Ensuring Data Consistency; Sequential Data Read - NEC UPD703116 User Manual

11.13 Ensuring Data Consistency

When the CPU reads data from CAN message buffers, it is essential for the read data to be consistent.
Two methods are used to ensure data consistency: sequential data read and burst read mode.

11.13.1 Sequential data read

When the CPU performs sequential access of a CAN message buffer, data is read from the buffer in the order
shown in Figure 11-50 below.
Only the FCAN internal operation can set the M_STATn register's DN bit (to 1) and only the CPU can clear it (to 0),
so during the read operation the CPU must be able to check whether or not any new data has been stored in the
message buffer.
Remark n = 00 to 31
CHAPTER 11 FCAN CONTROLLER
Figure 11-50. Sequential Data Read
Read CPU
Clear DN flag
clear DN = 1, set DN = 0
(SC_STATn)
Read data from
message buffer
DN = 0
(M_STATn)
Yes
End of CPU's read operation
User's Manual U14492EJ5V0UD
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