English
Language : 

ICS952601 Datasheet, PDF (21/25 Pages) Integrated Circuit Systems – Programmable Timing Control Hub™ for Next Gen P4™ processor
ICS952601
Programmable Timing Control HubTM for Next Gen P4TM Processor
SRC Clock Tristate Timing
The following diagrams illustrate SRC clock timing during PCI_Stop# and PwrDwn# modes with SRC_Pwrdwn and
SRC_Stop tristate control bits set to driven or tristate in byte 2 of the control register.
SRC_Stop = Driven, SRC_Pwrdwn = Driven
PCI_Stop#
PCI (Free Running)
PWRDWN#
CPU (Free Running)
CPU# (Free Running)
SRC (Stoppable)
SRC# (Stoppable)
1.8mS
1 PCI
clock max
Notes:
1. When both bits (SRC_Stop & SRC_Pwrdown tristate bits) are set to driven, the clock chip will never tristate the SRC output
clock (assuming clock's OE bit is set to "1")
SRC_Stop = Tristate, Pwrdwn = Tristate
PCI_Stop#
PCI (Free Running)
PWRDWN#
CPU (Free Running)
CPU# (Free Running)
1.8mS
SRC (Stoppable)
SRC# (Stoppable)
1 PCI
clock max
Notes:
1. When SRC_Stop and SRC_Pwrdwn bits are set to tristate, the clock chip will tristate outputs during the assertion of
PCI_Stop# and PWRDWN#.
2. Tristate outputs are pulled low by output termination resistors as shown here.
IDTTM Progammable Timing Control HubTM for Next Gen P4TM Processor
21
701J—01/25/10