In my previous post I added a Raspberry Pi Zero inside the calculator. Why not use also it to program/debug the calculator firmware ? What I have done is basically to follow this adafruit tutorial. I soldered only SWDIO to Raspberry Pi #24 and SWCLK to Raspberry Pi #25. This seems to be enough, and the reset button of the calculator is not far away if needed. Using the following OpenOCD script, it is now possible to debug or program the calculator over the air ! Read more ...

I was having a Raspberry Pi Zero sitting on my desk for a long time, searching for something to do with it. I also wanted to to learn STM32, mainly DMA and interrupts. As the calculator is powered by an STM32F412, why not put them together ? TL;DR, the result: The idea was to add an application on the calculator, which will display the output of the Raspberry Pi, and send keystroke from the keyboard to it. Read more ...