Rainbow Electronics CAN интерфейс - Manual (Page 56)

BOSCH
ROBERT BOSCH GmbH, Postfach 300240, D-7000 Stuttgart 30
Sep. 1991
Part B - page 54
Note:
If a CAN node has a message waiting for transmission and it samples a dominant
bit at the third bit of INTERMISSION, it will interpret this as a START OF FRAME
bit, and, with the next bit, start transmitting its message with the first bit of its
IDENTIFIER without first transmitting a START OF FRAME bit and without
becoming receiver.
BUS IDLE
The period of BUS IDLE may be of arbitrary length. The bus is recognized to be free
and any station having something to transmit can access the bus. A message, which is
pending for transmission during the transmission of another message, is started in the
first bit following INTERMISSION.
The detection of a ’dominant’ bit on the bus is interpreted as a START OF FRAME.
SUSPEND TRANSMISSION
After an ’error passive’ station has transmitted a message, it sends eight ’recessive’
bits following INTERMISSION, before starting to transmit a further message or
recognizing the bus to be idle. If meanwhile a transmission (caused by another station)
starts, the station will become receiver of this message.
Interframe Space