Using the MIL-STD-1760 option (FX1553-4, FM1553-4, FMX-M1553-4, MAX-IP-2162-AEK, MAX-IP-2162-2AEK, MAX-IP-2166-AEK and MAX-IP-2166-2AEK), the BC and RT can send a checksum word in place of the last data word of a specific message. The BM, BC, and RTs can verify the checksum received.

Checksum Verification

To enable the checksum verification, call the mxfMIL1553MsgChecksumEnableSet() function with the channel handle of the BM. This will enable the checksum verification on the BM for this specific RT address/subaddress/direction. It will also enable the checksum verification on the BC for the same RT address/subaddress and on the subaddress of the specified RT as well. The address/subaddress/type should be the one of the BC command for BC-RT and RT-BC transactions and the one from the second command (RTtx) for RT-RT transactions. Note that the BM monitor mode must be set to either string or message mode for the checksum verification to work.

Checksum Generation

To enable the checksum generation on a RT, call the mxfMIL1553MsgChecksumEnableSet() function with the channel handle of the RT for any TX subaddress. To enable the checksum generation on a BC, use the MXF_MIL1553_TXPERIODIC_MJRFRAME_MSG_OPT_CHECKSUM_ENABLE option of the MXF_MIL1553_TXPERIODIC_MJRFRAME_MSG.options field for major frame message or use the MXF_MIL1553_TXAPERIODIC_REC_CTRL_CHECKSUM_ENABLE control bit of MXF_MIL1553_DATAREC.control for aperiodic message.