Never loses a step
A 20 kHz position loop tracks the shaft through the on-board AS5600. A blocked axis is caught as a stall and stopped, never silently shifted.
Drivers
Tercio S1
Closed-loop stepper driver
Bolts to the back of a NEMA 17 and closes the loop: a 12-bit encoder under the board reads the shaft, a 20 kHz position loop corrects every step, and CAN-FD connects up to 127 axes on one bus.
Launch price soon
Tercio S1 goes on sale 1 December 2026. We’ll email you the moment it does.
- Open-source firmware
- Free browser control panel
- Python and C++ libraries
- Shipping calculated at checkout
Tunes itself
Auto-tune runs the axis faster and faster until it slips, then keeps the fastest speed and acceleration that passed three times.
Quiet by default
The TMC2209 runs StealthChop at low speed and switches to SpreadCycle when the motor needs the torque.
Homes without switches
Home against a limit switch, or gently into a hard stop with reduced current. No switch needed.
Drop-in step/dir
Configure once over CAN, then drive it from any 3.3 V step/dir controller while it keeps the loop closed.
Open firmware
GPL-3.0 firmware built with PlatformIO, plus Python and Arduino C++ libraries and a browser control panel.
Specifications
The details.
In the box
- Tercio S1 driver board
Control
- Processor
- STM32G431, Arm Cortex-M4F at 170 MHz
- Position loop
- 20 kHz, trapezoidal motion planner
- Procedures
- Encoder calibration, homing, speed-limit auto-tune
- Protection
- Stall detection, over-temperature shutdown, command timeout
Motor driver
- Driver
- Trinamic TMC2209
- Current
- Up to 1.77 A RMS per coil (2.5 A peak), set in software
- Microstepping
- Up to 1/256, StealthChop and SpreadCycle
- Motor
- Bipolar stepper, NEMA 17 mounting
Feedback
- On-board encoder
- AS5600, 12-bit (4,096 counts per turn), on the underside
- External encoder
- AS5048A (SPI, 14-bit) or AS5600 (I²C), 12-pin connector
Interfaces
- Bus
- CAN-FD, 500 kbit/s arbitration and 2.5 Mbit/s data
- Nodes
- Up to 127 per bus, 120 Ω termination by jumper
- Step/dir
- STEP, DIR and EN inputs, 3.3 V logic only
- Inputs
- Two limit or home switch inputs
Physical
- Supply
- 12–28 V DC
- Board
- 38 × 38 mm
- Connectors
- Screw terminals: 3.5 mm for power, 2.54 mm for motor, CAN and switches. JST PH (step/dir), JST PHD 12-pin (external encoder)
