NRF9160DK-NRF52840 MCU Interface pins

[ANDRES SANDOVAL]

Hi everyone,

I am a beginner developing projects with nordic boards and currently am using the NRF9160DK. I just made an application through Ble MCU (nrf52840) and I want to send some data to NRF9160DK to be able to send the data to the NRF cloud. Watching the schematics of the development kit, I saw some common pins named NRF91_IF and NRF52_IF, so I supposed that those pins are used to communicate both MCUs, but I am not clear on how to do that. There is a protocol for that?

Thanks.

[Simon]

If you take a look at nRF9160 DK board control and the nordic,nrf9160dk-nrf52840-interface binding, you can see that the following GPIO pins can be connected together on the nRF9160 DK:

| nRF9160 | | nRF52840 |
| P0.17 | -- nRF interface line 0 -- | P0.17 |
| P0.18 | -- nRF interface line 1 -- | P0.20 |
| P0.19 | -- nRF interface line 2 -- | P0.15 |
| P0.21 | -- nRF interface line 3 -- | P0.22 |
| P0.22 | -- nRF interface line 4 -- | P1.04 |
| P0.23 | -- nRF interface line 5 -- | P1.02 |

Check out this comment to see how to connect these together:

To achieve this, set the status of respective 
devicetree nodes in the firmware for the 
nrf9160dk_nrf52840 board to "okay":
- `nrf_interface_pins_0_2_routing` to enable lines 0-2
- `nrf_interface_pins_3_5_routing` to enable lines 3-5

It can be done by adding these to the overlay file of the nrf52840, or simply include the whole file nrf9160dk_uart1_on_if0_3.dtsi (will configure uart1 pins as well), like it's done in hci_lpuart/boards/nrf9160dk_nrf52840.overlay 

I have not tested this myself, so please let me know if it works or not

Best regards,

Simon

[ANDRES SANDOVAL]

Hi Simon, thanks for your answer.

I used the Low power UART example and as you said, I added the pins modification to the overlay, for the moment I am working on the UART by polling between the NRF9160 and NRF52840 on the development kit and also the Thingy91.

Thanks.