UART data receive acknowledgement

[Nico3]

Two devices A & B are communicating on UART. A sends data stream to B. B sends one byte data back to A to acknowldge that data has been received. 

I want to implement if A doesn't receive acknowledgement from B then it display Error message on LCD.

Please suggest best logic in A to implement this.

As far I think I should start the UART_Receive_IT API for one byte . and complete callback sets the flag for acknowlegement. Incase flag is not set within one second or so after sending data then A display Error message on LCD. Should I start HAL_Delay(1000) after sending data and then check for flag set or not?

If anyother best way, kindly suggest. 

I am still relatively new to coding word..so trying to find best ways.. ;)

[Tesla DeLorean]

>>Should I start HAL_Delay(1000) after sending data and then check for flag set or not?

No, you'd do better taking a TickCount, say HAL_GetTick(), and use that to determine if enough time has expired without getting a callback with the acknowledgment byte 

If it responds more quickly you can proceed to do other things.

[Andrew Neil · Accepted solution]

The blocking HAL_UART_Receive() API takes a timeout:

the non-blocking HAL_UART_Receive_IT() doesn't:

Using HAL_Delay() effectively makes your code blocking - so there seems no point in using the non-blocking API?

[Nico3]

Cool,

So after sending data , i run the blocking HAL_UART_Receive()with timeout of say 1 second and then check the HAL_StatusTypeDef return. 

[Andrew Neil]

Yes.

And, of course, check the received character (if any) - to make sure it's the correct acknowledgement.