Micro-ros Transport (CAN vs Serial)

[snaens]

Stefan May uses CAN for his stuff, agreed it's a great protocol, however support is lacking, especially in (micro) ROS.
In contrast, Serial, the default micro-ROS protocol, has fantastic support.

This leaves me with the following 2 Options:

CAN:

• - Means I have no Micro ROS → more complex, no micro_rosso
  • However Easy-CANopen and ros2_canopen exist
• = (alternatively one could use Cyphal, but the Cyphal-ros2 bridge is unmaintained)
• + has ros2_control support - this would be perfect for motor control

Serial:

• - No bus architecture - we are forced into a star network, probably using a rp2040 as a UART hub using all serial ports
• + Micro ROS
• + generally easier to work with

[snaens]

Turns out I was wrong, CAN is totally built into Micro-XRCE, the micro-ROS agent, however only CAN-FD
here's an example

can2040 can't do CAN-FD :(

Solution for future: make microros transport using mcp25xx CAN-FD variant, as they are very well-known modules
Theoretically this could become a microcontroller-agnostic transport, as SPI is basically the same on all MCUs.

More reading:

• PR Agent
• PR Client note: only mentions CAN, no FD
• this issue demonstrates how it should look
• example custom CAN transport for STM32