I am working on a project and I am trying to connect a GPS receiver to the RPi through uart and a TNC-Pi (Terminal Node Controller) Both of the instructions want me to use "ttyAMA0" and move bluetooth to "ttyS0". It is imperative that I do not change the TNC at all, so I will need to change the port for the GPS. How do I do this?

TNC-Pi instructions go to pg 14

Adafruit Ultimate GPS for RPi UART


After doing a little research I can use a SPI-to-UART chip, but still have no idea as of yet how that is going to work

1 Answer 1


The Pi3 has only two accessible GPIO (14/15) which may be used as a UART and provide one serial link.

You can use other GPIO as a software UART if you know how to write software and are pretty competent doing so.

The alternative is to use serial to USB dongles.

  • The serial usb dongles will not work for what I am trying to do. It has to fit in the large Smarti Pi hat cover and be portable. Where can I find infomation on making software UART's?
    – KM4HPK
    Oct 31, 2017 at 23:00
  • You should add that restriction to your question. My pigpio has support for software serial links. I reiterate it requires a familiarity with writing software.
    – joan
    Nov 1, 2017 at 1:39

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