P80C592 Philips Semiconductors, P80C592 Datasheet - Page 53

• Manufacturer Part Number: P80C592
• Description: 8-bit microcontroller with on-chip CAN
• Manufacturer: Philips Semiconductors

Philips Semiconductors
13.5.19.3 Time Segment 2 (TSEG2)
This time segment provides:
TSEG2 is programmable from 1 to 8 system clock cycles
(see Section 13.5.10).
13.5.19.4 Synchronisation Jump Width (SJW)
SJW defines the maximum number of clock cycles (t
period may be reduced or increased by one
resynchronization. SJW is programmable from 1 to 4
system clock cycles, see Section 13.5.2.
13.5.19.5 Propagation Delay Time (t
The Propagation Delay Time is:
t
13.5.19.6 Bit Timing Restrictions
Restrictions on the configuration of the bit timing are based
on internal processing. The restrictions are:
The three sample mode (SAM = HIGH) has the effect of
introducing a delay of one system clock cycle on the
bus-line. This must be taken into account for the correct
calculation of TSEG1 and TSEG2:
13.5.20 S
Synchronization is performed by a state machine which
compares the incoming edge with its actual bit timing and
adapts the bit timing by hard synchronization or
resynchronization.
1996 Jun 27
t
prop
prop
Additional time at the sample point for calculation of the
subsequent bit levels (e.g. arbitration)
Synchronization buffer segment directly after the
sample point.
t
t
t
t
t
t
8-bit microcontroller with on-chip CAN
TSEG2
TSEG2
TSEG1
TSEG1
TSEG1
TSEG2
is rounded up to the nearest multiple of t
=
2
+
+
YNCHRONIZATION
2t
t
t
t
t
3t
SJW
SEG2
SJW
SJW
input comparator delay
output driver delay
physical bus delay
SCL
SCL
+ t
+ t
.
prop
prop
.
+ 2t
SCL
.
prop
)
SCL
.
SCL
) a
53
This type of synchronization occurs only at the beginning
of a message.
The CAN-controller synchronizes on the first incoming
recessive-to-dominant edge of a message (being the
leading edge of a message's Start-Of-Frame bit;
see Section 13.6.2.
Resynchronization occurs during the transmission of a
message's bit stream to compensate for:
As a result of resynchronization either t
increased by up to a maximum of t
decreased by up to a maximum of t
TSEG1, TSEG2 and SJW are the programmed numerical
values.
The phase error (e) of an edge is given by the position of
the edge relative to SYNCSEG, measured in system clock
cycles (t
The value of the phase error is defined as:
The effect of resynchronization is:
Variations in individual CAN-controller oscillator
frequencies
Changes introduced by switching from one transmitter
to another (e.g. during arbitration).
t
t
e = 0, if the edge occurs within SYNCSEG
e
e
The same as that of a hard synchronization, if the
magnitude of the phase error (e) is less or equal to the
programmed value of t
To increase a bit period by the amount of t
phase error is positive and the magnitude of the phase
error is larger than t
To decrease a bit period by the amount of t
phase error is negative and the magnitude of the phase
error is larger than t
TSEG1
TSEG2
0, if the edge occurs within TSEG1
0, if the edge occurs within TSEG2.
SCL
t
t
SCL
SCL
).
[(TSEG1 + 1) + (SJW + 1)]
[(TSEG2 + 1)
SJW
SJW
SJW
.
(SJW + 1)].
SJW
SJW
Product specification
or t
:
TSEG1
P8xC592
TSEG2
SJW
may be
SJW
may be
, if the
, if the