# MegaDongle

This is an RF interface designed primarily for use as a ground station
interacting with Altus Metrum altimeters on board high power model 
rockets.  Think of it as a USB to RF interface.  The RF filter components 
are set for use in the vicinity of 435 Mhz.

MegaDongle is intended to supplement and perhaps eventually replace 
[TeleDongle](../TeleDongle) with a product that provides on the order of 
6dB better transmit and receive RF performance, at a modest increase in
manufacturing cost.

For the latest MegaDongle firmware and related software, please
visit the [AltOS](../AltOS) page on this site.

There are no MegaDongle photos to share yet.

## Features ##

### User View ###

* 70cm ham-band transceiver for interaction with Altus Metrum flight compuaters
  like [TeleMetrum](../TeleMetrum/)
* programmed for 38k4 GFSK data rate with forward error correction
* USB interface for power, configuration, and data interface
* 4 pin Tyco MicroMaTch connector for debug and flash programming
* 8 pin Tyco MicroMaTch connector supports serial or SPI interface
* 1.1 x 1.1 inch 4-layer board, fits inexpensive Hammond 1551 plastic enclosure

### Developer View ###

* Hardware Features
	* ST Micros [STM32L151](http://www.st.com/internet/mcu/product/248821.jsp) ARM Cortex M3 based Microcontroller
	* TI [CC1125](http://www.ti.com/product/cc1125) Ultra-High Performance RF Narrowband Transceiver 
	* 150mA 3.3V LDO regulator
		* takes input from USB interface by default
		* output appears on 8-pin companion connector
		* can take input from 8-pin companion connector in non-USB applications
* Software Features
	* Written mostly in C with some ARM assembler
	* Runs from on-chip flash, uses on-chip RAM
	* USB serial emulation for data interface
* Tools Used
	* [gEDA](http://www.gpleda.org/) for schematic capture and PCB layout
* Licenses
	* The hardware is licensed under the [TAPR](http://www.tapr.org) [Open Hardware License](http://www.tapr.org/ohl.html)
	* The software is licensed [GPL version 2](http://www.gnu.org/licenses/old-licenses/gpl-2.0.html)

## [Production History](../production) ##

## Artifacts ##

There is a single manual for most Altus Metrum products including MegaDongle,
which is available in [html](../AltOS/doc/altusmetrum.html) and 
[pdf](../AltOS/doc/altusmetrum.pdf) formats.

The hardware design current gEDA files are available from 
[git.gag.com](http://git.gag.com) in the project 
[hw/megadongle](http://git.gag.com/?p=hw/megadongle;a=summary).  

The firmware can be found on the [AltOS](../AltOS) page on this site.

## Future Plans ##

Our version 0.1 design was abandoned after we discovered the need for more
processing power to implement in software the same FEC approach provided
by the CC1111 we used in [TeleDongle](../TeleDongle).

Version 0.2 prototypes are underway.  

No firm schedule for production and sale of MegaDongle has been set yet.