932S208YFLNT IDT [Integrated Device Technology], 932S208YFLNT Datasheet - Page 15

• Manufacturer Part Number: 932S208YFLNT
• Description: Programmable Timing Control HubTM for Next Gen P4TM Processor
• Manufacturer: IDT [Integrated Device Technology]

The PCI_STOP# signal is on an active low input controlling PCI and SRC outputs. If PCIF (2:0) and SRC clocks can be set to
be free-running through I2C programming. Outputs set to be free-running will ignore both the PCI_STOP pin and the
PCI_STOP register bit.
PCI_STOP# Assertion (transition from '1' to '0')
The clock samples the PCI_STOP# signal on a rising edge of PCIF clock. After detecting the PCI_STOP# assertion low, all
PCI[6:0] and stoppable PCIF[2:0] clocks will latch low on their next high to low transition. After the PCI clocks are latched low,
the SRC clock, (if set to stoppable) will latch high at Iref * 6 (or tristate if Byte 2 Bit 6 = 1) upon its next low to high transition and
the SRC# will latch low as shown below.
IDT
PCI Stop Functionality
PCI_STOP# - De-assertion
The de-assertion of the PCI_Stop# signal is to be sampled on the rising edge of the PCIF free running clock domain. After
detecting PCI_Stop# de-assertion, all PCI[6:0], stoppable PCIF[2:0] and stoppable SRC clocks will resume in a glitch free
manner.
P
ICS932S208
Programmable Timing Control Hub
TM
C
_ I
Programmable Timing Control Hub
S
0
1
T
O
P
#
N
N
C
r o
r o
P
m
m
U
l a
l a
PCIF[2:0] 33MHz
PCIF[2:0] 33MHz
PCI[6:0] 33MHz
PCI[6:0] 33MHz
SRC# 100MHz
N
N
C
SRC# 100MHz
SRC 100MHz
SRC 100MHz
PCI_STOP#
r o
r o
P
PCI_STOP#
U
m
m
l a
l a
#
TM
for Next Gen P4
TM
r o
N
I
e r
S
r o
for Next Gen P4
F
R
* f
m
o l
C
l a
t a
6
Tsu
Tsu
N
S
L
r o
R
o
TM
C
m
w
Processor
#
l a
Tdrive_SRC
TM
Processor
6
6
3
6
6
V
M
M
6
H
H
6
15
z
z
P
3
C
3
L
F I
M
o
P /
w
H
z
I C
U
4
4
S
8
8
B
M
M
D /
H
H
O
z
z
T
1
1
4
4
3 .
3 .
R
1
1
E
8
8
F
M
M
H
H
z
z
N
o
e t
0743G—01/26/10