CAN Rx Interrupt not triggering in Normal mode (worked in Loopback mode)

[Aswin]

Hi

I am trying to communicate CAN. I am using two boards Nucleo-G474RE and Nucleo-H755ZI-Q and two MCP2551 as transceiver.
On either side, program works for External loop back configuration. ( I did step by step debug to ensure the transmitting data is getting received or not).

But I am not getting the interrupt when in normal mode. I also tried using a single board with shorting tx and rx of the transceiver and also using two boards.
What might be the issue?

I have only attached the IOC file and main.c file for Nucleo-H755ZI-Q and it is similar for Nucleo-G474RE also.

[Aswin]

Hi Sorry for the delayed response.

I tried with configuring two different CAN in a single board. Still there is no progress. I have attached the cube project files.
I used Nucleo-H755ZI-Q. 
I have some confusion regarding the TX,RX pins of the FDCAN in the MCU. 

[Karl Yamashita]

You only show TX/RX connected to the MCP2551.

Is the MCP2551 VDD connected to 5V and VSS connected to ground? Is the Rs pin connected to ground as well?

[Aswin]

Yes, since MCP2551 powering connections are obvious I didn't mention in the connection drawing.
VCC is connected to 5V and GND pins are shorted along with the board GND.
You did mention about Rs pin:  There is no Rs pin ; is it a typo for 'Rx' - if yes then I didnt connect it to the ground

[Karl Yamashita]

The MCP2551 does indeed have an Rs pin. You didn't mention that you are using a custom PCB board with the MCP2551 on it. If you look at the schematic for that PCB board, the Rs pin is grounded. 

The next step is to get a oscilloscope to see if you are getting CAN bus messages transmitted. Then you can determine if it's an Rx or Tx issue.

[Aswin]

OK. Let me try using oscilloscope.
Can you please confirm whether I am using the right pin or not?
In  the manual, I can only find 2 pins for CAN. Initially i used it for FDCAN1 and later on I was confused which pin i will be using for FDCAN2.
Then when i configured it, by default it was gave me PB12 and PB11 pins. I did try with that. Then I searched in the CUBE IDE itself for alternative pins (Ctrl + hold mouse - alternative pin configuration will blink in the pinout). It showed me PB5 and PB6. I did try with that but it didnt help.

[SofLit]

1- In the manual gives you an example of CAN pin usage (PD0 and PPD1) and it's not a restriction:

To find the CAN pin usage possibilities the datasheet is the right document to refer to:

Many possibilities for FDCAN1 and FDCAN2 offer to you (make a search in the document). But you need to select a pin not used in the board i.e. it's a free pin and not connected to nothing else in the schematics.

2- And this transceiver pin needs to be pulled to the ground:

I see from your screen shot you are using shields but better to double check with a multimeter (in continuity mode with transceivers are powered off).