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Datasheets and Documentation
The first reference for learning to use Freefall is the Freefall Handbook. There you will find a light introduction to the development environment plus details on the device such as pin descriptions, limiting values, and full API documentation for programming new firmware.
For detailed information regarding the ATMEL megaAVR microcontroller in Freefall, such as full specifications, datasheets, instruction set, and application notes, see the ATMEL product card:
For details on the inner-workings of the Freescale MMA7455 accelerometer in Freefall, see the manufacturer's product page:
The following open-source software projects each have their own self-supporting community. If you need help with one of these components, we direct you to the project website. From there you may find documentation and support through forums, irc channels, or mailing lists.
GCC - GNU C Compiler
The GNU Compiler Collection includes compilers for several languages across many hardware platforms. Freefall uses the C compiler in GCC for the AVR target.
AVR-libc - AVR C Library
Just as important as a compiler is a C library. AVR-libc provides the link between the C language and the AVR hardware. Note that only support for essential CPU features is provided. Most peripherals must be controlled using a user library such as Averlicht.
Arduino - Prototyping Platform
The Freefall is based on the same ATmega168 controller as the Arduino platform. In fact, you can program the Freefall using the Arduino IDE. The Arduino community is a particularly good place for those new to electronics. The Arduino forums are very active with over a quarter of a million posts to date.
V-USB - Firmware-only USB driver
The USB driver used in Freefall is the V-USB driver from Objective Development Software GmbH, available under both an open-source and a proprietary license for those who do not wish to publish their firmware sources. The reference projects and forums on the site are useful for learning USB programming.
AVRDUDE - Flashing Utility
To reprogram an AVR a programming utility is required, and AVRDUDE is the best. If you want to go beyond the programming scripts in the example makefiles, read the documentation on the AVRDUDE website or subscribe to their mailing list.
For any other questions regarding Freefall, feel free to contact Stingworks directly:
Freefall Handbook PDF
The complete Freefall Handbook is available as a direct download: