STM32 - RS485 request-response - stm32

Question

I am trying to send request to measuring device and receive it's response using UART with interrupts. However communication is unstable, I am receiving incomplete or corrupted responses. I am not sure but I think it's because switching driver enable signal. Could you look at my code and give me some advice what am I doing wrong?
Here is my code:
int main(void){
HAL_Init();
SystemClock_Config();
MX_GPIO_Init();
MX_USART3_UART_Init();
HAL_GPIO_WritePin(GPIOB,GPIO_PIN_9,GPIO_PIN_SET); //RS 485 transmit mode
while (1)
{
if(HAL_UART_Transmit_IT(&huart3, (uint8_t*)aTxBuffer, 2) != HAL_OK)
{
while(1);
}
while (UartReady != SET);
UartReady = RESET;
if(HAL_UART_Receive_IT(&huart3, (uint8_t*)aRxBuffer, 4) != HAL_OK)
{
while(1);
}
while (UartReady != RESET);
//do somethink with received data
}
}
Here are my callback functions:
void HAL_UART_TxCpltCallback(UART_HandleTypeDef *UartHandle)
{
/* Set transmission flag: transfer complete */
HAL_GPIO_WritePin(GPIOB,GPIO_PIN_9,GPIO_PIN_RESET); //RS 485 receive mode
//DataRecieved = 0;
UartReady = SET;
}
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *UartHandle)
{
/* Set transmission flag: transfer complete */
HAL_GPIO_WritePin(GPIOB,GPIO_PIN_9,GPIO_PIN_SET); //RS 485 transmit mode
//DataRecieved = 1;
UartReady = SET;
}
Thank you very much

Answer 1

The data you transmit, does it also appear at your RX-buffer, while you expect it not to?

Answer 2

I am receiving incomplete or corrupted responses. I am not sure but I
think it's because switching driver enable signal. Could you look at
my code and give me some advice what am I doing wrong?
Not sure, but maybe it would help to toggle the DE pin not in the interrupt callback functions, and instead switch to "transmit mode" right before invoking HAL_UART_Transmit_IT() and then to switch back to receive mode after the transmission, or even after calling HAL_UART_Receive_IT(), to make sure it will catch the incoming bytes. Tiny delays do matter sometimes:
void set_transmit_mode(void)
{
HAL_GPIO_WritePin(GPIOB, GPIO_PIN_9, GPIO_PIN_SET); // RS 485 transmit mode
}
void set_receive_mode(void)
{
HAL_GPIO_WritePin(GPIOB, GPIO_PIN_9, GPIO_PIN_RESET); // RS 485 receive mode
}
{
//...
set_transmit_mode();
if (HAL_UART_Transmit_IT(&huart3, (uint8_t*)aTxBuffer, 2) != HAL_OK) {
// ...
}
while (UartReady != SET);
//set_receive_mode();
UartReady = RESET;
if (HAL_UART_Receive_IT(&huart3, (uint8_t*)aRxBuffer, 4) != HAL_OK) {
// ...
}
set_receive_mode();
while (UartReady != RESET);
//...
}