Information

If the selected priority is Rx FIFO first:
• if the Rx FIFO is a matched structure and is free-to-receive then the Rx FIFO is the
matching winner regardless of the scan for Mailboxes;
• otherwise (the Rx FIFO is not a matched structure or is not free-to-receive), then the
matching winner is searched among Mailboxes as described above.
If the selected priority is Mailboxes first:
• if a free-to-receive matched Mailbox is found, it is the matching winner regardless
the scan for Rx FIFO;
• if no matched Mailbox is found, then the matching winner is searched in the scan for
the Rx FIFO;
If both conditions above are not satisfied and a non free-to-receive matched Mailbox is
found then the matching winner determination is conditioned by the MCR[IRMQ] bit:
• if MCR[IRMQ] bit is negated the matching winner is the first matched Mailbox;
• if MCR[IRMQ] bit is asserted the matching winner is the Rx FIFO if it is a free-to-
receive matched structure, otherwise the matching winner is the last non free-to-
receive matched Mailbox.
See the following table for a summary of matching possibilities.
Table 42-117. Matching Possibilities and Resulting Reception Structures
RFEN IRMQ MRP Matched in MB Matched in
FIFO
Reception
Structure
Description
No FIFO, only MB, match is always MB first
0 0 X
1
None
2
-
3
None Frame lost by
no match
0 0 X Free
4
- FirstMB
0 1 X None - None Frame lost by
no match
0 1 X Free - FirstMb
0 1 X NotFree - LastMB Overrun
FIFO enabled, no match in FIFO is as if FIFO does not exist
1 0 X None None
5
None Frame lost by
no match
1 0 X Free None FirstMB
1 1 X None None None Frame lost by
no match
1 1 X Free None FirstMb
1 1 X NotFree None LastMB Overrun
Table continues on the next page...
Functional Description
K10 Sub-Family Reference Manual, Rev. 6, Nov 2011
1136 Freescale Semiconductor, Inc.