Rx Mask Registers (Rxgmask, Rx14Mask, Rx15Mask) - Freescale Semiconductor MCF5329 Reference Manual

23.3.4

Rx Mask Registers (RXGMASK, RX14MASK, RX15MASK)

These registers are used as acceptance masks for received frame IDs. Three masks are defined: a global
mask (RXGMASK) used for Rx buffers 0–13 and two separate masks for buffers 14 (RX14MASK) and
15 (RX15MASK). The meaning of each mask bit is the following:
MIn bit = 0: The corresponding incoming ID bit is don't care.
MIn bit = 1: The corresponding ID bit is checked against the incoming ID bit, to see if a match exists.
These masks are used for standard and extended ID formats. The value of the mask registers should not be
changed while in normal operation (only while in freeze mode), as locked frames that matched a message
buffer (MB) through a mask may be transferred into the MB (upon release) but may no longer match.
Table 23-5. Mask Examples for Normal/Extended Messages
MB2-ID
MB3-ID
MB4-ID
MB5-ID
MB14-ID
Rx_Global_Mask
1
Rx_Msg in
2
Rx_Msg in
3
Rx_Msg in
4
Rx_Msg in
5
Rx_Msg in
RX14MASK
6
Rx_Msg in
7
Rx_Msg in
1
Match for Extended Format (MB3).
2
Match for Normal Format. (MB2).
3
Mismatch for MB3 because of ID0.
4
Mismatch for MB2 because of ID28.
5
Mismatch for MB3 because of ID28, Match for MB14 (Uses RX14MASK).
6
Mismatch for MB14 because of ID27 (Uses RX14MASK).
7
Match for MB14 (Uses RX14MASK).
Freescale Semiconductor
Base ID
IDE
ID28.................ID18
1 1 1 1 1 1 1 1 0 0 0 0
1 1 1 1 1 1 1 1 0 0 0 1
0 0 0 0 0 0 1 1 1 1 1 0
0 0 0 0 0 0 1 1 1 0 1 1
1 1 1 1 1 1 1 1 0 0 0 1
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 1 0 0 1 0
1 1 1 1 1 1 1 1 0 0 1 1
0 1 1 1 1 1 1 1 0 0 0 0
0 1 1 1 1 1 1 1 0 0 0 1
0 1 1 1 1 1 1 1 1 1 1
1 0 1 1 1 1 1 1 0 0 0 1
0 1 1 1 1 1 1 1 0 0 0 1
MCF5329 Reference Manual, Rev 3
Extended ID
ID17......................................ID0
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 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
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
1 1 1 1 1 1 1 0 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 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1
FlexCAN
Match
1
MB3
2
MB2
3
4
5
MB14
6
7
MB14
23-11