USART frame detect IRQ. How?

[Haddock]

I'm modifying code for a Atmega AVR to a STM32L03 and encounter ISR(USART1_START_vect). It is a function that is called when the UART receives a start frame. I'm a newbie to this STM32-processor but I have googled and checked in inc-files but I cannot find any suitable code. I'm using HAL for now.

Have anyone a suggestion?

Thanx

[Tesla DeLorean]

What does your code do with such an interrupt?

If you want to detect the pin is active, perhaps use an EXTI interrupt​.

[waclawek.jan]

> when the UART receives a start frame

Define "start frame".

> I have googled and checked in inc-files

Read the Reference Manual (RM) to your STM32.

JW

[Haddock]

I have two UART ports. Both can occupy an interpreter and each port sets a flag that says "I now own the interpreter". That flag is set in this ISR().

I suppose a Frame detect IRQ coming when the hardware pin change state.

I must read about the EXTI interrupt..

[Haddock]

I suppose a Frame detect IRQ coming when the hardware pin change state in the beginning of the transfer.

[waclawek.jan]

If it's this

then as Clive said above, EXTI may be a direct equivalent. However, for the purpose you've described, IMO it's better to "flip the switch" upon reception of the first byte on given UART.

JW

[Haddock]

The note from 328PB is exactly what I want to happen in STM32-mcu.

The EXTI line 26 o 28 is activated in project.ioc file. I found the file stm320xx_hal_exti.c and what I can see this is the file that deals with EXTI.

Because I'm a newbie regarding this processor I searching for the interrupt function. Is it HAL_EXTI_IRQHandler() ?

If U have another Tips & Trix/manual for the processor and how to make a sw design in this target I would appreciate a tip. I found Target Device Docs and Resources in the Help menu i the IDE...

Thanx

[Piranha]

> I have two UART ports. Both can occupy an interpreter and each port sets a flag that says "I now own the interpreter". That flag is set in this ISR().

And why cannot it be done when the data is received?

[Haddock]

You are probably right. I can set the flag after the first byte has been received. The uart-ports has their own buffer but there is only one input buffer for the interpreter. I can set the flag in Rx-complete IRQ for the specific port.

Thanx. It is a simple solution and I get less IRQ:s.

[Amel NASRI · Accepted solution]

Hi @Håkan Nalén​ ,

If you need a simple EXTI example, you can refer to this wiki article: Getting started with EXTI.

Several ready to use examples are also available in the STM32CubeL0 package. You can refer to some of them here.

-Amel