Pinout and Powering

Further information about the pin functions and power supply. Note, the component side of the PCB is the bottom.

Pin Functions

Pin Function
Power Supply
GND Ground
VM Motor Supply Voltage
VIO Logic Supply Voltage
Motor Outputs
M1A Motor Coil 1
M1B Motor Coil 1
M2A Motor Coil 2
M2B Motor Coil 2
Control Inputs
STEP Step-Signal Input
DIR Direction-Signal Input
TMC2100
EN Enable Motor Outputs: GND=on, VIO=off, OPEN=Auto-Power-Down
CFG0 Chopper Off Time TOFF: GND=140tclk, VIO=236tclk, OPEN=332tclk
CFG1 Step-Configuration
CFG2 Step-Configuration
CFG3 Current Setting: GND=int, VIO=int, OPEN=ext
CFG4 Chopper Hysteresis HEND: GND=5, VIO=9, OPEN=13
CFG5 Chopper Blank Time TBL: GND=16, VIO=24, OPEN=36
DIAG0 Diagnostics Output 0
DIAG1 Diagnostics Output 1
VREF Analog Reference Voltage
TMC2130 (SPI_MODE=1)
EN Enable Motor Outputs: GND=on, VIO=off, OPEN=Auto-Power-Down
SDO/CFG0 Serial Data Output (SPI)
SDI/CFG1 Serial Data Input (SPI)
SCK/CFG2 Serial Clock Input (SPI)
CS/CFG3 Chip Select Input (SPI)
DCEN/CFG4 dcStep Enable Input (GND=off)
DCIN/CFG5 dcStep Gating Input
DIAG0 Diagnostics Output 0
DIAG1 Diagnostics Output 1
TMC2208
EN Enable Motor Outputs: GND=on, VIO=off
MS1 Step-Configuration
MS2 Step-Configuration
PDN UART and Auto Power Down Control: GND=on, VIO=off
CLK Clock Input
DIAG Diagnostics Output
INDEX Index Output
VREF Analog Reference Voltage

TMC2100 Step-Configuration

CFG2 CFG1 Steps Interpolation Mode
GND GND 1 - spreadCycle
GND VIO 12 - spreadCycle
GND OPEN 12 1256 spreadCycle
VIO GND 14 - spreadCycle
VIO OPEN 14 1256 spreadCycle
OPEN VIO 14 1256 stealthChop
VIO VIO 116 - spreadCycle
OPEN GND 116 1256 spreadCycle
OPEN OPEN 116 1256 stealthChop

TMC2208 Step-Configuration

MS2 MS1 Steps Interpolation Mode
GND GND 18 1256 stealthChop2
GND VIO 12 1256 stealthChop2
VIO GND 14 1256 stealthChop2
VIO VIO 116 1256 stealthChop2

Other modes and options can be set via UART (see TMC2208 Configurator).

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 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 TMC2xxx 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.

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.