Rainbow Electronics CAN интерфейс - Manual (Page 32)

BOSCH
ROBERT BOSCH GmbH, Postfach 50, D-7000 Stuttgart 1
Sep. 1991
Part A - page 30
SYNCHRONIZATION RULES
HARD SYNCHRONIZATION and RESYNCHRONIZATION are the two forms of
SYNCHRONIZATION. They obey the following rules:
1. Only one SYNCHRONIZATION within one bit time is allowed.
2. An edge will be used for SYNCHRONIZATION only if the value detected at the
previous SAMPLE POINT (previous read bus value) differs from the bus value
immediately after the edge.
3. HARD SYNCHRONIZATION is performed whenever there is a ’recessive’ to
’dominant’ edge during BUS IDLE.
4. All other ’recessive’ to ’dominant’ edges (and optionally ’dominant’ to ’recessive’
edges in case of low bit rates) fulfilling the rules 1 and 2 will be used for
RESYNCHRONIZATION with the exception that a node transmitting a dominant bit
will not perform a RESYNCHRONIZATION as a result of a ’recessive’ to ’dominant’
edge with a positive PHASE ERROR, if only ’recessive’ to ’dominant’ edges are
used for resynchronization.
Bit Timing