Intel 8XC196NT, 87C196CB Bit Timing, Syncseg Propseg PHASESEG1 PHASESEG2, Symbol Definition

87C196CB SUPPLEMENT

7.3.5Bit Timing

A message object consists of a series of bits transmitted in consecutive bit times. The CAN pro- tocol specifies a bit time composed of four separate, nonoverlapping time segments: a synchro- nization delay segment, a propagation delay segment, and two phase delay segments (Figure 7-4 and Table 7-8). The CAN controller implements a bit time as three segments, combining

PROP_SEG and PHASE_SEG1 into tTSEG1 (Figure 7-5 and Table 7-9). This implementation is identical to that of the 82527 CAN peripheral.

Nominal Bit Time

SYNC_SEG

PROP_SEG

PHASE_SEG1

PHASE_SEG2

	Sample	Transmit
		A2603-01
	Figure 7-4. A Bit Time as Specified by the CAN Protocol
	Table 7-8. CAN Protocol Bit Time Segments
Symbol	Definition
SYNC_SEG	The synchronization delay segment allows for synchronization of the various nodes on
	the bus. An edge is expected to lie within this segment.
PROP_SEG	The propagation delay segment compensates for the physical delay times within the
	network. It is twice the sum of the signal’s propagation time on the bus line, the input
	comparator delay, and the output driver delay. The factor of two accounts for the
	requirement that all nodes monitor all bus transmissions for errors.
PHASE_SEG1	This segment compensates for edge phase errors. It can be lengthened or shortened by
	resynchronization.
PHASE_SEG2	This segment compensates for edge phase errors. It can be lengthened or shortened by
	resynchronization.

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