183
ATmega16M1/32M1/64M1 [DATASHEET]
8209E–AVR–11/2012
Bit 7 – DLCW: Data Length Code Warning
The incoming message does not have the DLC expected. Whatever the frame type, the DLC field of the CANCD-
MOB register is updated by the received DLC.
Bit 6 – TXOK: Transmit OK
This flag can generate an interrupt. It must be cleared using a read-modify-write software routine on the whole
CANSTMOB register.
The communication enabled by transmission is completed. TxOK rises at the end of EOF field. When the controller
is ready to send a frame, if two or more message objects are enabled as producers, the lower MOb index (0 to 14)
is supplied first.
Bit 5 – RXOK: Receive OK
This flag can generate an interrupt. It must be cleared using a read-modify-write software routine on the whole
CANSTMOB register.
The communication enabled by reception is completed. RxOK rises at the end of the 6
th bit of EOF field. In case of
two or more message object reception hits, the lower MOb index (0 to 14) is updated first.
Bit 4 – BERR: Bit Error (Only in Transmission)
This flag can generate an interrupt. It must be cleared using a read-modify-write software routine on the whole
CANSTMOB register.
The bit value monitored is different from the bit value sent.
Exceptions: the monitored recessive bit sent as a dominant bit during the arbitration field and the acknowledge slot
detecting a dominant bit during the sending of an error frame.
Bit 3 – SERR: Stuff Error
This flag can generate an interrupt. It must be cleared using a read-modify-write software routine on the whole
CANSTMOB register.
Detection of more than five consecutive bits with the same polarity. This flag can generate an interrupt.
Bit 2 – CERR: CRC Error
This flag can generate an interrupt. It must be cleared using a read-modify-write software routine on the whole
CANSTMOB register.
The receiver performs a CRC check on every de-stuffed received message from the start of frame up to the data
field. If this checking does not match with the de-stuffed CRC field, a CRC error is set.
Bit 1 – FERR: Form Error
This flag can generate an interrupt. It must be cleared using a read-modify-write software routine on the whole
CANSTMOB register.
The form error results from one or more violations of the fixed form in the following bit fields:
CRC delimiter
Acknowledgment delimiter
EOF
Bit 0 – AERR: Acknowledgment Error
This flag can generate an interrupt. It must be cleared using a read-modify-write software routine on the whole
CANSTMOB register.