38.7.1 Filter Configuration
The filters are controlled by the CxFLTCONy registers. The filters must be disabled by clearing the FLTEN bit before changing the filter or mask object; the module need not be in Configuration mode. After the filter object is updated, the Buffer Pointer, FnBP, has to be initialized and the filter can be enabled by setting the FLTEN bit. The FnBP points to the FIFO where the matching receive message needs to be stored.