The TMC2130 may be used with 3.3 V I/Os as well as with 5 V I/Os to adapt to the CPU supply voltage. Connect a supply voltage to VCC_IO accordingly. For noise filtering use a 100 nF capacitor to ground. SPI is best for on-PCB wiring. The power supply terminals should be filtered with 100 nF capacitors as a good practice. In case VSA uses the same supply voltage as VM, the additional capacitor C4 at VSA may be left off. Sense resistors define the motor current. A variant design without sense resistors is possible for space and cost critical applications.