General discussion • Clarification on using PL011 UART

I have a Pi 3 model B+ and want to connect to it using a USB to serial adapter and the GPIO pins for UART Tx/Rx.

Reading the documentation however leaves me a bit confused as to what config options I should be setting.
This page says that UART0 is the PL011 and UART1 is the mini UART, then says that the primary one - the one that's on the GPIO pins - is UART1.

So my first question is can I swap the primary and secondary so that the PL011 is on the GPIO pins?

Then there is this which talks about the "enable_uart" setting in config.txt.
I assumed that setting it to 1 would enable UART (after all, it is literally called that) but that page just says it enables the primary one, which is the mini UART on Pi 3 and 4.
Note too that I do not want the clock frequency reduced, hence why I want to use the PL011 and not the mini UART.

So further questions - if I want to use the full PL011 and not the mini UART, should I set enable_uart to 1 or 0? Additionally, what is the status of the secondary UART, is it available regardless of the enable_uart setting?

Lastly, I went into raspi-config and said yes to both the questions regarding serial interface ("Would you like a login shell to be accessible over serial" and "Would you like the serial port hardware to be enabled"). Is this correct to do what I want?

Statistics: Posted by xtal256 — Mon Apr 08, 2024 2:05 am

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