How to detect MODBUS RTU end of frame( silent interval) using uart interrupts?

[parth kothiya]

MODBUS RTU frame start and end with >=3.5 char interval i want to detect this interval using stm32 uart interrupt after detection of frame and i can process data further.

How can i detect this silent char interval using uart interrupt or any other way to do this?

[Ozone]

Some STM32 MCUs have UART peripherals with integrated idle timer. You could use that.

Or for MCUs without, start/restart a 3.5-character timer at each character reception. If it times out, it's probably a frame end.