Countermeasures for shortening STOP bit in UART transmission processing

[Hiro]

Hello Nordic Support!

The stop bit of the last character is short in the Uart output part, and the other MPUy cannot receive the character.
How do I fix it until I send the STOP bit completely?

The waveform and the transmission program are described below.

void aUartInterface_SendData(uint8_t *data, uint16_t len)
{
    uint32_t timeout;
    uint32_t start_tick;
    uint32_t current_tick;
    uint8_t sleep = 0;
   
    if(len == 0)
        return;
   
    timeout = TIMEOUT_TICKS*len;
    start_tick = cnt_get();
   
    // check sleep or not
    if(mUartProcessing == 0)
    {
        uart_wakeup();
        sleep = 1;
    }
   
    NRF_GPIO->OUTSET = ((uint32_t)1 << PIN_UART_SENDING);
   
    NRF_UART0->TASKS_STARTTX = 1;
    for(uint16_t i=0; i<len; i++)
    {
        NRF_UART0->TXD = data[i];
        while(NRF_UART0->EVENTS_TXDRDY==0)
        {
            //
            current_tick = cnt_get();
            if( cnt_diff_compute(current_tick, start_tick) > timeout)
            {
                NRF_UART0->EVENTS_TXDRDY = 0;
                NRF_UART0->TASKS_STOPTX = 1;
                NRF_GPIO->OUTCLR = ((uint32_t)1 << PIN_UART_SENDING);
                return;
            }
        }
        NRF_UART0->EVENTS_TXDRDY = 0;
    }
    NRF_UART0->TASKS_STOPTX = 1;
   
    NRF_GPIO->OUTCLR = ((uint32_t)1 << PIN_UART_SENDING);
   
    if(sleep)
        uart_sleep();
}

let me know.

Best Regards

Hirotoshi NAGAO

CHINO Corporation

[Turbo J]

Try waiting for EVENTS_STOPPED after staring the stop task with TASKS_STOPTX;

[Hiro]

Thanks for your comments.

I use MDK ARM.
I tried to code EVENTS_TXSTOPPED, but it doesn't seem to be a member of NRF-UART0.

Compilation fails.
For sending relationships, only EVENTS_TXRDY is a member.
Is this a substitute?

[Turbo J]

My mistake - this event is only available in UARTE peripherials.

Did you configure the TX pin as "output high", i.e. set the corresponding bit to 1 in the GPIO output register?

[Hiro]

Yes, of course.There is no problem with the function of UARTE peripherials
Event_txstop cannot be used in MDK ARM register definition.