MSM9225B User’s Manual
Chapter 3 Operational Description
3 – 4
3.1.4 Message Box Rewrites during Operation
The procedure to rewrite the Identifier (ID) and Data Length Code (DLC) during operation, excluding the
time that initial settings are made for the message boxes, is indicated below. The number of message boxes
set in the NMES register at the initial setting is the number of (valid) message boxes that can be rewritten.
Start rewrite
Set MMA bit of message
control register (x0hex) to 1
Read MMA bit
MMA = 1?
Rewrite
FRM, DLC3-DLC0, ID28-ID0
Set MMA bit of message
control register to 0
Rewrite complete
YES
NO
All message box
settings complete?
YES
NO
Since the MMA bit cannot be set to 1 while
message boxes are being accessed from
the CAN side, read and verify its value.
Since the MMA bit cannot be set to 0 while
message boxes are being accessed from
the CAN side, read and verify its value.
Read MMA bit
MMA = 0?
YES
NO
Figure 3-4 Message Box Rewrite Flowchart
Summary of Contents for MSM9225B
Page 7: ...Chapter 1 Overview...
Page 13: ...Chapter 2 Register Descriptions...
Page 53: ...Chapter 3 Operational Description...
Page 62: ...Chapter 4 Microcontroller Interface...
Page 71: ...Chapter 5 Electrical Characteristics...
Page 81: ...Appendixes...