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M16C/5L Group, M16C/56 Group
23.1.12 CAN0 Transmit FIFO Control Register (C0TFCR)
CAN0 Transmit FIFO Control Register
b7 b6 b5 b4
b3
b2
b1
0
Note:
1. Write to the C0TFCR register in CAN operation mode or CAN halt mode.
Figure 23.14 C0TFCR Register
23.1.12.1 TFE Bit
When the TFE bit is set to 1, the transmit FIFO is enabled.
When this bit is set to 0, the transmit FIFO becomes empty (TFEST bit = 1) and then unsent messages
from the transmit FIFO are lost as described below:
• If a message from the transmit FIFO is not scheduled for the next transmission or during
transmission.
• Following the completion of transmission, a CAN bus error, CAN bus arbitration lost, or entry to
CAN halt mode if a message from the transmit FIFO is scheduled for the next transmission or
already during transmission.
Before setting the TFE bit to set to 1 again, ensure that the TFEST bit has been set to 1.
After setting the TFE bit to 1, write transmit data into the C0MB24 register.
Do not set this bit to 1 in normal mailbox mode (MBM bit in the C0CTLR register = 0).
23.1.12.2 TFUST Bit
The TFUST bit indicates the number of unsent messages in the transmit FIFO.
After the TFE bit is set to 0, the value of the TFUST bit is initialized to 000b when transmission abort or
transmission is completed.
R01UH0127EJ0110 Rev.1.10
Sep 01, 2011
b0
Symbol
C0TFCR
Bit Symbol
Transmit FIFO
TFE
Enable Bit
Transmit FIFO
TFUST
Unsent Message Number
Status Bit
—
No register bit; If necessary, set to 0. The read value is 0.
(b4)
—
Reserved
(b5)
Transmit FIFO Full
TFFST
Status Bit
Transmit FIFO Empty
TFEST
Status Bit
(1)
Address
D7CAh
Bit Name
0: Transmit FIFO disabled
1: Transmit FIFO enabled
b3 b2 b1
0 0 0 : No unsent message
0 0 1 : 1 unsent message
0 1 0 : 2 unsent messages
0 1 1 : 3 unsent messages
1 0 0 : 4 unsent messages
1 0 1 : Reserved
1 1 0 : Reserved
1 1 1 : Reserved
If necessary, set to 0. The read value
is undefined.
0: Transmit FIFO is not full
1: Transmit FIFO is full
(4 unsent messages)
0: Unsent message in transmit FIFO
1: No unsent message in transmit
FIFO
23. CAN Module
Reset Value
1000 0000b
Function
RW
RW
RO
—
RO
RO
RO
Page 574 of 803
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