Raspberry Pi OS • Serial Port assignments

I have a Raspberry Pi Zero 2 W. I already setup up the serial Port at GPIO14,15 as a serial console and that is all working. I documented my steps at https://www.quietwind.net/wiki/doku.php ... aspberrypi.

Ultimately, I want to add a second serial port. But in investigating how to do that I ran into some questions that I thought you might be able to answer. In this document https://datasheets.raspberrypi.com/bcm2 ... herals.pdf on page 102 it shows the following for GPIO14,15

GPIO14 Alt0 = TXD0 and Alt5=TXD1
GPIO15 Alt0 = RXD0 and Alt5=TXD1

Similarly for GPIO32,33

GPIO32 Alt3 = TXD0 and Alt5=TXD1
GPIO33 Alt3 = RXD0 and Alt5=RWD1

So, when I looked at the GPIO alt assignments via raspi-gpioSo, it seems that GPIO14,15 is assigned to TXD1,RXD1 and GPIO32,33 is already assigned to TXD0 and RXD0. I guess I would have expected that in reverse.

Am I correct on that ?

I can see that when I log in through the serial console I am on the /dev/ttyS0 device
I can see the ttyS0 device is available but I don't see a ttyS1, which I assume would connect to GPIO32.33 since they are assigned to TSD0,RXD0.
Any pointers on how to access the serial port on GPIO32,33 from linux would be appreciated since, my ultimate objective is to get a second serial port available.

Thanks
Chris

Statistics: Posted by chriskot870 — Thu Aug 29, 2024 11:52 pm

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