Motorola MPC533 Reference Manual page 694

TouCAN Architecture
The value of the mask registers should not be changed during normal operation. If the mask
register data is changed after the masked identifier of a received message is matched to a
locked message buffer, that message will be transferred into that message buffer once it is
unlocked, regardless of whether that message's masked identifier still matches the receive
buffer identifier. Table 16-6 shows mask bit values.
Mask Bit
Table 16-7 shows mask examples for normal and extended messages. Refer to
Section 16.7, "Programmer's Model" for more information on Rx mask registers.
Table 16-7. Mask Examples for Normal/Extended Messages
Message Buffer (MB)/Mask
MB2
MB3
MB4
MB5
MB14
Rx Global Mask
Rx Message In
Rx 14 Mask
Rx Message In
1
Match for extended format (MB3).
2
Match for standard format (MB2).
3
No match for MB3 because of ID0.
4
No match for MB2 because of ID28.
5
No match for MB3 because of ID28, match for MB14.
6
No match for MB14 because of ID27.
7
Match for MB14.
16-8
PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE
Table 16-6. Receive Mask Register Bit Values
0 The corresponding incoming ID bit is "don't care"
1 The corresponding ID bit is checked against the incoming ID
bit to see if a match exists
Base ID
ID[28:18]
1 1 1 1 1 1 1 1 0 0 0
1 1 1 1 1 1 1 1 0 0 0
0 0 0 0 0 0 1 1 1 1 1
0 0 0 0 0 0 1 1 1 0 1
1 1 1 1 1 1 1 1 0 0 0
1 1 1 1 1 1 1 1 1 1 0
1 1 1 1 1 1 1 1 0 0 1
1 1 1 1 1 1 1 1 0 0 1
1 1 1 1 1 1 1 1 0 0 1
0 1 1 1 1 1 1 1 0 0 0
0 1 1 1 1 1 1 1 0 0 0
0 1 1 1 1 1 1 1 1 1 1
1 0 1 1 1 1 1 1 0 0 0
0 1 1 1 1 1 1 1 0 0 0
MPC533 Reference Manual
Values
Extended ID
IDE
ID[17:0]
0 —
1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1
0 —
1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1
1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1
1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 1
1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1
0 —
1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 0
0 —
1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1
1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0
1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1
1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1
Match
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—
—
—
—
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1
3
2
2
3
—
4
—
5
—
—
6
—
7
14
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