I just got a Nucleo F411RE board and a 2 axis stepper driver shield for it. The Nucleo uses the mbed platform for programming. I'm mostly a cut and paste wanna be programmer but curious how big an undertaking it would be to port TinyG to this platform.
TinyG on Nucleo F411RE
Took a 30 Second look at F441RE
You would have to start be comparing the ST part to the Atmel parts, then compare the ST drivers to the TI drivers.
IMHO, a tough job for a seasoned veteran
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