Intel 87C196CB Manual De Usuario

7-11

t

SYNC

_

SEG

 

This time segment is equivalent to SYNC_SEG in the CAN protocol. Its length is one time 
quantum. 

t

TSEG

1

 

This time segment is equivalent to the sum of PROP_SEG and PHASE_SEG1 in the CAN 
protocol. Its length is specified by the TSEG1 field in bit timing register 1. To allow for resyn-
chronization, the sample point can be moved (t

TSEG1

 or t

TSEG2

 can be shortened and the other 

lengthened) by 1 to 4 time quanta, depending on the programmed value of the SJW field in bit 
timing register 0. 

The CAN controller samples the bus once or three times, depending on the value of the 
sampling mode (SPL) bit in bit timing register 0. In three-sample mode, the hardware 
lengthens t

TSEG1

 by 2 time quanta to allow time for the additional two bus samples. In this 

case, the “sample point” shown in Figure 7-5 is the time of the third sample; the first and 
second samples occur 2 and 1 time quanta earlier, respectively.

t

TSEG

2

 

This time segment is equivalent to PHASE_SEG2 in the CAN protocol. Its length is specified 
by the TSEG2 field in bit timing register 1. To allow for resynchronization, the sample point 
can be moved (t

TSEG1

 or t

TSEG2

 can be shortened and the other lengthened) by 1 to 4 time 

quanta, depending on the programmed value of the SJW field in bit timing register 0. 

TSEG1

Sample

Transmit

1 tq

Bit Time

(TSEG1 + 1)tq

t

A2602-01

TSEG2

t

SYNC
_SEG

t

(TSEG2 + 1)tq