MEGA128CAN Datasheet, PDF (255/413 Pages) ATMEL Corporation – Microcontroller WITH 128K BYTES OF ISP FLASH AND CAN CONTROLLER

AT90CAN128
• Bit 5 – RXOK: Receive OK
This flag can generate an interrupt. It must be cleared using a read-modify-write soft-
ware routine on the whole CANSTMOB register.
The communication enabled by reception is completed. In the case of two or more mes-
sage 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 soft-
ware 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 soft-
ware routine on the whole CANSTMOB register.
Detection of more than five consecutive bits with the same polarity. This flag can gener-
ate an interrupt.
• Bit 2 – CERR: CRC Error
This flag can generate an interrupt. It must be cleared using a read-modify-write soft-
ware 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 soft-
ware 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 soft-
ware routine on the whole CANSTMOB register.
No detection of the dominant bit in the acknowledge slot.
4250E–CAN–12/04
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