I2S with TMC in Marlin

[petervanderwalt]

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Hi!. I am experimenting with TMC5161 drivers, on a breadboard setup running an ESP32 with the I2S expanders running Marlin

I have just about everything else working, i can control dumb drivers just fine, but I don't seem to be getting the CS pin to switch for spi transactions to the TMCs.

Verified with a scope, activity on SCK and MOSI, but CS just stays high. Do you know if its possible to use on of the I2S expansion pins as a CS pin for the Trinamics (no spare GPIOs on the ESP32 (I know Esp32_Grbl can use the I2S pins as CS pins for TMC)

M122 reports ALL HIGH so I know its a comms issue, and not seeing CS go low at the start of the transaction makes me suspicious of whether I can use I2S CS pins in Marlin?

[teemuatlut]

The driver itself only cares about the voltage level. You can drive the CS pin with a manual switch if you want. As you said, the ESP32 GRBL project makes use of the I2S for this purpose so there is no technical limitation but I don't think it has been implemented in Marlin.