Oki MSM9225B, User Manual

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MSM9225B User’s Manual
Chapter 2 Register Descriptions
2 – 17
2.4.1 CAN Control Register (CANC: 0Ehex)
This register controls the operation of CAN.
The bit configuration is as follows:
MSB Not
used
RxF TxF CANA SYNC
Not
used
TIRS INIT
LSB CANC (0Ehex), *R/W: R/W
Initial
value:
0 0 0 0 0 0 0 1
0 Release initialization mode
1 Set initialization mode
0 Terminate search of transmission
message boxes
1 Search transmission message boxes
Unused bit
Write a “0”.
0 Synchronize at the falling edge
1
Synchronize at both the rising and
falling edges
0 No writing is being done to the message
boxes
1 Now writing receive data to the
message boxes
0 Transmission operation halted
1 Transmission operation is in progress
0 Receive operation halted
1 Receive operation is in progress
Unused bit
Write a “0”.
* TIRS is in the read-only state when “0”, and CANA, TxF, RxF are read-only bits.
Figure 2-18 CAN Control Register (CANC)
(1) Initialization bit: INIT
This is the bit for setting the initialization mode of the communication control section.
At the time of initialization, start the initialization after writing a “1” to INIT and reading it to ensure
that INIT has been set to “1”. Also, at the end of initialization, write a “0” to INIT, then read this bit to
make sure that it has been set to “0”. In either case, make sure to carry out the above operations
because neither “1” nor “0” will be set immediately. Note that data cannot be written to the INIT bit
while the CAN bus is at the dominant level.
If INIT is set to “1” during transmission or reception, the initialization is started after completing the
communication. Although the communication operation stops when INIT is set to “1”, the contents of
the message memory and the control registers will be retained, except the content of the MMA bit of the
message control register within the message box.
To initialize the message memory, first write the number of message boxes to be used in the message
box count setting register NMES, and then write the message control register, identifier 1, and identifier
2 in sequence from the message box number 0 for all the message boxes to be used.
At reset, INIT is set to “1”.