From the CAN shield schematic it seems clear that the shield uses the SPI interface with chip select on pin 3 of the header. Looking at the schematic for the motor carrier, header pin 3 is identified as
IN1_M3 which then goes to pin 2 of the MC33926PNB motor control IC which drives the M3 motor outputs. The SPI lines are connected to the ATSAMD11D14A-MNT controller IC on the motor board and that has a pin labelled
SWDIO/SS which is connected to pin 7 of the header, but via a resistor
R16 which is marked
Does that mean I can use the two together as long as I don't use M3 on the motor board, or is it more complicated than that? I'm hoping to program the MKR1000 from Simulink so I'd be using the Simulink
SPIWriteRead block to communicate with the controller on the CAN shield.