimal</h2></div></div></div><pre class="programlisting">
507 This reads a 32-bit decimal value from the command
508 line with optional leading whitespace. The resulting value
509 is stored in ao_cmd_lex_u32 and the low 16 bits are stored
511 </p></div><div class="section" title="ao_match_word"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2536739"></a>ao_match_word</h2></div></div></div><pre class="programlisting">
513 ao_match_word(__code char *word)
515 This checks to make sure that 'word' occurs on the command
516 line. It does not skip leading white space. If 'word' is
517 found, then 1 is returned. Otherwise, ao_cmd_status is set to
518 ao_cmd_syntax_error and 0 is returned.
519 </p></div><div class="section" title="ao_cmd_init"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2547332"></a>ao_cmd_init</h2></div></div></div><pre class="programlisting">
523 Initializes the command system, setting up the built-in
524 commands and adding a task to run the command processing
525 loop. It should be called by 'main' before ao_start_scheduler.
526 </p></div></div><div class="chapter" title="Chapter 9. CC1111 USB target device"><div class="titlepage"><div><div><h2 class="title"><a name="id2532046"></a>Chapter 9. CC1111 USB target device</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id2525352">ao_usb_flush</a></span></dt><dt><span class="section"><a href="#id2541180">ao_usb_putchar</a></span></dt><dt><span class="section"><a href="#id2547427">ao_usb_pollchar</a></span></dt><dt><span class="section"><a href="#id2509007">ao_usb_getchar</a></span></dt><dt><span class="section"><a href="#id2527477">ao_usb_disable</a></span></dt><dt><span class="section"><a href="#id2524926">ao_usb_enable</a></span></dt><dt><span class="section"><a href="#id2524815">ao_usb_init</a></span></dt></dl></div><p>
527 The CC1111 contains a full-speed USB target device. It can be
528 programmed to offer any kind of USB target, but to simplify
529 interactions with a variety of operating systems, AltOS provides
530 only a single target device profile, that of a USB modem which
531 has native drivers for Linux, Windows and Mac OS X. It would be
532 easy to change the code to provide an alternate target device if
535 To the rest of the system, the USB device looks like a simple
536 two-way byte stream. It can be hooked into the command line
537 interface if desired, offering control of the device over the
538 USB link. Alternatively, the functions can be accessed directly
539 to provide for USB-specific I/O.
540 </p><div class="section" title="ao_usb_flush"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2525352"></a>ao_usb_flush</h2></div></div></div><pre class="programlisting">
544 Flushes any pending USB output. This queues an 'IN' packet
545 to be delivered to the USB host if there is pending data,
546 or if the last IN packet was full to indicate to the host
547 that there isn't any more pending data available.
548 </p></div><div class="section" title="ao_usb_putchar"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2541180"></a>ao_usb_putchar</h2></div></div></div><pre class="programlisting">
550 ao_usb_putchar(char c);
552 If there is a pending 'IN' packet awaiting delivery to the
553 host, this blocks until that has been fetched. Then, this
554 adds a byte to the pending IN packet for delivery to the
555 USB host. If the USB packet is full, this queues the 'IN'
557 </p></div><div class="section" title="ao_usb_pollchar"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2547427"></a>ao_usb_pollchar</h2></div></div></div><pre class="programlisting">
559 ao_usb_pollchar(void);
561 If there are no characters remaining in the last 'OUT'
562 packet received, this returns AO_READ_AGAIN. Otherwise, it
563 returns the next character, reporting to the host that it
564 is ready for more data when the last character is gone.
565 </p></div><div class="section" title="ao_usb_getchar"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2509007"></a>ao_usb_getchar</h2></div></div></div><pre class="programlisting">
567 ao_usb_getchar(void);
569 This uses ao_pollchar to receive the next character,
570 blocking while ao_pollchar returns AO_READ_AGAIN.
571 </p></div><div class="section" title="ao_usb_disable"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2527477"></a>ao_usb_disable</h2></div></div></div><pre class="programlisting">
573 ao_usb_disable(void);
575 This turns off the USB controller. It will no longer
576 respond to host requests, nor return characters. Calling
577 any of the i/o routines while the USB device is disabled
578 is undefined, and likely to break things. Disabling the
579 USB device when not needed saves power.
581 Note that neither TeleDongle nor TeleMetrum are able to
582 signal to the USB host that they have disconnected, so
583 after disabling the USB device, it's likely that the cable
584 will need to be disconnected and reconnected before it
586 </p></div><div class="section" title="ao_usb_enable"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2524926"></a>ao_usb_enable</h2></div></div></div><pre class="programlisting">
590 This turns the USB controller on again after it has been
591 disabled. See the note above about needing to physically
592 remove and re-insert the cable to get the host to
593 re-initialize the USB link.
