@dc42 I get why the IO expander is needed for attachment to an existing maestro etc... but Given that both the ESP32 and the STM32 have plenty of GPIO's is there an easy way to bypass it and wire IO's directly? Or too much hassle ? Any downsides to using I2C over direct in this situation?

plenty of I2C and SPI buses on the STM32F7 and the ESP32 ; so shouldn't be an issue there.

The limits are likely analogs (only 6 useable on the ESP32)

@phaedrux said in Duex5 as RAMPS Like breakout board for $MCU's?:

Klipper

Yes - but I am after something more contained to develop marlin targets for.

Hi there ;

I have been eyeing up the schematics of the Duex5 as a potential breakout for drivers/heatbed/sensors. Have been trying to find something RAMPS-FD like for 3.3v MCU's that I can easily attach to various MCU boards for testing.

What (if anything) is missing off the Duex5 that I would need.

MCU targets in Mind are:

ESP32
STMF7 (Nucleo/OpenSTM)

If it's really just a matter of Hooking Duponts into the 50Pin connector the Duex5 seems like an ideal choice for Prototyping development from random MCU boards.

Would like to know if there are any gotcha's here?