Fujitsu FR81S User Manual
CHAPTER 41: CAN
4. Registers
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER
: CAN
FUJITSU SEMICONDUCTOR CONFIDENTIAL
20
[bit4]: Successful message reception bit
RxOk
Function
0
Indicates successful message communication is not performed on the CAN bus or the
bus is in the idle state. [Initial value]
1
Indicates successful message communication is performed on the CAN bus.
[bit3]: Successful message transmission bit
TxOk
Function
0
Indicates the bus is in the idle state or successful message transmission is not
performed. [Initial value]
1
Indicates successful message transmission is performed.
Note:
The RxOk and TxOk bits are cleared only with "0" writing.
[bit2 to bit0] : Last error code bits
The LEC bit holds the code that indicates the last error occurred on the CAN bus. This bit is cleared to "0"
when a message transfer (reception/transmission) completes without error. The undetected code "111
B
" can
be used for checking the code update.
LEC[2:0]
State
Function
000
Normal
Indicates transmission or reception is performed successfully.
[Initial value]
001
Stuff error
Indicates more than 6 bits of dominant or recessive is detected
continuously in a message.
010
Form error
Indicates the fixed format segment of a received frame is detected as
incorrect.
011
Ack error
Indicates the transmission message is not acknowledged by other
nodes.
100
Bit1 error
Indicates dominant was detected even though recessive was sent with
the message transmission data other than arbitration field.
101
Bit0 error
Indicates recessive was detected even though dominant was sent with
the message transmission data.
This bit is set every time 11 bits of recessive is detected during the bus
recovery. Reading this bit allows the monitoring of the bus recovery
sequence.
110
CRC error
Indicates that CRC data and CRC result calculated for a received
message did not match.
111
Undetected
Indicates no transmission or reception is performed during the period
when LEC reads "111
B
" after "111
B
" is set to the LEC bit.(bus idle
status)
MB91520 Series
MN705-00010-1v0-E
1713