
FTG for VIA K7 Series Chipset with
Programmable Output Frequency
CY28312B-2
Cypress Semiconductor Corporation
Document #: 38-07596 Rev. **
3901 North First Street
San Jose
,
CA 95134
408-943-2600
Revised December 1, 2003
Features
Single-chip FTG solution for VIA K7 Series chipsets
Programmable clock output frequency with less than
1-MHz increment
Integrated fail-safe Watchdog timer for system
recovery
Automatically switch to HW-selected or
SW-programmed clock frequency when Watchdog
timer time-out
Capable of generating 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 for PCI output clocks
Programmable output skew between CPU, AGP and PCI
Maximized electromagnetic interference (EMI)
suppression using Cypress’s Spread Spectrum
technology
Low jitter and tightly controlled clock skew
Two pairs of differential CPU clocks
Eleven copies of PCI clocks
Three copies of 66-MHz outputs
Two copies of 48-MHz outputs
Three copies of 14.31818-MHz reference clocks
One RESET output for system recovery
Power management control support
Key Specifications
CPU outputs cycle-to-cycle jitter: ............................... 250 ps
48-MHz, 3V66, PCI outputs
cycle-to-cycle jitter: ..................................................... 250 ps
CPU 3V66 output skew:.............................................. 200 ps
48-MHz output skew:.................................................. 250 ps
PCI output skew:......................................................... 500 ps
Note:
1. Internal 100K pull-up resistors present on inputs marked with *. Design should not rely solely on internal pull-up resistor to set I/O pins HIGH.
Block Diagram
Pin Configuration
[1]
VDD_REF
VDD_CPU
PCI1:8
OSC
PLL REF FREQ
PLL 1
X2
X1
REF2
REF1/FS1*
REF0/FS0*
24_48MHz/FS4*
PLL2
VDD_48MHz
SMBus
Logic
SDATA
SCLK
AGP0:2
CPUT0,CPUC0
CPUT_CS,CPUC_CS
VDD_AGP
Divider,
Delay,
and
Phase
Control
Logic
3
VDD_PCI
PCI0/SEL24_48#*
2
RST#
PCI9_E
/2
(FS0:4)
5
48MHz/FS3*
VDD_REF
GND_REF
X1
X2
VDD_48MHz
*FS2/48MHz
*FS3/24_48MHz
GND_48MHz
*FS4/PCI_F
*SEL24_48#/PCI0
PCI1
GND_PCI
PCI2
PCI3
VDD_PCI
PCI4
PCI5
PCI6
GND_PCI
PCI7
PCI8
PCI9_E
VDD_PCI
RST#
C
REF0/FS0*
REF1/FS1*
REF2
REF_STOP#*
AGP_STOP#*
GND_CPU
CPUT0
CPUC0
VDD_CPU
CPUT_CS
CPUC_CS
GND_CPU
CPU_STOP#*
PCI_STOP#*
PD#*
VDD_CORE
GND_CORE
SDATA
SCLK
GND_AGP
AGP2
AGP1
AGP0
VDD_AGP
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
SEL24_48#*
PD#
CPU_STOP#
PCI_STOP#
AGP_STOP#
REF_STOP#