sha204_playground/avr

sha204_playground firmware: straight avr-gcc version

Here are the source for the sha204_playground firmware, to be compiled with avr-gcc against the LUFA library.

Compilation / usage

Get the LUFA library and copy the LUFA folder to the subdirectory avr/LUFA.

The SHA204 library supports both Single Wire interface and I2C interface (on mega's hardware I2C=TWI pins). Just select the interface at the beginning of sha204_playground.cpp file.

Modifications to match your hardware setup are done mostly in makefile and SHA204/SHA204SWI_hardware_config.h or SHA204/SHA204TWI_hardware_config.h.

Compile (make) and upload to your board with ATSHA204 (how to do this depends on your bootloader).

After reset, your board should enumerate as a CDC Serial Device (also as a keyboard, but that functionality isn't used yet). Note that an .inf file might be required on Windows systems.

Connect to this Serial device using a serial terminal (e.g. puTTY, picocom, minicom, screen, ...) and you should be presented with a "menu" of commands that interact with ATSHA204 device.

Communicating with the firmware

Probably the first thing to try is pressing k (to test waking the ATSHA up) and pressing s (to print the serial number of your device).

Alternatively (depending on the functionality required), you can use the talk_to_sha204.py script to talk to the ATSHA via this firmware.

Binary mode

The firmware supports a "binary mode", for use with scripts. For a demonstration on how this is done, have a look at the python script talk_to_sha204.py.

Notes

• The subdirectory SHA204 contains a re-usable library, working on both AVR8 and XMEGA architectures. Note that only 16MHz and 32MHz CPU speeds are tested.
• At the moment, the Single-Wire Interface for ATSHA204 is implemented by bit-banging in C (so a speedy CPU is probably required). I2C interface uses hardware TWI module in (x)megas.
• The firmware also enumerates as a Keyboard. This functionality is not used at the moment; see LufaLayer.h for the functions that can generate "keypresses".

VID/PID

Every USB device has a Vendor/Product identifying signature. This is set in software here (Descriptors.c). The current code uses a pair which belongs to the LUFA library. DO NOT USE IT for any other than development purposes only! See LUFA's VID/PID page.

Credits

• The whole USB interface utilizes Dean Camera's excellent LUFA library, and builds on several LUFA demos supplied with the library.
• I've started with bettse's version of a SHA204 library for Arduino on github, and modified it to work on XMEGA firmware, and not necessarily as an Arduino library.

License

My code is (c) flabbergast. MIT license (see LICENSE file). Portions of the code come from LUFA demos, this is licensed by LUFA's license. The original code from SHA204 library is licensed by Apache V2.0 license.