Using an iot2050 basic, updated at the last image (V01.04.01-0-gb5963ab-dirty).

We tried to configure the port, initially using the other example in this forum like

https://support.industry.siemens.com/forum/ie/en/posts/how-to-find-out-if-x30-com-port-switched-to-rs485-successfully/301057/?page=0&pageSize=10

Which suggest to use

switchserialmode ttyuart -D /dev/ttyS2 -m rs485

This is an old sintax and we noticed the modern one is

switchserialmode -m rs485

I already reported that in https://github.com/siemens/meta-iot2050/issues/591 and the developer confirmed the syntax changed.

So we used the new one, and looks like it worked, as confirmed from doing

switchserialmode -d
rs485 active-logic(high)

The code that we tried to use is in

https://gist.github.com/RoyBellingan/d9b719a17578c65edd72a06a66596a17

But we are not able to find any life sign coming out from the pin 1 and 2... (according to page 66 in https://support.industry.siemens.com/cs/ww/en/view/109779016)

While checking the source code for switchserialmode in https://github.com/siemens/meta-iot2050/blob/master/recipes-app/switchserialmode/files/src/switchserialmode.c#L87

and this ttyuart_ops points to this

https://github.com/siemens/meta-iot2050/blob/950a0aaa017e1cd39e4a1eb535b2344325209611/recipes-app/switchserialmode/files/src/serial/omap_8250.c#L146

So, I am quite inclined to think this is the actual port we have to use ?