594 </p></div><div class="section" title="ao_usb_init"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2524815"></a>ao_usb_init</h2></div></div></div><pre class="programlisting">
598 This turns the USB controller on, adds a task to handle
599 the control end point and adds the usb I/O functions to
600 the stdio system. Call this from main before
602 </p></div></div><div class="chapter" title="Chapter 10. CC1111 Serial peripheral"><div class="titlepage"><div><div><h2 class="title"><a name="id2533985"></a>Chapter 10. CC1111 Serial peripheral</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id2534584">ao_serial_getchar</a></span></dt><dt><span class="section"><a href="#id2510894">ao_serial_putchar</a></span></dt><dt><span class="section"><a href="#id2512156">ao_serial_drain</a></span></dt><dt><span class="section"><a href="#id2522554">ao_serial_set_speed</a></span></dt><dt><span class="section"><a href="#id2532570">ao_serial_init</a></span></dt></dl></div><p>
603 The CC1111 provides two USART peripherals. AltOS uses one for
604 asynch serial data, generally to communicate with a GPS device,
605 and the other for a SPI bus. The UART is configured to operate
606 in 8-bits, no parity, 1 stop bit framing. The default
607 configuration has clock settings for 4800, 9600 and 57600 baud
608 operation. Additional speeds can be added by computing
609 appropriate clock values.
611 To prevent loss of data, AltOS provides receive and transmit
612 fifos of 32 characters each.
613 </p><div class="section" title="ao_serial_getchar"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2534584"></a>ao_serial_getchar</h2></div></div></div><pre class="programlisting">
615 ao_serial_getchar(void);
617 Returns the next character from the receive fifo, blocking
618 until a character is received if the fifo is empty.
619 </p></div><div class="section" title="ao_serial_putchar"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2510894"></a>ao_serial_putchar</h2></div></div></div><pre class="programlisting">
621 ao_serial_putchar(char c);
623 Adds a character to the transmit fifo, blocking if the
624 fifo is full. Starts transmitting characters.
625 </p></div><div class="section" title="ao_serial_drain"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2512156"></a>ao_serial_drain</h2></div></div></div><pre class="programlisting">
627 ao_serial_drain(void);
629 Blocks until the transmit fifo is empty. Used internally
630 when changing serial speeds.
631 </p></div><div class="section" title="ao_serial_set_speed"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2522554"></a>ao_serial_set_speed</h2></div></div></div><pre class="programlisting">
633 ao_serial_set_speed(uint8_t speed);
635 Changes the serial baud rate to one of
636 AO_SERIAL_SPEED_4800, AO_SERIAL_SPEED_9600 or
637 AO_SERIAL_SPEED_57600. This first flushes the transmit
638 fifo using ao_serial_drain.
639 </p></div><div class="section" title="ao_serial_init"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2532570"></a>ao_serial_init</h2></div></div></div><pre class="programlisting">
643 Initializes the serial peripheral. Call this from 'main'
644 before jumping to ao_start_scheduler. The default speed
645 setting is AO_SERIAL_SPEED_4800.
