Review request: low-cost dual motor controller based on Pico + DRV8316

[thomasfla]

Hi,

I’m about to design a low-cost dual motor controller for teaching purposes and would appreciate some feedback before I commit to the PCB.

The target application is a 2-DOF direct-drive arm using two GM3506 motors with integrated AS5048A encoders. The goal is to keep the cost as low as possible while still supporting closed-loop FOC with current control.

Current architecture:

• Raspberry Pi Pico or Pico 2 module
• 2 × DRV8316 (3PWM mode)
• Dual low-side current sensing
• External ADCs (based on this proof of concept: DO NOT MERGE WIP. Add support for external SPI ADC on rp2040 and rp2350 by thomasfla · Pull Request #65 · simplefoc/Arduino-FOC-drivers · GitHub)
• Shared SPI bus for encoders and DRV configuration
• Optional RS485 transceiver footprint
• 24 V supply

The target BOM cost is around €20–30 (excluding motors and encoders).

I’d be happy to get any general feedback on the schematic before I send the board for manufacturing. I’ll also post the PCB layout later for review.

If the concept works well, a future revision could use the RP2354B directly instead of a Pico module to make the board more compact and expose additional I/O.

Thanks!

[o_lampe]

I’m to lazy to check the DRV8316 datasheet, but I find it odd you put INLA-INLC to VCC?
I’d expect GND…
Also routing both nFault outputs to one pico pin is odd IMHO. I’d decouple them with a dual Schottky.
I haven’t seen nReset anywhere. Which might be nice to have, if you want to clear a fault