Pinout + Powering

Pinout

General SilentStepStick Pinout of all TMC2xxx v1.x:

Pinout v1

General SilentStepStick Pinout of all TMC2xxx v2.x and TMC516x v1.x

Pinout v2

Powering

The motor supply voltage VM is a strong power supply with a high voltage. Always ensure that there cannot occur voltage spikes on power up. Further Information: Pololu - Understanding Destructive LC Voltage Spikes.

A 100uF capacitor (low ESR) near every SilentStepStick driver is recommended for best performance and for supply voltages >=24V or >=VMmax/2 1 a suppressor diode (TVS diode) for over-voltage protection.

Only after the logic supply voltage VIO is present and stable, the driver inputs (STEP, DIR, EN, CFG…) can be driven with a high level.

If the motor is running/moving, then it is not allowed to switch off the power supply. Always make sure that the motor stands still and the motor outputs are deativated on shutting down, otherwise the driver IC can get damaged (because of back EMF). An emergency stop can be realized, when the EN pin is set to VIO (high). This will switch off all motor output drivers and will put the motor into freewheeling.

SilentStepSticks with variable 3-5V logic voltage

At power-up the motor supply voltage VM should come up first and then the logic supply voltage VIO. On power-down the logic supply voltage VIO should turned off at first and then the motor supply voltage VM, because the internal logic of the TMCxxxx driver is powered from VM. To ensure the correct powering a schottky diode from VIO (anode) to VM (cathode) can be added. The v2 Protectors for SilentStepSticks include this schottky diode.

Boards with USB Power Supply: If you use a control board with USB power supply (like Arduino + RAMPS) then always ensure that the motor supply voltage (VM) is present, when you connect the board via USB. Otherwise the TMCxxxx is not powered via the internal voltage regulator and a high current can flow into VIO or the IOs and this can damage the internal logic. As safety workaround you can disconnect the 5V signal in the USB cable, so that the board cannot be powered over USB. But the better solution is a schottky diode from VIO (anode) to VM (cathode), like on the SilentStepStick Protectors v2.

SilentStepSticks with 5V logic voltage

There is no special power-up or power-down sequence needed. If the SilentStepStick is only powered with 5V (logic) then a current can flow backwards to VM. In this case it is not allowed to enable the driver (motor outputs) and no loads (e.g. fans) should be on VM (<=4V), because the current will be drawn from the logic supply VIO.


  1. VMmax is the maximum motor power supply voltage (depending on the driver) ↩︎