38.7.2.2 Mask Bits

The mask object is used to ignore selected bits of the received identifier. The masked bits (mask bits with a value of ‘0’) of the RXMAB will not be compared with the bits in the filter object. For example, to receive all messages with Identifiers 0, 1, 2 and 3, it is required to mask the lower two bits of the identifier by clearing the corresponding bits of the mask object.