Datasheet

20.8.2. Error types
• BERR: Bit error. The bit value which is monitored is different from the bit value sent
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
• 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:
– CRC delimiter
– acknowledgment delimiter
– end-of-frame
– error delimiter
– overload delimiter
• AERR: Acknowledgment error (Tx only). No detection of the dominant bit in the acknowledge slot
Figure 20-13. Error detection procedures in a data frame.
Identifier
Message Data
RTR
ACK error
Form error
Stuff error
Bit error
CRC error
Form error
Stuff error
Bit error
ACK EOF
SOF
CRC
del.
ACK
del.
inter.Control
CRC
Tx
Rx
Arbitration
20.8.3. Error setting
The CAN channel can detect some errors on the CAN network.
• In transmission:
The error is set at MOb level
• In reception:
- The identified has matched:
The error is set at MOb level
- The identified has not or not yet matched:
The error is set at general level
After detecting an error, the CAN channel sends an error frame on network. If the CAN channel detects
an error frame on network, it sends its own error frame.
20.9. Interrupts
20.9.1. Interrupt organization
The different interrupts are:
• Interrupt on receive completed OK
• Interrupt on transmit completed OK
Atmel ATmega16M1/32M1/64M1 [DATASHEET]
Atmel-8209F-ATmega16M1/32M1/64M1_Datasheet_Complete-10/2016
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