nRF9160 DK UART Connection with External MCU

[Hamza_HK]

Hi, 

we have a nRF9160 DK where we have uploaded the AT_CLIENT example on. Have tested the board and it works fine, able to send AT Commands and join to the network etc...
Now we want to communicate with the nrf9160 modem through UART with an external MCU.

How can we connect the external MCU with the nrf9160 board through UART?

We have looked through the forum and the user manual but we were not successful with achieving our goal. We have also tried this example to establish serial communication with the nrf9160. 

The external MCU is a nrf52840. 

Would appreciate any help! 


Best Regards,
Hamza

[Sigurd]

Hi,

Steps if you are using nRF9160 DKs that is older than v.0.15.0:

The board-controller FW that is on the nRF52840 on the nRF9160DK, will route the nRF9160 pins P0.00, P0.01, P0.14, and P0.15 to the Segger/programmer chip's virtual com port, but you need to route these pins to the header. Take a look at Martin's post here on how to do that: https://devzone.nordicsemi.com/f/nordic-q-a/45476/connecting-uart1-to-a-periph-on-nrf9160-dk/178988#178988

The post is a tiny bit outdated on the names, the the target board for the nRF52840 on the nRF9160DK is now called nrf9160dk_nrf52840, and the config you need to set to route the pins P0.00, P0.01, P0.14, and P0.15, to the header is called CONFIG_BOARD_NRF9160DK_UART1_ARDUINO

In the post a pre-compiled board controller with this configuration is also found, named board_controller_uart1.hex , flash it to the nRF52840 on the nRF9160DK. (remember to set programming switch to nRF52 when you do this)

--

If you are using nRF9160 DK v0.15 then all GPIOs are now always connected to headers.

If you are still having issues, then try to use some other pins on the nRF52840DK.

Let me know how it goes.

BR,

Sigurd