I'm successfully printing to the UART1 com port at baud rate 115200, but I have a peripheral I plan to connect that requires 9600. What is the proper way to go about this? Are there multiple places this needs to be changed or is there one config I can set?
I did try changing the config here:
zephyr\ext\hal\nordic\nrfx_config_nrf9160.h
but it didn't appear to work as I expected
Thank you!
Ok that's strange, your build file clearly states that the speed of UART1 is 9600. I confirmed this with my own custom PCB by changing my overlays to 9600 and my UART0 now runs at 9600 Baud. It should be that simple. My analyser can't detect the baud rate now at 115200 until I go down to 9600 (and it even prints slower 
)
Try this, reset the .dts files and add two overlay files, one to spm named nrf9160_pca10090.overlay and the other in your project folder (at the same level as prj.conf) named nrf9160_pca10090ns.overlay.
In both place this, but tweak it to reflect your UARTs:
/* Needed to get NRF_UARTE2 and NRF_PWMn defined. */
&uart0 {
status = "ok";
};
&uart1 {
status = "ok";
current-speed = <9600>;
tx-pin = <22>;
rx-pin = <23>;
rts-pin = <30>;
cts-pin = <31>;
};
&uart2 {
status = "ok";
};
&pwm1 {
status = "ok";
};
&pwm2 {
status = "ok";
};
&pwm3 {
status = "ok";
};
NOTE: the above will clear UART0 unless you define it in the same manner as UART1, leaving anything as 'status= "ok" ' will clear it's configuration.
Then rebuild both spm and your project folder, remembering to build spm with the secure board and the project with the non-secure board (spm -> -DBOARD=nrf9160_pca10090 | project -> -DBOARD=nrf9160_pca10090ns).
Ok that's strange, your build file clearly states that the speed of UART1 is 9600. I confirmed this with my own custom PCB by changing my overlays to 9600 and my UART0 now runs at 9600 Baud. It should be that simple. My analyser can't detect the baud rate now at 115200 until I go down to 9600 (and it even prints slower )
Try this, reset the .dts files and add two overlay files, one to spm named nrf9160_pca10090.overlay and the other in your project folder (at the same level as prj.conf) named nrf9160_pca10090ns.overlay.
In both place this, but tweak it to reflect your UARTs:
/* Needed to get NRF_UARTE2 and NRF_PWMn defined. */
&uart0 {
status = "ok";
};
&uart1 {
status = "ok";
current-speed = <9600>;
tx-pin = <22>;
rx-pin = <23>;
rts-pin = <30>;
cts-pin = <31>;
};
&uart2 {
status = "ok";
};
&pwm1 {
status = "ok";
};
&pwm2 {
status = "ok";
};
&pwm3 {
status = "ok";
};
NOTE: the above will clear UART0 unless you define it in the same manner as UART1, leaving anything as 'status= "ok" ' will clear it's configuration.
Then rebuild both spm and your project folder, remembering to build spm with the secure board and the project with the non-secure board (spm -> -DBOARD=nrf9160_pca10090 | project -> -DBOARD=nrf9160_pca10090ns).
I am referring to this when I refer to SPM
https://github.com/NordicPlayground/fw-nrfconnect-nrf/tree/master/samples/nrf9160/spm
This is your Secure Partition Manager. It must be rebuilt each time you alter the dts. When you build here, you are building for the secure part of flash. When you build in your projects, you are building for the non-secure region of flash and that's why both need overlays and their own dts files.
Did you see my last message about making sure your UART pins are configured correctly in your files? Your TX and RX pins are the same as what I originally shared and it's unlikely that they were also your intended pins for UART1 
Glad to hear you got it working. Happy coding! 