Is it suitable for delay in usart transmit ?

[Logiase]

https://github.com/nimaltd/atc/blob/3d673c5d9c24748bbfeb49c53c38c574c0a735fa/atc.c#L74

If the serial open with 115200 8N1, it will transmit a bit in

1/115200 = 0.000086805555555555555555555555555556 s

one frame take

11 * 1 / 115200 = 0.00095486111111111111111111 s

1 second is just enough.

But if we open the serial with higher baudrate, an one second delay may trigger a IDLE interrupt (if the receiver is a STM32).

And if we use RTOS, maybe some other high priority task will take the control and delay the transmit task.

Or maybe i am wrong (Im a still a noob in embedded development)

void atc_transmit(atc_t *atc, uint8_t *data, uint16_t len)
{
  for (uint16_t i = 0; i < len; i++)
  {
    while (!LL_USART_IsActiveFlag_TXE(atc->usart))
      ;
    LL_USART_TransmitData8(atc->usart, data[i]);
  }
  while (!LL_USART_IsActiveFlag_TC(atc->usart))
    ;
}

[nimaltd]

I dont underestand your problem :(

[Logiase]

Sorry for my bad English :(

I think it's wrong for putting such a huge delay in USART transmission, It's OK for lower baudrate. For example, if we use a higher baudrate and the AT device is a STM32 device (as modem, some self-made device), the AT device will trigger an IDLE interrupt.

What I mean is a 1s delay is too long for higher baudrate device, and if we use RTOS, USART transmission task may be suspend.

[nimaltd]

why do you want to use delay? atc_transmit does not need delay.

[Logiase]

why do you want to use delay? atc_transmit does not need delay.

I mean your code in atc.c line 69 to 79.

void atc_transmit(atc_t *atc, uint8_t *data, uint16_t len)
{
  for (uint16_t i = 0; i < len; i++)
  {
    while (!LL_USART_IsActiveFlag_TXE(atc->usart))
      atc_delay(1);                                                             ///< here
    LL_USART_TransmitData8(atc->usart, data[i]);
  }
  while (!LL_USART_IsActiveFlag_TC(atc->usart))
      atc_delay(1);                                                             ///< here
}

[nimaltd]

Oh. I see. I can not remember. But i had a problem with freertos and solved via delay.