AT90CAN128-16AE ATMEL Corporation, AT90CAN128-16AE Datasheet - Page 241

• Manufacturer Part Number: AT90CAN128-16AE
• Description: 8-bit Avr Microcontroller With 128K Bytes of Isp Flash And CAN Controller.flash (Kbytes) 128 Vcc (V) 2.7-5.5 EEPROM (Kbytes) 4 SRAM (bytes) 4K CAN (mess. Obj.) 15
• Manufacturer: ATMEL Corporation

Error Management
Fault Confinement
Error Types
4250C–CAN–03/04
The CAN channel may be in one of the three following states:
•
•
•
For fault confinement, a transmit error counter (TEC) and a receive error counter (REC)
are implemented. BOFF and ERRP bits give the information of the state of the CAN
channel. Setting BOFF to one may generate an interrupt.
Figure 119. Line Error Mode
Note:
•
•
•
•
Error active (default):
The CAN channel takes part in bus communication and can send an active error
frame when the CAN macro detects an error.
Error passive:
The CAN channel cannot send an active error frame. It takes part in bus
communication, 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.
Bus off:
The CAN channel is not allowed to have any influence on the bus.
BERR: Bit error. The bit value which is monitored is different from the bit value sent.
SERR: Stuff error. Detection of more than five consecutive bit with the same polarity.
CERR: CRC error (Rx only). The receiver performs a CRC check on every destuffed
received message from the start of frame up to the data field. If this checking does
not match with the destuffed CRC field, an CRC error is set.
FERR: Form error. The form error results from one (or more) violations of the fixed
form of the following bit fields:
–
–
–
–
More than one REC/TEC change may apply during a given message transfer.
Note: Exceptions:
- Recessive bit sent monitored as dominant bit during the arbitration field and the
acknowledge slot.
- Detecting a dominant bit during the sending of an error frame.
CRC delimiter
acknowledgement delimiter
end-of-frame
error delimiter
ERPP = 1
BOFF = 0
Passive
Error
TEC > 127 or
ERPP = 0
BOFF = 0
REC > 127
TEC
REC
127 and
127
BOFFIT interrupt
TEC > 255
Reset
Active
Error
ERPP = 0
BOFF = 1
of 11 consecutive
128 occurrences
recessive bit
AT90CAN128
Bus
Off
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