646 </p></div></div><div class="chapter" title="Chapter 11. CC1111 Radio peripheral"><div class="titlepage"><div><div><h2 class="title"><a name="id2538580"></a>Chapter 11. CC1111 Radio peripheral</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id2510581">ao_radio_set_telemetry</a></span></dt><dt><span class="section"><a href="#id2539998">ao_radio_set_packet</a></span></dt><dt><span class="section"><a href="#id2543590">ao_radio_set_rdf</a></span></dt><dt><span class="section"><a href="#id2531765">ao_radio_idle</a></span></dt><dt><span class="section"><a href="#id2509740">ao_radio_get</a></span></dt><dt><span class="section"><a href="#id2544567">ao_radio_put</a></span></dt><dt><span class="section"><a href="#id2548225">ao_radio_abort</a></span></dt><dt><span class="section"><a href="#id2523272">ao_radio_send</a></span></dt><dt><span class="section"><a href="#id2527304">ao_radio_recv</a></span></dt><dt><span class="section"><a href="#id2542081">ao_radio_rdf</a></span></dt><dt><span class="section"><a href="#id2548629">ao_packet_putchar</a></span></dt><dt><span class="section"><a href="#id2545931">ao_packet_pollchar</a></span></dt><dt><span class="section"><a href="#id2548616">ao_packet_slave_start</a></span></dt><dt><span class="section"><a href="#id2521552">ao_packet_slave_stop</a></span></dt><dt><span class="section"><a href="#id2520941">ao_packet_slave_init</a></span></dt><dt><span class="section"><a href="#id2532882">ao_packet_master_init</a></span></dt></dl></div><p>
647 The CC1111 radio transceiver sends and receives digital packets
648 with forward error correction and detection. The AltOS driver is
649 fairly specific to the needs of the TeleMetrum and TeleDongle
650 devices, using it for other tasks may require customization of
651 the driver itself. There are three basic modes of operation:
652 </p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"><p>
653 Telemetry mode. In this mode, TeleMetrum transmits telemetry
654 frames at a fixed rate. The frames are of fixed size. This
655 is strictly a one-way communication from TeleMetrum to
657 </p></li><li class="listitem"><p>
658 Packet mode. In this mode, the radio is used to create a
659 reliable duplex byte stream between TeleDongle and
660 TeleMetrum. This is an asymmetrical protocol with
661 TeleMetrum only transmitting in response to a packet sent
662 from TeleDongle. Thus getting data from TeleMetrum to
663 TeleDongle requires polling. The polling rate is adaptive,
664 when no data has been received for a while, the rate slows
665 down. The packets are checked at both ends and invalid
668 On the TeleMetrum side, the packet link is hooked into the
669 stdio mechanism, providing an alternate data path for the
670 command processor. It is enabled when the unit boots up in
673 On the TeleDongle side, the packet link is enabled with a
674 command; data from the stdio package is forwarded over the
675 packet link providing a connection from the USB command
676 stream to the remote TeleMetrum device.
677 </p></li><li class="listitem"><p>
678 Radio Direction Finding mode. In this mode, TeleMetrum
679 constructs a special packet that sounds like an audio tone
680 when received by a conventional narrow-band FM
681 receiver. This is designed to provide a beacon to track
682 the device when other location mechanisms fail.
683 </p></li></ol></div><p>
684 </p><div class="section" title="ao_radio_set_telemetry"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2510581"></a>ao_radio_set_telemetry</h2></div></div></div><pre class="programlisting">
686 ao_radio_set_telemetry(void);
688 Configures the radio to send or receive telemetry
689 packets. This includes packet length, modulation scheme and
690 other RF parameters. It does not include the base frequency
691 or channel though. Those are set at the time of transmission
692 or reception, in case the values are changed by the user.
693 </p></div><div class="section" title="ao_radio_set_packet"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2539998"></a>ao_radio_set_packet</h2></div></div></div><pre class="programlisting">
695 ao_radio_set_packet(void);
697 Configures the radio to send or receive packet data. This
698 includes packet length, modulation scheme and other RF
699 parameters. It does not include the base frequency or
700 channel though. Those are set at the time of transmission or
701 reception, in case the values are changed by the user.
702 </p></div><div class="section" title="ao_radio_set_rdf"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2543590"></a>ao_radio_set_rdf</h2></div></div></div><pre class="programlisting">
704 ao_radio_set_rdf(void);
706 Configures the radio to send RDF 'packets'. An RDF 'packet'
707 is a sequence of hex 0x55 bytes sent at a base bit rate of
708 2kbps using a 5kHz deviation. All of the error correction
709 and data whitening logic is turned off so that the resulting
710 modulation is received as a 1kHz tone by a conventional 70cm
712 </p></div><div class="section" title="ao_radio_idle"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2531765"></a>ao_radio_idle</h2></div></div></div><pre class="programlisting">
716 Sets the radio device to idle mode, waiting until it reaches
717 that state. This will terminate any in-progress transmit or
719 </p></div><div class="section" title="ao_radio_get"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2509740"></a>ao_radio_get</h2></div></div></div><pre class="programlisting">
723 Acquires the radio mutex and then configures the radio
724 frequency using the global radio calibration and channel
726 </p></div><div class="section" title="ao_radio_put"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2544567"></a>ao_radio_put</h2></div></div></div><pre class="programlisting">
