ST72561J9-Auto STMicroelectronics, ST72561J9-Auto Datasheet - Page 227

• Manufacturer Part Number: ST72561J9-Auto
• Description: 8-bit MCU for automotive
• Manufacturer: STMicroelectronics

Specifications of ST72561J9-Auto

• Hdflash Endurance: 100 cycles, data retention 20 years at 55 °C
• 5 Power Saving Modes: halt, auto wake up from halt, active halt, wait and slow

ST72561-Auto
17.4.4
Figure 103. Filtering mechanism - example
The example above shows the filtering principle of the beCAN. On reception of a message,
the identifier is compared first with the filters configured in identifier list mode. If there is a
match, the message is stored in the FIFO and the index of the matching filter is stored in the
filter match index. As shown in the example, the identifier 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 identifiers configured in the filters, the message is
discarded by hardware without software intervention.
Message storage
The interface between the software and the hardware for the CAN messages is
implemented by means of mailboxes. A mailbox contains all information related to a
message; identifier, data, control and status information.
Transmit mailbox
The software sets up the message to be transmitted in an empty transmit mailbox. The
status of the transmission is indicated by hardware in the MCSR register.
Message Discarded
Identifier
Identifier
Mask
Identifier
Identifier
Identifier
Identifier
Mask
No Match
Found
Identifier
n+m
n+1
Doc ID 12370 Rev 8
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
Data
Receive FIFO
Message
Stored
beCAN controller (beCAN)
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