Content:
Hi,
I am using UART on STM32G4 in interrupt mode (RXNEIE + NVIC enabled).
I observed the following situation:
1. A byte is received → RXNE = 1
2. At that moment, UART interrupt is disabled (critical section)
3. Later I re-enable the UART interrupt
4. But the RXNE interrupt does NOT fire, even though RXNE is still = 1
This causes my Modbus task to freeze because no further RXNE interrupts are generated.
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My question:
Is this the expected behavior?
i.e.,
Does STM32G4 USART generate the RXNE interrupt only when RXNE transitions from 0 to 1,
and not when RXNE is already 1 at the moment the interrupt is enabled?
I could not find a clear statement about this behavior in the Reference Manual.
If this is the intended design, please confirm, and if possible, point to the exact section in the documentation.
Thank you.
