BLE communication between a nRF52 DK board and a nRF9160 DK board

[Timothy]

I am running V2.5.0 SDK. I have a nRF52 DK board that is running the V2.5.0/nrf/samples/Bluetooth/peripheral_uart application. It is working beautifully. I have nRF Toolbox installed on my iPhone. I can connect to the nRF52 DK Bluetooth running the NUS UART service. I can send text strings back and forth from my iPhone to the nrf52DK baord. We have been using the nRF9160 processor for years and we are very comfortable with its operation. We have never used the Bluetooth feature on the nRF9160. I have a nRF9160 dk board that I would like to implement the NUS UART Bluetooth connection like I have running with the iPhone using nRF Toolbox. I want an application on the nRF9160 to search for BLE devices advertising the UART service. I want to connect to that BLE device and be able to send text string back and forth like I can do on my iPhone. I tried the "Bluetooth central UART" but it does not support the nRF9160 as a valid board.

what do I need to do to implement a simple BLE connection between the nRF52DK and the nRF9160DK so I can send text strings back and forth simulating a UART.I have not used any BLE functions until we received the nrf52DK board. I am sure it is operator error. Our application depends on the BLE capability to talk between an nRF52 and a nRF9160. any help would be greatly appreciated.

[Vidar Berg]

Timothy said:

ASSERTION FAIL [err == 0] @ WEST_TOPDIR/zephyr/subsys/bluetooth/host/hci_core.c:338
command opcode 0x0c03 timeout with err -11

The assertion displayed when you programmed the gateway sample indicates that the Bluetooth host on the nRF9160 is failing to communicate with the Bluetooth controller on the nRF52840. Did you remember to program the controller?

Vidar Berg said:

Edit: forgot to add that you need to program the LP HCI UART sample to the nRF52840 on the board for BLE connectivity: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/2.5.0/nrf/samples/cellular/lte_ble_gateway/README.html#programming-the-sample 

Do you know what was done differently this time as you managed to build the LTE_BLE_GATEWAY without the errors mentioned earlier? I can't see any reason why you would be able to build this sample, but not the one I uploaded, given that the BLE configurations should be the same in both cases.

[Timothy]

I think I understand what you are trying to say. The nrf9160 has a programmed flashed in that device. what is that program? the nrf%2840 on the DK board has a separate program flashed in that part. What is that program and how do I program the nRF52840 on the nRF9160 DK board? Thanks for your help.

[Vidar Berg]

The nRF9160 runs the Bluetooth host (i.e., the upper layers of the Bluetooth stack) and the application code, while the nRF52840 chip on the same nRF9160 DK board is supposed to run the Bluetooth controller firmware (Bluetooth: HCI low power UART) to enable the BLE connectivity since the 9160 doesn't have its own BLE RADIO.

The nRF52840 must be programmed separately with the FW build from the Bluetooth: HCI low power UART project.

[Timothy]

Vidor thanks for the quick response.

so is C:\Nordic1\v2.5.0\nrf\samples\bluetooth\hci_lpuart the project that gets flashed into the nRF52840 on the nRF9160 DK board? I will flash that into the nRF52840 using the SW10 switch in the nRF52 position.

what application is flashed into the nRF9160? is that the centarl_uart you sent me that I cannot get to build yet or some other from the list of samples?

[Vidar Berg]

No problem. Yes, "C:\Nordic1\v2.5.0\nrf\samples\Bluetooth\hci_lpuart" is the project you want to flash to the nRF52840.

Timothy said:

what application is flashed into the nRF9160? is that the centarl_uart you sent me that I cannot get to build yet or some other from the list of samples?

Correct. The central UART sample I provided should be programmed to the nRF9160. If everything works it should try to connect to your nRF52 DK board programmed with the Peripheral UART example.