Arduino Uno as SPI slave

[pylon]

@arduinomegalul

I tried changing the clock div to all values but it doesn't help, any hints on what is wrong assuming the connections are correct?

As I haven't seen the code of the other side I would expect the error to be there. Or the connections are not correct.

@arduinomegalul

I tried goin in reverse now, using UNO as the master and SAMD as the slave.

Why?

@arduinomegalul

In addition to that I tried sending from SAMD21 to SAMD21 using the code that worked after lowering frequency but the slave never gets any data.

The slave code you provided in the original post won't work on the SAMD21, i won't even compile.