To implement the various types of bridges and the resultant end stations discussed in the
ANSI and IEEE standards, the MAC can be used as follows:
1. TR_BR_FWD , for a transparent bridge, and MATCH , for an end station, provide a
MAC status setting functionality.
2. Promiscuous mode provides a MAC status repeating functionality.
3. A MAC status clearing functionality is provided by Option_2 for an end station.
4. Both MATCH and TR_BR_FWD provide the necessary timing extensions required
to perform source address routing and transparent bridging table lookup when
EXT_DA_MATCH = 1.
5. RABORT or RABORT2 can be used with the MATCH or TR_BR_FWD pin, or in
promiscuous mode, to stop the transfer of a frame from the MAC to the FSI and to
properly set the C-bit for a rejected or incompletely received frame.
MC68838 USER'S MANUAL