at89c51cc02ua-tdsum ATMEL Corporation, at89c51cc02ua-tdsum Datasheet - Page 86

• Manufacturer Part Number: at89c51cc02ua-tdsum
• Description: At89c51cc02, T89c51cc02 Enhanced 8-bit Microcontroller With Can Controller And Flash
• Manufacturer: ATMEL Corporation

Fault Confinement
86
AT/T89C51CC02
With respect to fault confinement, a unit may be in one of the three following status:
•
•
•
An error active unit takes part in bus communication and can send an active error frame
when the CAN macro detects an error.
An error passive unit cannot send an active error frame. It takes part in bus communica-
tion, but when an error is detected, a passive error frame is sent. Also, after a
transmission, an error passive unit will wait before initiating further transmission.
A bus off unit is not allowed to have any influence on the bus.
For fault confinement, two error counters (TEC and REC) are implemented.
See CAN Specification for details on Fault confinement.
Figure 42. Line Error Mode
Error active
Error passive
Bus off
ERRP = 1
BOFF = 0
REC>127
TEC>127
or
ERRP = 0
BOFF = 0
Passive
Error
REC<127
TEC<127
TEC>255
and
Active
Error
Init.
Bus
Off
128 Occurrences
11 Consecutive
Recessive
bit
of
REC: Receive Error Counter
TEC: Transmit Error Counter
ERRP = 0
BOFF = 1
4126L–CAN–01/08