MCP2515 in Interrupt mode using STM32WL

[FPicc.1]

Hi all,

I'm using MCP2515 for a CAN application in the NUCLEO STM32WL board. I've managed to get it to work in pulling mode, however, I want to use interrupt mode. 

For what I looked, I just have to enable the MCP interrupt pin in EXTI mode in cubeMX, but the MCP interrupt pin that I set (PA0) is already set as the BUT1 pin (on board button). I didn't change the configurations, only set in the callback to activate if occurs the rising edge of BUT1_Pin (tried with falling edge too).

It didn't work, but I don't know if I have to configure something more, or the fact that the pin is shared with the button changes something and it could be the problem.

Any insights will be helpfull.

[Tesla DeLorean]

And how is the Button wired? Pull-up to VCC, button pressed to GND ?

Not sure the MCP2515 uses an open-collector output, or can be configured from a driver, level or pulse sense. Sure the Data Sheet would elucidate.

Use EXTI0

Use a scope and confirm behaviour and expectations

[FPicc.1]

Here's the schematic of BUT1 pin. I'm not sure if the PA0 bypasses this connection, or if would only work if the button is pressed

 

[Tesla DeLorean]

Ok, so NUCLEO-WL55JC(1) board

You could remove the solder-bridge (SB16) or link, or move to PC13 (SB15) if nothing else conflicts, and use the EXTI15_9

That would free PA0 for your own, personal use, on the MORPHO connection/headers

[Techn]

Ad per datasheet the int pin can be configured for different purposes.  Are you using any breakout,  then check the jumpers.  I  guess it needs pullups 

[FPicc.1]

Also don't know, here's the schematic on the board (consider PA0 as PB14 (CAN_INT_Pin))

 

[Techn]

So either enable pullups for the stm32 pin or connect pullups.  Datasheet is your best friend for the register programming.  Good luck