Since using 5 UARTs at the same time on a Pi 4 is apparently not possible, is there any reason why 4 UARTs plus either an i2c or SPI connection at the same time (one or the other) would not work?

  • 1
    The reason you can't use 5 UART is the lack of GPIO pins which are not used for some other purpose. If you study my Answer to your earlier question you should be able to pick pins enabling you to use I²C
    – Milliways
    Aug 26, 2020 at 23:04
  • 1
    Note UART 2 is unusable (at least without impact on the Pi functionality. Unfortunately much of this is undocumented.
    – Milliways
    Aug 26, 2020 at 23:10
  • @Milliways. Is that the case if I am not using CTS/RTS on any of the UARTs? I just have two pins enabled for each UART. Bluetooth, SPI, i2c are all disabled. I am also not using the gpio-fan overlay. Nor infrared.
    – YWE
    Aug 27, 2020 at 19:52


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.