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13
CAN MODULE
13-123
32185/32186 Group Hardware Manual
Rev.1.10 REJ09B0235-0110 May 15, 07
13.5 Transmitting Data Frames
(4) Completion of data frame transmission
When data frame transmission has finished, the CAN Message Slot Control Register’s TRFIN (Transmit/
Receive Finished) bit and the CAN Slot Interrupt Request Status Register are set to "1." Also, a timestamp
count value at which transmission has finished is written to the CAN Message Slot Timestamp
(C0MSLnTSP, C1MSLnTSP), and the transmit operation is thereby completed.
If the CAN slot interrupt request has been enabled, an interrupt request is generated at completion of
transmit operation. The slot which has had transmission completed goes to an inactive state and remains
inactive (neither transmit nor receive) until it is newly set in software.
B'1000 0010
B'0000 0001
(Note 1)
B'1000 0001
B'0000 0000
(Note 1)
B'1000 0000
Write H'80
Transmission aborted
Transmit request
accepted
Note 1: When in this state, data can be written to the message slot.
Transmission
aborted
Transmit
request
accepted
Transmission
aborted
Transmission completed
Transmission
aborted
Transmission
completed
Wait for transmission
B'0000 0010
Lost in CAN bus arbitration
or a CAN bus error occurs
Lost
in
CAN
bus
arbitration
or
a CAN
bus
e
rror
o
ccurs
1
2
3
4
5
6
b7 (b15)
(b8)
b0
RM
RR
TR
RL
RA
ML
TRSTAT TRFIN
00000000
CAN message slot control register bit allocation
Figure 13.5.2 Operation of CAN Message Slot Control Register during Data Frame Transmission
13.5.3 Transmit Abort Function
The transmit abort function is used to cancel a transmit request that has once been set. This is accomplished
by writing H’0F to the CAN Message Slot Control Register for the slot to be canceled. When transmit abort is
accepted, the CAN module clears the CAN Message Slot Control Register’s TRSTAT (Transmit/Receive Sta-
tus) bit to "0," allowing for data to be written to the message slot. The following shows the conditions under
which transmit abort is accepted.
[Conditions]
When the target message is waiting for transmission
When a CAN bus error occurs during transmission
When lost in CAN bus arbitration