Using TMCM-035 SPI Interface

[FritzFM]

I am using the TMCM-035 with SPI Interface and have connected it
in the Loop with TMC428. I see the clock signal not reaching low level.
It seems to have a pull up resistor on board. I could not find any
information about the input in the TMCM-035 Manual. Is there
additional information ?

[Olav Kahlbaum (TRINAMIC)]

When using the TMCM-035 in SPI mode the most important thing is that pin 22 (SDEN which means Step/Dir Enable) is tied low to turn off step/direction mode as otherwise the CPU on the TMCM-035 will interact with the SPI lines which will definitely lead to unclear signals on the SPI bus.
Also, pin 19 must be high to select SPI mode.
The SPI pins of the TMC249/TMC239 used on the TMCM-035 have internal pull-up resistors, but it is still possible to pull them low without any problems (e.g. when using a TMCM-301 or TMCM-341 together with a TMCM-035 it is just the same: a TMC428 is connected directly to the TMCM-035 (resp. to the TMC249/TMC239 used on it)).