st92f124 STMicroelectronics, st92f124 Datasheet - Page 335

• Manufacturer Part Number: st92f124
• Description: 8/16-bit Single Voltage Flash Mcu Family With Ram, E3 Tmemulated Eeprom, Can 2.0b And J1850 Blpd
• Manufacturer: STMicroelectronics

CONTROLLER AREA NETWORK (Cont’d)
Figure 150. Filtering Mechanism - example
The example above shows the filtering principle of
the bxCAN. On reception of a message, the iden-
tifier is compared first with the filters configured in
identifier list mode. If there is a match, the mes-
sage is stored in the associated FIFO and the in-
dex of the matching filter is stored in the Filter
Match Index. As shown in the example, the identi-
fier matches with Identifier #2 thus the message
content and MFMI 2 is stored in the FIFO.
Message Discarded
Identifier
Identifier
Mask
Identifier
Mask
Identifier
Identifier
Identifier
No Match
Found
Identifier
n+m
n+1
n
0
1
2
Ctrl
Identifier #2 Match
Message Received
n: number of single identifiers to receive
m: number of identifier groups to receive
n and m values depend on the configuration of the filters
CONTROLLER AREA NETWORK (bxCAN)
If there is no match, the incoming identifier is then
compared with the filters configured in mask
mode.
If the identifier does not match any of the identifi-
ers configured in the filters, the message is dis-
carded by hardware without disturbing the soft-
ware.
Data
Receive FIFO
Message
Stored
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