app_uart_put() fails after softdevice initialization

[diocorreia]

The communication between the UART peripheral and the nrf52840 works fine until some device connects to the nrf device via BLE. Using a digital logic analyzer I'm able to identify that the nrf52840 only puts the first character of the string in the UART bus.

My setup:

• nrf52840
• esp8266
• nRF52 SDK v16.0.0
• SoftDevice S140

UART's tx function:

void esp8266_tx(char *str){
    uint8_t i = 0;
    uint8_t err_code;
    while(str[i] != '\0'){
        while(app_uart_put(str[i++]) != NRF_SUCCESS);
    }
    err_code = app_uart_put(0xD);  //CR
    if(err_code != NRF_SUCCESS){
            NRF_LOG_INFO("error @ esp8266_sendAT: %d", err_code);
            NRF_LOG_FLUSH();
    };
    err_code = app_uart_put(0xA); //LF
    if(err_code != NRF_SUCCESS){
            NRF_LOG_INFO("error @ esp8266_sendAT: %d", err_code);
            NRF_LOG_FLUSH();
    };
    nrf_delay_ms(300);
    app_uart_flush();
}

[Jared]

Hi,

The uart operation is properly interrupted by the Softdevice. What happens after the device has connected? Does your application return to the uart operation? You can try to pause the program with the debugger and see where it is after a connection event. You should check if the program is in the error handler.

regards

Jared

[diocorreia]

You're right the function was being interrupted, during the first while(), by the Softdevice. I solved the problem by using recursion instead.

Thx!