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Chapter 16
CAN Controller
User’s Manual U16504EE1V1UD00
(b) Error counter
Error counter counts up when an error has occurred, and counts down upon successful
transmission and reception. The error counters are updated during the first bit of an error flag.
Table 16-14:
Error Counter
(c) Overload frame
In case the recessive level of first intermission bit is driven to dominant level, an overload frame
occurs on the bus. Upon detection of an overload frame any transmit request will be postponed
until the bus becomes idle.
State
Transmission Error
Counter (TEC)
Reception Error
Counter (REC)
Reception node detects an error (except bit error in the active
error flag or overload flag).
No change
+1
Reception node detects dominant level following the error flag
of the own error frame.
No change
+8
Transmission node transmits an error flag.
Exception:
1. ACK error is detected in the error passive state and domi-
nant level is not detected in the passive error flag sent.
2. Stuff error generation in arbitration field.
+8
No change
Bit error detection during active error flag and overload flag
when transmitting node is in error active state.
+8
No change
Bit error detection during active error flag and overload flag
when receiving node is in error active state.
No change
+8
When the node detects fourteen continuous dominant bits
counted from the beginning of the active error flag or the over-
load flag, and every time, eight subsequent dominant bits after
that are detected.
Every time when the node detects eight continuous dominant
bits after the passive error flag.
+8
+8
When the transmitting node has completed to sent without
error.
-1
(-0 when
error counter = 0)
No change
When the reception node has completed to receive without
error.
No change
-1 (1
≤
REC
≤
127)
–0 (REC = 0)
119-127 (REC > 127)