Rainbow Electronics CAN интерфейс - Manual (Page 19)

BOSCH
ROBERT BOSCH GmbH, Postfach 50, D-7000 Stuttgart 1
Sep. 1991
Part A - page 17
of equal polarity, beginning at the start of the PASSIVE ERROR FLAG. The PASSIVE
ERROR FLAG is complete when these 6 equal bits have been detected.
ERROR DELIMITER
The ERROR DELIMITER consists of eight ’recessive’ bits.
After transmission of an ERROR FLAG each station sends ’recessive’ bits and
monitors the bus until it detects a ’recessive’ bit. Afterwards it starts transmitting seven
more ’recessive’ bits.
3.1.4 OVERLOAD FRAME
The OVERLOAD FRAME contains the two bit fields OVERLOAD FLAG and
OVERLOAD DELIMITER.
There are two kinds of OVERLOAD conditions, which both lead to the transmission of
an OVERLOAD FLAG:
1. The internal conditions of a receiver, which requires a delay of the next DATA
FRAME or REMOTE FRAME.
2. Detection of a ’dominant’ bit during INTERMISSION.
The start of an OVERLOAD FRAME due to OVERLOAD condition 1 is only allowed to
be started at the first bit time of an expected INTERMISSION, whereas OVERLOAD
FRAMEs due to OVERLOAD condition 2 start one bit after detecting the ’dominant’ bit.
At most two OVERLOAD FRAMEs may be generated to delay the next DATA or
REMOTE FRAME.
End of Frame or
Overload
Overload Delimiter
Inter
Space or
OVERLOAD FRAME
Overload
Frame
superposition of
Overload Flags
Flag
Frame
Error Delimiter or
Overload Delimiter
Overload Frame