nRF51822之app_button控制uart的开启和关闭

为什么要使用app_button来控制uart的开启和关闭

还是先上datesheet中uart开启的时候需要HFCLK，需要消耗大量大电流。所以在我们需要的时候需要通过io来通知nrf51822开启uart的功能。

主要是上个app_button添加

static void button_handler(uint8_t pin_no, uint8_t button_action)
{
    if(button_action == APP_BUTTON_PUSH)
    {
        switch(pin_no)
        {
            case BUTTON_1:
            NRF_UART0->ENABLE        = (UART_ENABLE_ENABLE_Enabled << UART_ENABLE_ENABLE_Pos);
            NRF_UART0->TASKS_STARTRX = ;
            NRF_UART0->TASKS_STARTTX = ;
            break;
        }
    }
　　if(button_action == APP_BUTTON_RELEASE)
    {
        switch(pin_no)
        {
            case BUTTON_1:
            NRF_UART0->TASKS_STOPTX = ;
            NRF_UART0->TASKS_STOPRX = ;
            NRF_UART0->ENABLE       = (UART_ENABLE_ENABLE_Disabled << UART_ENABLE_ENABLE_Pos);
            break;
        }
    }
}

添加uart的相关函数

/**@brief   Function for handling app_uart events.
 *
 * @details This function will receive a single character from the app_uart module and append it to
 *          a string. The string will be be sent over BLE when the last character received was a
 *          'new line' i.e '\n' (hex 0x0D) or if the string has reached a length of
 *          @ref NUS_MAX_DATA_LENGTH.
 */
/**@snippet [Handling the data received over UART] */
void uart_event_handle(app_uart_evt_t * p_event)
{
    static uint8_t data_temp;
    uint32_t       err_code;

    switch (p_event->evt_type)
    {
        case APP_UART_DATA_READY:
            UNUSED_VARIABLE(app_uart_get(&data_temp));
            app_uart_put(data_temp);
            break;

        case APP_UART_COMMUNICATION_ERROR:
            APP_ERROR_HANDLER(p_event->data.error_communication);
            break;

        case APP_UART_FIFO_ERROR:
            APP_ERROR_HANDLER(p_event->data.error_code);
            break;

        default:
            break;
    }
}
/**@snippet [Handling the data received over UART] */

/**@brief  Function for initializing the UART module.
 */
/**@snippet [UART Initialization] */
static void uart_init(void)
{
    uint32_t                     err_code;
    const app_uart_comm_params_t comm_params =
    {
        RX_PIN_NUMBER,
        TX_PIN_NUMBER,
        RTS_PIN_NUMBER,
        CTS_PIN_NUMBER,
        APP_UART_FLOW_CONTROL_DISABLED,
        false,
        UART_BAUDRATE_BAUDRATE_Baud38400
    };

    APP_UART_FIFO_INIT( &comm_params,
                       UART_RX_BUF_SIZE,
                       UART_TX_BUF_SIZE,
                       uart_event_handle,
                       APP_IRQ_PRIORITY_LOW,
                       err_code);
    APP_ERROR_CHECK(err_code);
}
/**@snippet [UART Initialization] */