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Chapter 19
CAN Controller (CAN)
Preliminary User’s Manual U17566EE1V2UM00
19.2.4
Error frame
An error frame is output by a node that has detected an error.
Figure 19-15
Error frame
Note
D: Dominant = 0
R: Recessive = 1
Table 19-7
Definition of error frame fields
No.
Name
Bit
count
Definition
<1>
Error flag 1
6
Error active node:
Outputs 6 dominant-level bits consecutively.
Error passive node: Outputs 6 recessive-level bits consecutively.
If another node outputs a dominant level while one node is outputting
a passive error flag, the passive error flag is not cleared until the
same level is detected 6 bits in a row.
<2>
Error flag 2
0 to 6
Nodes receiving error flag 1 detect bit stuff errors and issues this
error flag.
<3>
Error delimiter
8
Outputs 8 recessive-level bits consecutively.
If a dominant level is detected at the 8th bit, an overload frame is
transmitted from the next bit.
<4>
Error bit
–
The bit at which the error was detected.
The error flag is output from the bit next to the error bit.
In the case of a CRC error, this bit is output following the ACK
delimiter.
<5>
Interframe space/
overload frame
–
An interframe space or overload frame starts from here.
<1>
R
D
<2>
<
3
>
6
b
it
s
0 to 6
b
it
s
8
b
it
s
(<4>)
(<5>)
Interfr
a
me
s
p
a
ce or overlo
a
d fr
a
me
Error delimiter
Error fl
a
g 2
Error fl
a
g 1
Error
b
it
Error fr
a
me
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