Can I use a Raspberry PI model B to interact directly to a router debug console (undocumented) via "screen".

TX  <-> RX
RX  <-> TX

# screen -L /dev/ttyAMA0 115200,-parenb,-cstopb,cs8 

Probable serial parameters: 115200, 8N1. Tests confirm 3.3v by following this tutorial.

The "mini UART" seems problematic because of the fixed frequency so I will disable bluetooth and use the PL011 UART via /dev/ttyAMA0.

I have read that I can also use any GPIO as TX and RX but maybe this could add some more problems since I would need to find or program a driver?

Also note that I use a custom 64Bit custom kernel/OS with the kernel configured only for this purpose. I know about USB to TTL cable and ordered one... I have some basic electronic components and tools if required but would prefer a direct connection if this is realizable.

1 Answer 1


Yes, that should work.

You could bit bang a serial link on other GPIO but as you say you would have to write your own drivers.

Another alternative is to use a USB serial dongle. You could plug the USB end into the Pi.

  • Thanks I will accept your answer if it works as is. I know about the dongle and ordered one today and then thought about the pi that I already have.
    – 01BTC10
    Jan 25, 2018 at 17:56
  • It works with "enable_uart=1" "pi3-disable-bt" and removing all the "console=xxx" from the cmdline. The mini UART printed only garbage.
    – 01BTC10
    Jan 25, 2018 at 23:25

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