Ultralight N17 R1.5 - Features & Specifications

· Ben @ Mettle & Byte

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Features

Core Components

  • High Power Microcontroller: The brains of the operation is a Raspberry Pi RP2350A, providing a significant performance uplift over the RP2040 commonly used for RRF / Klipper expansion boards. On RRF, this opens up the possibility of closed-loop control (software dependent and requires a small daughter board, implementation ongoing).
  • Silent & Precise Motor Driver: Features the Trinamic TMC2240, renowned for its silent StealthChop2™ technology, SPI connectivity and precise control at up to 256 microsteps.
  • High-Current Capability: Up to 3.0A peak motor current1, providing ample power for a wide range of demanding NEMA17 stepper motors.

Connectivity

  • CAN-FD: A dedicated CAN-FD interface based on the reliable Microchip MCP2518FD controller and MCP2542WFD transceiver. All communication is handled via the RP2350’s high-speed SPI bus for maximum throughput.
  • Selectable CAN Source: For software CAN implementations, the MCP2542WFD can be jumpered directly to the RP2350. This can be used in combination with Klipper!
  • Dual-Mode Driver Communication: The TMC2240 can be controlled via UART (for drop-in compatibility with existing RRF firmware), but also exposes SPI connectivity for more advanced configuration and diagnostics. This will allow SPI compatible drivers to be written in future.
  • Jumper-Selectable Bus Termination: A simple jumper allows you to add a split 20Ω termination resistor if the board is the last device on the CAN bus.

Onboard I/O

  • Optically Isolated Inputs/Outputs: Both the endstop input and auxiliary output are optically isolated using PC3H7B optocouplers.
  • 1 x Endstop Input: A 3-pin JST-PH connector for endstops, with jumper-selectable support for both NPN and PNP sensor types.
  • 1 x Auxiliary Switched Output: A 2-pin JST-PH connector providing a ground-switched output, capable of handling up to 1.5A. Ideal for controlling servos or small fans.
  • 1 x Expansion Port: Exposes TMC2240 encoder pins, 4 x GPIO pins from the RP2350 and 3.3v, 5v, 12v and VIN for ultimate flexibility.
  • Encoder Ready: Header pins are available to connect an external encoder for future closed-loop operation.

Power & Usability

  • Wide Input Voltage: Designed to operate on a wide DC input range, from ~14V to 36V2.
  • High-Efficiency Power Delivery: A multi-stage power system featuring Texas Instruments components throughout ensures stable and efficient power for the MCU, driver, and onboard logic.
  • Onboard Diagnostics: Status LEDs for main power (VIN), MCU activity, endstop (STOP), and auxiliary output (AUX) provide at-a-glance diagnostics.
  • User Serviceability: Onboard push buttons for BOOT and RESET, along with an exposed SWD header for advanced debugging.

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  1. Active cooling required. Drive a 3010 fan using the onboard AUX header and our 3D printed fan mounts! ↩︎

  2. 36v is the absolute maximum voltage tolerated by the TMC2240 driver. Back EMF from running the motor at this voltage will cause overvoltage events! ↩︎