ST92F124 datasheet(336/429 Pages) STMICROELECTRONICS

Part #	ST92F124

Description	8/16-BIT SINGLE VOLTAGE FLASH MCU FAMILY WITH RAM, E3 TM(EMULATED EEPROM), CAN 2.0B AND J1850 BLPD

PDF	429 Pages

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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CONTROLLER AREA NETWORK (bxCAN)

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.

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.

Message Discarded

Identifier

n+1

Mask

Identifier

n+m

Mask

Identifier

Message Received

Ctrl

Data

Identifier #2 Match

Message

Stored

Receive FIFO

No Match

Found

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

ST92F124 Datasheet(PDF) 336 Page - STMicroelectronics