
CHAPTER 19 CAN CONTROLLER
Preliminary User’s Manual U16541EJ1V0UM
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TSTAT
CAN Transmission Status Bit
0
No transmission activity on the CAN bus
1
Transmission activity on the CAN bus
Remark
The TSTAT bit is set (1) under the following conditions.
The SOF bit of a transmission frame is detected
The first bit of an error flag is detected during a transmission frame
The TSTAT bit is cleared (0) under the following conditions.
CAN shifted to the bus-off status
Arbitration was lost during a transmission frame
“Recessive” is detected at the 2nd bit of an interframe space.
Initialization mode was shifted to at the first bit of an interframe space
CCERC
CAN Clear Error Counter Bit
0
While in INIT mode, the CAN module error counter C0ERC and the CAN module information register C0INFO
will not be cleared.
1
While in INIT mode, the CAN module error counter C0ERC and the CAN module information register C0INFO
will be cleared.
AL
Arbitration Loss Bit
0
In the “single-shot mode”, no re-transmission when an error occurs.
Transmit message will not be queued for a re-transmission request when arbitration is lost.
1
In the “single-shot mode”, no re-transmission when an error occurs.
Transmit message will be queued for a re-transmission request when arbitration is lost.
Remarks 1. The AL bit is effective only in the “single-shot mode”.
2. If a CAN module operates in the “single-shot mode” and the AL bit is set (1), the interrupt CINTS4
is not generated upon arbitration loss.
VALID
Valid Receive Message Frame Detection Bit
0
No valid message frame reception in the CAN protocol transfer layer since the VALID bit was cleared (0) last
time.
1
Valid message frame reception in the CAN protocol transfer layer since the VALID bit was cleared (0) last time.
Remarks 1. A valid reception does not require acceptance of the message frame in a receive message buffer
(data frame) or transmit message buffer (remote frame).
2. Before switching from INIT mode to any operational mode, the user has to clear the VALID bit (0).
3. If only two CAN nodes are connected to the CAN bus and one of the CAN nodes is in “normal
operating mode” and transmitting message frames while the other CAN node is in “receive-only
mode”, the VALID bit will not be set (1) before the transmitting node becomes error passive.