Ender3v2 board to RPI with screen connector

While I would recommend doing this only when you have the proper experience, in a nutshell you need:

  1. Identify the RX / TX pins of the printer board
  2. Match these pins to the Communication interface setting during make menuconfig
  3. Build and flash the new firmware
  4. Prepare your SBC to accept serial connections
    • Can involve quite some research
    • Might depend on the Linux distribution
    • Needs some shenanigans with boot configs etc.
  5. Identify the proper GPIO pins on the SBC, which can equally be tricky, especially, e.g. on a RPi 3
  6. Connect the board and the SBC
    • RX to TX
    • TX to RX
    • GND to GND
  7. Set the correct /dev/... path in the printer.cfg. Refer back to No 4 and 5 as the same applies. Usual suspects are /dev/ttyAMA0, /dev/ttyS0, /dev/serial0
  8. Restart Klipper and pray


  • On OS level (e.g. dmesg) you will not see if a proper connection exists or not. A UART connection is not plug’n’play and does not announce itself to the OS
  • Some diagnosis could be done with the setserial command
  • Messing up the connection or shorting some GPIO pins, especially when the SBC is powered up, can easily kill it.