Canbus Filtering with the MCP_CAN_lib-master library

Using Arduino Programming Questions
1

Hi,
Like many people i have been trying to get my head around this, and looked at the hundred or so explanations already posted.
I thought i had it figured out, but it seems any message gets through.

My code for testing is quite simple. I just want 2 message ID's to be allowed through, the data is unimportant.

canbusspeed =3 ;
RXid = 0x761

then main code :-

switch (canbusspeed) {
    case 1:
      CAN0.begin(MCP_STDEXT, CAN_250KBPS, MCP_16MHZ);
      break ;
    case 2:
      CAN0.begin(MCP_STDEXT, CAN_500KBPS, MCP_16MHZ);
      break;
    case 3:
      CAN0.begin(MCP_STDEXT, CAN_1000KBPS, MCP_16MHZ);
      break; }
  CAN0.setMode(MCP_NORMAL);                      
  CAN0.init_Mask( 0, 0, RXid | RXid+1 );       // Init first mask...
  CAN0.init_Filt( 0, 0, RXid );                // Init first filter...
  CAN0.init_Filt( 1, 0, RXid+1 );               // Init second filter...

I bitwise-or my TXid and its Following ID( +1) to create my mask, so 0x761 and 0x762 as these are the two addresses I would like allowed through.
I then create my first and second filter. However, when testing, any message ID gets through.

Thanks for any pointers on this.

2

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