Possibility for UART receive data loss?

Question

In a lot of examples using STM32, HAL, where UART data is received by interrupt the code looks like:

Initially (to start the receiving):

HAL_UART_Receive_IT(&huart1, Rx_data, 1);            

When an interrupt receive is complete:

//Interrupt callback routine
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)  
{
    ...
    HAL_UART_Receive_IT(&huart, Rx_data, 1);            
}

I am wondering, is there a possibility that bytes are lost between the actual receiving and after the (receive complete) callback where the interrupt is started again.

Or is it assumed the interrupt handler above is so short the data will still be in the UART buffer?

Answer 1

H/W flow control between UART's RTS/CTS with 16 byte Rx buffers are intended to prevent overflow. But it useful to include parity to improve signal integrity in case flow control latency is too long.

When demanding low error rates with software retry or data filtering or testing max data rates in noisy environments, it is useful to enable parity.

It is also beneficial to check for ; stop bit errors, buffer overflow errors and test with simulated environmental noise. (ESD, RF pulses , SMPS CM noise etc. lack of earth grounds etc. )

Answer 2

The interrupt driven UART communication is probably about 50 - 60 lines of the code using the registers. HAL is a huge black hole - who knows what is inside?

For MIDI you do not have too much option but in general it is good to have some kind of the protocol with the CRC at the end of every packet (many STM micros have the CRC hardware built in).