RE: NRF52 UART initialisation issue/crash due to low state on pin

MartinBL — Tue, 12 Sep 2017 15:10:47 GMT

So the problem is that the RX pin is floating and picking up noise (or just being pulled low)? It is possible to configure the RX pin as 'disconnected' by setting the PSELRXD register to 0xFFFFFFFF. Maybe that will help. If you are using the drivers and libraries in the SDK you can do it like this:

const app_uart_comm_params_t comm_params =
  {
      RX_PIN_NUMBER,
      TX_PIN_NUMBER,
      RTS_PIN_NUMBER,
      UART_PIN_DISCONNECTED,
      APP_UART_FLOW_CONTROL_ENABLED,
      false,
      UART_BAUDRATE_BAUDRATE_Baud115200
  };

APP_UART_FIFO_INIT(&comm_params,
                     UART_RX_BUF_SIZE,
                     UART_TX_BUF_SIZE,
                     uart_error_handle,
                     APP_IRQ_PRIORITY_LOWEST,
                     err_code);

APP_ERROR_CHECK(err_code);

But I suppose if you know what you are doing you can just write to the register directly after having initialized everything the usual way.