Firmware hacking
Grids' source code is available under the GPL licence.
The code (along with the hardware description files) can be found in the grids directory in our Eurorack modules git repository.
After having cloned the repository, don't forget to run git submodule init && git submodule update to make sure the sub-projects referenced in the code are also pulled.
Toolchain
If you don't mind installing Vagrant and VirtualBox a cozy environment for firmware hacking is available.
If you want to set up your own environment to build Grids' code, avr-gcc and avrdude must be installed. These are standard packages on Linux. On OS X, Crosspack can be installed.
The path to the toolchain can be edited in the AVRLIB_TOOLS_PATH variable in avrlib/makefile.mk directory. It might also be necessary to change the ISP programmer name in the PROGRAMMER variable.
To build the code, use the following command:
make -f grids/makefile
Firmware programming
Programming must be done with an AVR ISP programmer. These are very common and can be found for a few dollars - however, the most reliable units are Atmel's own AVR ISP mkII.
The ISP programmer must be connected on the back of the module - red stripe of the cable on the same side as the ISP text on the board. To upload the code:
make -f grids/makefile bootstrap_all