CY28325-2 Datasheet, PDF (1/19 Pages) Cypress Semiconductor – FTG for VIA Pentium 4 Chipsets

PRELIMINARY
CY28325-2
FTG for VIA Pentium 4 Chipsets
Features
• Spread Spectrum Frequency Timing Generator for VIA
Pentium 4 Chipsets
• Programmable clock output frequency with less than
1 MHz increment
• Integrated fail-safe Watchdog Timer for system
recovery
• Automatically switch to hardware-selected or software-
programmed clock frequency when Watchdog Timer
time-out
• Capable of generate system RESET after a Watchdog
Timer time-out occurs or a change in output frequency
via SMBus interface
• Support SMBus Byte Read/Write and Block Read/Write
operations to simplify system BIOS development
• Vendor ID and Revision ID support
• Programmable-drive strength support
• Programmable-output skew support
• Three copies of 66-MHz output
• Power management control inputs
• Available in 48-pin SSOP
CPU
AGP
PCI
REF
APIC
48M 24_48M
x3
x3
x9
x1
x2
x1
x1
Block Diagram
X1
X2
*(FS0:4)
VTT_PWRGD#
*CPU_STOP#
*MULTSEL1
XTAL
OSC
PLL Ref Freq
PLL 1
Divider
Network
Stop
Clock
Control
PD#
*PCI_STOP#
PLL2
SDATA
SCLK
SMBus
Logic
Stop
Clock
Control
2
VDD_REF
REF
Pin Configuration^[1]
SSOP-48
VDD_CPU_CS (2.5V)
CPUT_CS, CPUC_CS
*FS4/REF
1
48
VDD_CPU (3.3V)
VDD_REF 2
47
CPUT_0, CPUC_0
GND_REF 3
46
X1 4
45
X2 5
44
VDD_48MHz 6
43
VDD_APIC
*FS3/48MHz 7
42
APIC0:1
*FS2/24_48MHz 8
41
GND_48MHz 9
40
VDD_AGP
*FS0/PCI_F 10
39
AGP0:2
*FS1/PCI1 11
38
*MULT_SEL1/PCI2 12
37
VDD_PCI
PCI_F
GND_PCI 13
36
PCI3 14
35
PCI4 15
34
PCI1:8
VDD_PCI 16
33
PCI5 17
32
PCI6 18
31
PCI7 19
30
GND_PCI 20
29
PCI8 21
28
*PD# 22
27
AGP0 23
26
VDD_48MHz
VDD_AGP 24
25
48MHz
VDD_APIC
GND_APIC
APIC0
APIC1
GND_CPU
VDD_CPU_CS(2.5V)
CPUT_CS_F
CPUC_CS_F
CPUT_0
CPUC_0
VDD_CPU(3.3V)
IREF
GND_CPU
CPUT_1
CPUC_1
VTT_PWRGD#
CPU_STOP#*
PCI_STOP#*
RST#
SDATA
SCLK
AGP2
AGP1
GND_AGP
24_48MHz
RST#
Note:
1. Pins marked with [*] have internal pull-up resistors. Pins
marked with[^] have internal pull-down resistors.
Cypress Semiconductor Corporation • 3901 North First Street • San Jose • CA 95134 • 408-943-2600
Document #: 38-07119 Rev. **
Revised February 27, 2002