Are you using Kingston SD cards? Those are notoriously bad.

Multiple block write SD card command stops because the card is busy way too often and writing constant 192 kB/s is impossible without big write buffer from small MCU. Burst speeds can be higher.

Sandisk, Transend and Lexar work much better and bigger and faster are doing their cleanups with much saner way.

Hello!

I'm designing add-on card. My feature list is quite short:

• Measure chamber temperature
• Measure VIN voltage
• Measure total power usage from energy meter
• Control chamber lightning

Those features are pretty much done. Now it is only task to hook up with Duet. I'm using Maestro version.

I think SPI is way to communicate. But what device to emulate on my MCU? And how to see those measurements on DWC?