730 Releases the radio mutex.
731 </p></div><div class="section" title="ao_radio_abort"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2548225"></a>ao_radio_abort</h2></div></div></div><pre class="programlisting">
733 ao_radio_abort(void);
735 Aborts any transmission or reception process by aborting the
736 associated DMA object and calling ao_radio_idle to terminate
739 In telemetry mode, you can send or receive a telemetry
740 packet. The data from receiving a packet also includes the RSSI
741 and status values supplied by the receiver. These are added
742 after the telemetry data.
743 </p><div class="section" title="ao_radio_send"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2523272"></a>ao_radio_send</h2></div></div></div><pre class="programlisting">
745 ao_radio_send(__xdata struct ao_telemetry *telemetry);
747 This sends the specific telemetry packet, waiting for the
748 transmission to complete. The radio must have been set to
749 telemetry mode. This function calls ao_radio_get() before
750 sending, and ao_radio_put() afterwards, to correctly
751 serialize access to the radio device.
752 </p></div><div class="section" title="ao_radio_recv"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2527304"></a>ao_radio_recv</h2></div></div></div><pre class="programlisting">
754 ao_radio_recv(__xdata struct ao_radio_recv *radio);
756 This blocks waiting for a telemetry packet to be received.
757 The radio must have been set to telemetry mode. This
758 function calls ao_radio_get() before receiving, and
759 ao_radio_put() afterwards, to correctly serialize access
760 to the radio device. This returns non-zero if a packet was
761 received, or zero if the operation was aborted (from some
762 other task calling ao_radio_abort()).
764 In radio direction finding mode, there's just one function to
766 </p><div class="section" title="ao_radio_rdf"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2542081"></a>ao_radio_rdf</h2></div></div></div><pre class="programlisting">
768 ao_radio_rdf(int ms);
770 This sends an RDF packet lasting for the specified amount
771 of time. The maximum length is 1020 ms.
773 Packet mode is asymmetrical and is configured at compile time
774 for either master or slave mode (but not both). The basic I/O
775 functions look the same at both ends, but the internals are
776 different, along with the initialization steps.
777 </p><div class="section" title="ao_packet_putchar"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2548629"></a>ao_packet_putchar</h2></div></div></div><pre class="programlisting">
779 ao_packet_putchar(char c);
781 If the output queue is full, this first blocks waiting for
782 that data to be delivered. Then, queues a character for
783 packet transmission. On the master side, this will
784 transmit a packet if the output buffer is full. On the
785 slave side, any pending data will be sent the next time
786 the master polls for data.
787 </p></div><div class="section" title="ao_packet_pollchar"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2545931"></a>ao_packet_pollchar</h2></div></div></div><pre class="programlisting">
789 ao_packet_pollchar(void);
791 This returns a pending input character if available,
792 otherwise returns AO_READ_AGAIN. On the master side, if
793 this empties the buffer, it triggers a poll for more data.
794 </p></div><div class="section" title="ao_packet_slave_start"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2548616"></a>ao_packet_slave_start</h2></div></div></div><pre class="programlisting">
796 ao_packet_slave_start(void);
798 This is available only on the slave side and starts a task
799 to listen for packet data.
800 </p></div><div class="section" title="ao_packet_slave_stop"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2521552"></a>ao_packet_slave_stop</h2></div></div></div><pre class="programlisting">
802 ao_packet_slave_stop(void);
804 Disables the packet slave task, stopping the radio receiver.
805 </p></div><div class="section" title="ao_packet_slave_init"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2520941"></a>ao_packet_slave_init</h2></div></div></div><pre class="programlisting">
807 ao_packet_slave_init(void);
809 Adds the packet stdio functions to the stdio package so
810 that when packet slave mode is enabled, characters will
811 get send and received through the stdio functions.
812 </p></div><div class="section" title="ao_packet_master_init"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2532882"></a>ao_packet_master_init</h2></div></div></div><pre class="programlisting">
814 ao_packet_master_init(void);
816 Adds the 'p' packet forward command to start packet mode.
817 </p></div></div></div></body></html>
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