Using two UART in nrf51822

RE: Using two UART in nrf51822

Håkon Alseth — Wed, 18 Dec 2019 13:12:44 GMT

Please see the example \nRF5_SDK_12.3.0_d7731ad\examples\peripheral\uart.

In main.c, there's a uart init function call:

....
    const app_uart_comm_params_t comm_params =
      {
          RX_PIN_NUMBER,
          TX_PIN_NUMBER,
          RTS_PIN_NUMBER,
          CTS_PIN_NUMBER,
          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);
....

You can change the define (in pca10028.h directly, or by adding your own board: https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sdk5.v12.3.0/sdk_for_custom_boards.html?cp=7_5_8_1_5) or give the function a pin-number of choice.

Kind regards,

Håkon

RE: Using two UART in nrf51822

Nidhi — Wed, 18 Dec 2019 10:52:54 GMT

Can you attach a example of how to assign RXD and TXD pins to GPIO pins.

RE: Using two UART in nrf51822

Håkon Alseth — Wed, 18 Dec 2019 09:41:13 GMT

Hi,

The nRF51x22 only has one UART peripheral, as per the product specification. RXD and TXD can be assigned to any unused GPIO of your choice.

If you need a second UART, you have to implement a bit banged UART (a software implemented uart using GPIOs). Unfortunately, we do not have any implementations of this available, but it is however been discussed on the forum before. Try searching for "bit bang uart" and you should find some threads on this.

Note that nRF52840 has two hardware UARTE peripherals, so you could move to that device if your application require this.

Kind regards,

Håkon

RE: Using two UART in nrf51822

Nidhi — Wed, 18 Dec 2019 09:01:25 GMT

two uarts in ble_peripheral -> ble_app_uart example.