ICS954204 Datasheet, PDF (3/16 Pages) Integrated Circuit Systems – Programmable Timing Control HubTM for Mobile P4TM Systems

Integrated
Circuit
Systems, Inc.
ICS954204
Pin Description (Continued)
PIN # PIN NAME
29 GND
30 SRCCLKC5
31 SRCCLKT5
32 CLKREQB#*
33 CLKREQA#*
34 VDDSRC
35 CPUCLKC2_ITP/SRCCLKC7
36 CPUCLKT2_ITP/SRCCLKT7
37 VDDA
38 GNDA
39 IREF
40 CPUCLKC1
41 CPUCLKT1
42 VDDCPU
43 CPUCLKC0
44 CPUCLKT0
45 GND
46 SCLK
47 SDATA
48 VDDREF
49 X2
50 X1
51 GND
52 REFOUT
53 FSLC/TEST_SEL
54 CPU_STOP#
55 PCI/SRC_STOP#
56 PCICLK2
*Pins 32 and 33 have pull-ups.
0933D—03/16/05
Type
PWR
OUT
OUT
IN
IN
PWR
OUT
OUT
PWR
PWR
IN
Pin Description
Ground pin.
Complement clock of differential SRC clock pair.
True clock of differential SRC clock pair.
Output enable for PCI Express (SRC) outputs. SMBus selects which outputs
are controlled.
0 = enabled, 1 = tri-stated
Output enable for PCI Express (SRC) outputs. SMBus selects which outputs
are controlled.
0 = enabled, 1 = tri-stated
Supply for SRC clocks, 3.3V nominal
Complementary clock of CPU_ITP/SRC differential pair CPU_ITP/SRC
output. These are current mode outputs. External resistors are required for
voltage bias. Selected by ITP_EN input.
True clock of CPU_ITP/SRC differential pair CPU_ITP/SRC output. These
are current mode outputs. External resistors are required for voltage bias.
Selected by ITP_EN input.
3.3V power for the PLL core.
Ground pin for the PLL core.
This pin establishes the reference current for the differential current-mode
output pairs. This pin requires a fixed precision resistor tied to ground in
order to establish the appropriate current. 475 ohms is the standard value.
OUT
OUT
PWR
OUT
OUT
PWR
IN
I/O
PWR
OUT
IN
PWR
OUT
IN
Complementary clock of differential pair CPU outputs. These are current
mode outputs. External resistors are required for voltage bias.
True clock of differential pair CPU outputs. These are current mode outputs.
External resistors are required for voltage bias.
Supply for CPU clocks, 3.3V nominal
Complementary clock of differential pair CPU outputs. These are current
mode outputs. External resistors are required for voltage bias.
True clock of differential pair CPU outputs. These are current mode outputs.
External resistors are required for voltage bias.
Ground pin.
Clock pin of SMBus circuitry, 5V tolerant.
Data pin for SMBus circuitry, 5V tolerant.
Ref, XTAL power supply, nominal 3.3V
Crystal output, Nominally 14.318MHz
Crystal input, Nominally 14.318MHz.
Ground pin.
Reference Clock output
3.3V tolerant input for CPU frequency selection. Low voltage threshold
inputs, see input electrical characteristics for Vil_FS and Vih_FS values.
TEST_Sel: 3-level latched input to enable test mode.
Refer to Test Clarification Table
IN
IN
OUT
Stops all CPUCLK, except those set to be free running clocks
Stops all PCICLKs and SRCCLKs besides the free-running clocks at logic 0
level, when input low
PCI clock output.
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