[Feature Request] Support MKS SKIPR board (canbus port not working via uart PI to MCU)

Hello.

Makerbase make a new board - SKIPR, it contain Rasbery and MCU STM32F407VET6
That’s a link: github MKS-SKIPR

This MCU (STM32F407VET6) have a 2 CUNBUS ports, SKIPR board uses CAN2 on PB12 PB13, and Raspberry communicate with MCU via UART1 - PA9 PA10 directly with traces on pcb. It different like BTT or Mellow boards, communicate with MCU via usb onboard traces.

I use a MKS THR42 CANBUS board on toolhead and CANBUS port on SKIPR board for communicate - this setup works now, but weird connection! In the same board i use usb port on PI side to connect usb on MCU side, internal communication between Pi and MCU via UART unable to use.

Klipper don’t have compile option “communicate with MCU via serial on pins … CANBUS MCU communication on pins …” simultaneously.

Now i compile firmware for MCU like CANBUS bridge. It requaest USB connection. It looks weird, i need use additional usb port to connect board itself (loop usb Pi to MCU side)

I (and many owners of SKIPR board on this forum) wants to communicate PI with MCU side via onboard UART and MCU communicate with CANBUS to toolhead boards.

Please add to firmware compiler this option (not only usb-can bridge mode like now). Now i need choice between communicate PI to MCU via onboard UART without possible to use onboard CANBUS, or communicate PI to MCU via USB loop cable withot internal onboard UART but with internal CANBUS port (canbridge). Need something like UART CANbridge, not only USB.

Raspberry PI <-UART-> MCU <-CANBUS-> THR42 (toolhead)

Hello @furry-cheetah !

What Klipper hardware are you using, and what OS?

Makerbase SKIPR board.

It have Raspberry Pi and MCU chip STM32F407VET6 on the same board and internal communication with UART between each other.

Board photo

On toolhead use MKS THR42 (canbus board)

Toolhead photo

OS: Armbian 22.05.0-trunk with bleeding edge Linux 5.16.20-rockchip64
Klipper: v0.11.0-197 (latest one)

Original topic about canbus on SKIPR starts here

32 bit OS or 64 bit OS?

Operating System: Debian GNU/Linux 10 (buster)
Kernel: Linux 5.16.20-rockchip64
Architecture: arm64

Armbian 22.05.0
Klipper: v0.11.0-197

In Klipper firmware compiler (for mcu STM32F407VET6) no option to simultaneously communication via UART and CANBUS, only one at once. Or Raspberry PI to MCU via UART, or MCU to CANBUS bridge, but need use additional usb cable to connect MCU to Raspberry.