BLE_APP_UART (Nordic UART Service) example not working as expected

RE: BLE_APP_UART (Nordic UART Service) example not working as expected

Einar Thorsrud — Mon, 06 Aug 2018 07:55:50 GMT

Yes, you can enable pull with nrf_gpio_cfg_input(). It does not go in sdk_config.h, but in your implementation (some .c file), for example right after you have initialize the UART driver using nrf_drv_uart_init().

RE: BLE_APP_UART (Nordic UART Service) example not working as expected

Watermelon — Fri, 03 Aug 2018 17:55:03 GMT

Yes the UART Rx pin is floating!

Would I enable the internal pullup like this?

nrf_gpio_cfg_input(8, NRF_GPIO_PIN_PULLUP);

Where should I put this line of code? In sdk_config.h?

RE: BLE_APP_UART (Nordic UART Service) example not working as expected

Einar Thorsrud — Fri, 03 Aug 2018 07:40:01 GMT

I see. Can you hook up a debugger and see if any APP_ERROR_CHECK has been hit? It could for instance be that you are getting a NRF_DRV_UART_EVT_ERROR or similar if you have a floating UART RX pin. If that is the case, then a pull-up might be a good idea (either by enabling the internal pull-up resistor on that GPIO pin or by using a external pull-up resistor).

RE: BLE_APP_UART (Nordic UART Service) example not working as expected

Watermelon — Thu, 02 Aug 2018 15:45:52 GMT

The LF xtal is connected. I tried changing NRF_SDH_CLOCK_LF_SRC 1 and NRF_SDH_CLOCK_LF_ACCURACY 1 in the sdk_config.h file anyway but it didn't work.

I am taking into account the that the LEDs and buttons are connected to different GPIO pins on the SparkFun board. The ble_app_hrs and ble_app_hrs_c codes work fine, but not the ble_app_uart and ble_app_uart_c.

RE: BLE_APP_UART (Nordic UART Service) example not working as expected

Einar Thorsrud — Thu, 02 Aug 2018 09:05:44 GMT

Hi,

The precompiled .hex files in the SDK may not work on the SparkFun nRF52832 Breakout, for a few reasons:

Referring to the schematics of the board, you need to make sure that you have the JP4 and JP5 enabled so that the LF xtal is connected. If not, the precompiled firmware from the SDK will hang when initializing the SoftDevice, waiting for the crystal to start. (Alternatively, you can modify the projects sdk_config.h so that you set NRF_SDH_CLOCK_LF_SRC to NRF_CLOCK_LF_SRC_RC.)
Additionally, the LEDs and buttons etc. are connected to different GPIO pins on the SparkFun board than on the nRF52 DK. You need to adjust this so that it reflects the HW you are using. You can for example make a board file for your board, as instructed here.