TMC Stepsticks

The FluidBoard has 4 stepper driver slots that accept TMC2130 or TMC5160 stepsticks via SPI. These are ideal for smaller motors — think NEMA-17 or NEMA-23 — and are particularly useful for auxiliary axes like a tool turret indexer, a rotary axis, or a fourth axis.

For your main machine axes (the ones that actually move the gantry or carriage), you'll almost certainly want external stepper drivers that can deliver more current. The TMC slots are there for the extras.

The TMC5160 is the more powerful of the two and handles NEMA-23 motors comfortably. If you want to use a TMC stepper, we recommend using the TMC5160's.

FluidBoard

Selecting stepstick voltage

There are two switches for selecting the voltage of the stepsticks. When using TMC stepsticks, select the 3.3v position.

The 5v position is only for external drivers and can destroy your FluidBoard when used with TMC stepsticks.

If you don't install your TMC stepstick correctly, there's a high chance you destroy both your stepstick and the FluidBoard. Always double check if your pin layout matches the board.

Each switch is used for 2 stepsticks. You cannot select different voltages for individual stepsticks.

Wiring diagram not available. View SVG

Wiring

The wiring depends on the stepstick you are using. Not all TMC stepsticks use the same layout for A and B coils, and the coils are routed to the screw terminals. Even different versions of the same stepstick might use a different layout. Check your vendor for the correct pinout!

From the stepper end, you can easily determine which coil is A and B by using a multimeter and measuring the resistance. If the resistance is almost zero, the two wires are connected to the same coil. If the resistance is higher, the wires are connected to different coils. Wire two wires of the same coil to A and two wires to B.

Configuration

The YAML configuration for TMC stepsticks is as follows:

tmc_5160: # or tmc_2130:
	step_pin: i2so.16
	direction_pin: i2so.17
	disable_pin: i2so.19
	cs_pin: i2so.18
	r_sense_ohms: 0.050
	run_amps: 1.8
	hold_amps: 1.0
	microsteps: 8
	run_mode: CoolStep
	homing_mode: CoolStep

Pinout

The pinout for the 4 stepsticks is as follows:

axis: z a b c
en i2so.19 i2so.20 i2so.11 i2so.12
dir i2so.17 i2so.22 i2so.9 i2so.14
step i2so.16 i2so.21 i2so.10 i2so.13
cs i2so.18 i2so.23 i2so.8 i2so.15
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