USART_WakeUpFromStop1 leads to lost characters

[BErik.1]

While experimenting[*] with the USART_WakeUpFromStop1 example on my NUCLEO-L496ZG I noticed that repeatedly entering STOP1 mode leads to dropped character if running with a baudrate > 4800 bps. I'm using STOP1 mode in a different project and I hoped to find a way to correctly communicating on 115200.

Any pointers on how to achieve this?

[*] I had to some minor modifications to STs example

* Rewrote the reception callback to store the received bytes in an array and printout in main() instead of echoing them in the handler

void USART_CharReception_Callback(void)
{
  /* Read Received character. RXNE flag is cleared by reading of RDR register */
  ubReceivedChar = LL_USART_ReceiveData8(USART1);
  rx_buff[rx_buff_i++] = ubReceivedChar;

  /* Check if received value is corresponding to specific one : S or s */
  if ((ubReceivedChar == 'S') || (ubReceivedChar == 's'))
  {
    ...

* Removed everything not related to STOP mode from the main loop

while (ubFinalCharReceived == 0)
{
  PrepareUSARTToStopMode();
  EnterStop1Mode();
}