I make several motion controller boards and am in the final stages of releasing one based on the RP2350B. I have a previous one based on the Pico. After working with both chips, I have come to the conclusion that the RP microcontrollers are a great fit for motion control!
This is mainly due to PIO. It allows stepper motor pulse generation with fewer interrupts needed than other microcontrollers. This leads to very low jitter in the step pulse train. It also allows for a much higher step rate than comparable microcontrollers. On my forthcoming RP2350B based board, the RP23U5XBB (https://github.com/phil-barrett/RP23CNC), I can get 370K steps/S with very low jitter. Whereas, similar M3/M33 micros are considerably slower and have significantly higher jitter. You have to move up to M7 processors with significantly higher clocks rates (like iMXRT1062 at 600 MHz) to do better.
The RP2350B with 48 GPIOs is a particularly good fit as it allows 5 Axes (step, direction, enable), numerous outputs (for controlling spindles, relays, digital outputs), numerous digital inputs (encoders, limit and homing sensors), 2 UARTS, I2C and SPI (for W5500 Ethernet and microSD).
This is mainly due to PIO. It allows stepper motor pulse generation with fewer interrupts needed than other microcontrollers. This leads to very low jitter in the step pulse train. It also allows for a much higher step rate than comparable microcontrollers. On my forthcoming RP2350B based board, the RP23U5XBB (https://github.com/phil-barrett/RP23CNC), I can get 370K steps/S with very low jitter. Whereas, similar M3/M33 micros are considerably slower and have significantly higher jitter. You have to move up to M7 processors with significantly higher clocks rates (like iMXRT1062 at 600 MHz) to do better.
The RP2350B with 48 GPIOs is a particularly good fit as it allows 5 Axes (step, direction, enable), numerous outputs (for controlling spindles, relays, digital outputs), numerous digital inputs (encoders, limit and homing sensors), 2 UARTS, I2C and SPI (for W5500 Ethernet and microSD).
Statistics: Posted by phil from seattle — Fri Mar 28, 2025 9:30 pm