NXP Semiconductors MWCT101 S Series, Справочное руководство

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3. no_cmp: The Rx SMB contents are not compared with the MB contents.
4. cmp_msk: Compares the Rx SMB contents with MB contents taking into account the masks.
5. SMB[IDE] and SMB[RTR] are not taken into account when IDAM is type C.
A reception structure is free-to-receive when any of the following conditions is satisfied:
• The CODE field of the mailbox is EMPTY.
• The CODE field of the mailbox is either FULL or OVERRUN and it has already
been serviced (the C/S word was read by the CPU and unlocked as described in
Mailbox lock mechanism ).
• The CODE field of the mailbox is either FULL or OVERRUN and an inactivation
(see Mailbox inactivation ) is performed.
• The Rx FIFO is not full.
The scan order for mailboxes and Rx FIFO is from the matching element with lowest
number to the higher ones.
The matching winner search for mailboxes is affected by MCR[IRMQ]. If it is negated,
the matching winner is the first matched mailbox regardless if it is free-to-receive or not.
If it is asserted, the matching winner is selected according to the priority below:
1. the first free-to-receive matched mailbox;
2. the last non free-to-receive matched mailbox.
It is possible to select the priority of scan between mailboxes and Rx FIFO with
CTRL2[MRP].
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 of
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 MCR[IRMQ]:
• If MCR[IRMQ] is negated, the matching winner is the first matched mailbox.
• If MCR[IRMQ] 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.
Functional description
MWCT101xS Series Reference Manual, Rev. 3, 07/2019
1666 NXP Semiconductors