Ah; gotcha. It is dirt-simple.
Expanders are programmed using the Arduino IDE with the Teensy extensions. You just need to install those two things. I work on a Mac, but they should work equally as well on Windows.
The modules are programmed in C++ (save the base Android file which is in Androideese). I kept it this way to make them easy to play around with and extend. Steps to compile and update are as follows:
- Open project (TXo or TXi)
- Make desired changes.
- Connect the Expander to Your Computer via USB
- Click the Upload button and the Firmware is Compiled and Updated
You can also drop the HEX file into the Teensy loader and skip the Arduino IDE if you aren't making any changes.
I'm sure there is a command line way to do this - I don't bother. I do use a simple Node.js app that I whipped up to connect to the expander and show logging messages when debugging. I'll be sharing that as well.
I should make a note that there are a couple of new models of Teensy with a lot more horsepower that are pin-compatible. With these, it will be possible to up the sampling rate and also do more with the experimental features of the expanders. I'm pretty excited about this - but haven't had time to properly experiment. They are in my DO NOT TOUCH box until this part of the project is done.