Hello! I want to use the message object 15 as a general receive object. Message 1 .. 14 are used for transmit objects. I used 0x000 as mask for the message 15 and didn't fill the arbitration register. (I use a Siemens/Infineon C167CR processor.) When a message is received an interrupt is generated, but I fail getting the message ID out of the arbitration field. I tried the following code: dummy_int1=UAR_MO15; RCV_ID=(unsigned long) (((dummy_int1<<8)+(dummy_int1>>8))>>5); But I always get "0" as result ... Any ideas where the problem is? Is it necessary to fill the arbitration register even if i want to receive multiple IDs? Unfortunately the CAN chapter at the User's Manual for the C167CR didnt't help me! Thanks in advance! SVEN