I got around to the ESP32 earlier than I thought. It is Very easy to set up and alter in the Arduino IDE thanks to all the work done by Barton Dring and his associates. Since I want to use it with Grblgru I didn’t bother with the radio settings much. Tools for that are also described in the wiki.
I chose one of his preconfigured examples for a 4 axis CNC machine. He also has preconfigured examples for the MPCNC and Lowrider with separated stepper motors ie each stepper is assigned its own pin set.
It is slightly easier than the STM32 since an additional FTDI board is not necessary but the correct information libraries must be imported into Arduino IDE for it all to work the first time. After the first setup, which is very well described on the Github site, all is easy. Tailor the config.h and default.h files and get the pin map from cpu-map.h
I wired mine with a breadboard as above with the STM32. I’ll eventually solder it to a more permanent setup.
You need to read and follow all of the links particularly to the roadmap wiki
Another easy 32bit CNC upgrade path for those interested. I didn’t explore 3D printing here at all.
Thanks to Barton Dring for all the work.