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Chapter 13
FCAN Interface Function
Preliminary User’s Manual U14913EE1V0UM00
13.4.3 Ensuring data consistency
If the CPU reads data from the CAN message buffers, the consistency of data read has to be ensured.
Therefore two mechanisms are provided:
• Sequential data read
• Burst mode data read
(1)
Sequential data read
If the data is read by the CPU by sequential accesses to the CAN message buffers, the following
sequence has to be observed:
Figure 13-44: Sequential CAN Data Read by CPU
As the DN flag
is only set by the CAN module and cleared by the CPU only, it is ensured that the
CPU can recognize that new data is stored in the message buffer during the read operation.
Remark:
If the CPU reads the data by only one read access, the data consistency is always ensured.
Therefore the check of the DN flag after reading the data is not necessary.
CPU READ
Clear DN
Read data
DN
set?
END
Yes
No
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