175
ATmega16M1/32M1/64M1 [DATASHEET]
8209E–AVR–11/2012
– 0 - standby mode: The on-going transmission (if exists) is normally terminated and the CAN channel is
frozen (the CONMOB bits of every MOb do not change). The transmitter constantly provides a recessive
level. In this mode, the receiver is not enabled but all the registers and mailbox remain accessible from
CPU. In this mode, the receiver is not enabled but all the registers and mailbox remain accessible from
CPU
Note:A standby mode applied during a reception may corrupt the on-going reception or set the controller in a wrong
state. The controller will restart correctly from this state if a software reset (SWRES) is applied. If no reset is con-
sidered, a possible solution is to wait for a lake of a receiver busy (RXBSY) before to enter in stand-by mode. The
best solution is first to apply an abort request command (ABRQ) and then wait for the lake of the receiver busy
(RXBSY) before to enter in stand-by mode. In any cases, this standby mode behavior has no effect on the CAN
bus integrity.
– 1 - enable mode: The CAN channel enters in enable mode once 11 recessive bits has been read
Bit 0 – SWRES: Software Reset Request
This auto resettable bit only resets the CAN controller.
–0 - no reset
– 1 - reset: this reset is “ORed” with the hardware reset
19.10.2
CANGSTA – CAN General Status Register
Bit 7 – Res: Reserved
This bit is reserved and will always read as zero.
Bit 6 – OVRG: Overload Frame Flag
This flag does not generate an interrupt.
– 0 - no overload frame
– 1 - overload frame: set by hardware as long as the produced overload frame is sent
Bit 5 – Res: Reserved
This bit is reserved and will always read as zero.
Bit 4 – TXBSY: Transmitter Busy
This flag does not generate an interrupt.
– 0 - transmitter not busy
– 1 - transmitter busy: set by hardware as long as a frame (data, remote, overload or error frame) or an
ACK field is sent. Also set when an inter frame space is sent
Bit 3 – RXBSY: Receiver Busy
This flag does not generate an interrupt.
– 0 - receiver not busy
– 1 - receiver busy: set by hardware as long as a frame is received or monitored
Bit 2 – ENFG: Enable Flag
This flag does not generate an interrupt.
Bit
7654
321
0
-
OVRG
-
TXBSY
RXBSY
ENFG
BOFF
ERRP
CANGSTA
Read/write
-
R
-
R
Initial value
-
0
-
0