16.11 MOb Registers
The MOb registers has no initial (default) value after RESET.
16.11.1 CAN MOb Status Register - CANSTMOB
Bit
7
DLCW
R/W
-
6
TXOK
R/W
-
5
RXOK
R/W
-
4
BERR
R/W
-
3
SERR
R/W
-
2
CERR
R/W
-
1
FERR
R/W
-
0
AERR CANSTMOB
Read/Write
Initial Value
R/W
-
• 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 CANCDMOB
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 6th 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
ATmega16/32/64/M1/C1 [DATASHEET]
167
7647O–AVR–01/15
MICROCHIP [ MICROCHIP ]
