253
7679H–CAN–08/08
AT90CAN32/64/128
– 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.
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 considered, 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 behav-
ior 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
CAN General Status Register - CANGSTA
• Bit 7 – Reserved Bit
This bit is reserved for future use.
• 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 – Reserved Bit
This bit is reserved for future use.
• 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
Bit
7
6
5
4
3
2
1
0
-
OVRG
-
TXBSY
RXBSY
ENFG
BOFF
ERRP
CANGSTA
Read/Write
-
R
-
R
R
R
R
R
Initial Value
-
0
-
0
0
0
0
0
Содержание AVR AT90CAN128
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