Making UART0 or UART1 externally accessible for serial_lte_modem

[Mr.Newlove]

I am working on a custom board for the nRF9160 and currently have a DK and a thingy.

I need to make a serial interface available on the DK, thingy and a custom board I am working on for serial AT commands. I would prefer for it to be UART1 so I can still use the USB interface.

A few weird things I have run into, I tried to edit "nrf9160dk_nrf9160ns.overlay": (formatting gets screwed up if you try to insert as code)

&uart2 {
compatible = "nordic,nrf-uarte";
current-speed = <115200>;
status = "okay";
tx-pin = <10>;
rx-pin = <11>;
rts-pin = <12>;
cts-pin = <13>;
hw-flow-control;
};

I have tried changing pins and buadrate to no effect, even after reloading the project in SEGGER, but if I do the same for UART1/0 but still nothing.

When I goto make my own custom board how do I actually go about selecting pins for the AT command UART?

Edit:

I tried this solution: https://devzone.nordicsemi.com/f/nordic-q-a/45941/nrf9160-asset-tracker-configure-uart but the project gets errors when I try to open it

There was another one I tried, but I can't find it right now. Was to do with some kind of Arduino flag.

[Albrecht Markus Schellenberger]

Hello,

thanks for the feedback and the video!

I’m honestly not quite sure what your main goal is. But anyway, the purpose of the Serial LTE modem application is to use the nRF9160 as a stand-alone LTE modem. So, what you could do is to flash the application to your DK and then connect an external MCU to it, as described in this section.

On the external MCU, you have to run your own application that sends AT commands which will be received via the UART2 on the DK. My recommendation is to get that to work first, before starting to change the pin configurations. That would be a way to verify that the system is generally working.

And example of an external application is given here.

I hope this will help you!

Regards,

Markus

[Mr.Newlove]

Hello Markus,

Video showing the embarrassing little I had to do to get it working but somehow screwed it up for over a week there. https://youtu.be/fhetw20m3ME

I don't know why I am having such a hard time with zephyr and documentation for the configuration of this chip.

Thanks for your help,

Kyle