Stop Transmit interrupt manually during transmitting

[Olly Kao]

Hi

I'm doing a project to detect collision on UART, when I get data from Rx, I will compare it with the data I transmitted, if there aren't the same, means collision occurred, then I will immediately stop my transmitting interrupt to stop sources waste on the bus.

I am using

HAL_UART_Transmit_IT(&huart1, Message1.data, length);

to transmit data,​

I tried

UART_EndTransmit_IT(huart);

, but this function is not declared in main, so I directly write

CLEAR_BIT(huart1.Instance->CR1, USART_CR1_TCIE);
huart1.gState = HAL_UART_STATE_READY;

but the result is when I detected collision, the transmit yes stop, but then I recall HAL_UART_Transmit_IT(&huart1, Message1.data, length); transmit is not working, is there any more register I need to clear? or are there any other way to stop transmit interrupt during transmitting?

[Guenael Cadier · Accepted solution]

Dear @Olly Kao​ ,

Indeed, UART_EndTransmit_IT() is not expected to be called in Application code.

In order to abort transmit sequence, and to allow further calls to HAL_UART_Transmit_IT(), I would recommend use of dedicated HAL UART API, in blocking mode :

• HAL_UART_Abort() : aborts both TX and RX
• HAL_UART_AbortTransmit(() : aborts only TX

Similar primitives exist in non blocking mode, with execution of callbacks when Abort operations is completed ;

• HAL_UART_Abort_IT() : aborts both TX and RX, call HAL_UART_AbortCpltCallback() at the end
• HAL_UART_AbortTransmit_IT() : aborts only TX, call HAL_UART_AbortTransmitCpltCallback() at the end

Regards