Hello,
I'm here on H75x. I'm looking for portable way to do a timeout check via timer.
Here, I want a timeout IRQ if UART receive DMA hangs up.
First I setup a OnePulse timer in Cube. It generates the following code:
if (HAL_TIM_Base_Init(&htim6) != HAL_OK)
{
Error_Handler();
}
if (HAL_TIM_OnePulse_Init(&htim6, TIM_OPMODE_SINGLE) != HAL_OK)
{
Error_Handler();
}The second init function does almost the same as the first but activates the OneShot mode which stops the counter immediately if IRQ is fired.
I was looking for a suitable HAL function to setup the timeout value but failed. Instead I use
__HAL_TIM_SetCounter(htim, 1); // set start value
__HAL_TIM_SetAutoreload(htim, ulDelay); // set end value
__HAL_TIM_ENABLE(htim);The last macro is required because after the RX DMA is done in time, the timer has to be stopped to prevent from false timeout IRQs.
Is this the way to go? Is there a HAL-compatible solution which I didn't get?
Thanks
@TDK wrote:
If the sender doesn't respond, the DMA doesn't do anything since no data shows up and the line remains idle. It would not block since there is nothing for it to do. You would not be notified at all in this case and would need some other timer mechanism.
This is what I expected. This would cause that my statemachine is endless waiting for data. I want to notify the upper SW layer that the "read data from UART" request failed. The higher layer may retry and abort after certain retries.
Therefore I need kind of timeout check mechanism. I checked the reference manual for h75x family and found this note here:
48.5.16 USART receiver timeout
The receiver timeout feature is enabled by setting the RTOEN bit in the USART_CR2
control register.
The timeout duration is programmed using the RTO bitfields in the USART_RTOR register.
The receiver timeout counter starts counting:
• from the end of the stop bit if STOP = ‘00’ or STOP = ‘11’
• from the end of the second stop bit if STOP = ‘10’.
• from the beginning of the stop bit if STOP = ‘01’.
When the timeout duration has elapsed, the RTOF flag in the USART_ISR register is set. A
timeout is generated if RTOIE bit in USART_CR1 register is set.I stepped thru the code of HAL_UARTEx_ReceiveToIdle_DMA:
It seems that CR2.RTOEN and RTOR.RTO are not configured. Nevertheless, I get an DMA done event via HAL_UARTEx_RxEventCallback after data received.
I found a HAL function HAL_UART_EnableReceiverTimeout(). It seems that it is used to specify an idle time, but I'm unsure if this does affect the same idle time used by HAL_UARTEx_ReceiveToIdle_DMA.
Have I mixed up two different things, Idle Time and Receive Timeout?
