PRELIMINARY
W212
Frequency Timing Generator for ALI 1641
CPU to PCI Offset: ........................ 1.0 to 3.0 ns (CPU leads)
Features
AGP Outputs Skew:.....................................................250 ps
• Maximized EMI Suppression using Cypress’s Spread
Spectrum technology
• I C™ interface
• Two copies of CPU Output
• One copy of IOAPIC Output
SDRAM Outputs Skew: ...............................................250 ps
PCI Outputs Skew: ......................................................500 ps
AGP to PCI Skew: .......................................................... TBD
2
Table 1. Pin Selectable Frequency (Center Spread)
• Six copies of PCI Output
• Two copies of AGP Output
Input Address
CPU
(MHz)
SDRAM
(MHz)
AGP
(MHz)
PCI
(MHz)
APIC
(MHz)
FS3 FS2 FS1 FS0
• One copy of selectable 48-MHz or 24-MHz Output
• Thirteen copies of SDRAM Output
• Two buffered copy of 14.318-MHz reference clock
• Mode input pin selects optional power management in-
put control pins (reconfigures pins 19, 20, 21 and 22)
• Smooth frequency transition upon frequency
reselection
• Available in 48-pin SSOP (300 mils)
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
66.8
100.2
66.8
100.2
100.2
66.8
66.8
66.8
66.8
66.8
66.8
66.8
66.8
66.6
63.3
63.3
70.0
73.3
61.0
61.0
70.0
73.0
33.4
33.4
33.4
33.4
33.4
33.4
33.4
33.4
31.6
31.6
35.0
36.6
30.5
30.5
35.0
36.5
16.7
16.7
16.7
16.7
16.7
16.7
16.7
16.7
15.8
15.8
17.5
18.3
15.3
15.3
17.5
18.3
133.6
66.8
100.2
133.6
133.6
66.8
100.2
100.2
133.6
95.0
133.6
95.0
Key Specifications
95.0
126.6
140.0
110.0
122.0
91.5
Supply Voltages: ....................................... V
V
= 3.3V±5%
= 2.5V±5%
DDQ3
DDQ2
105.0
110.0
122.0
122.0
140.0
146.0
CPU Cycle to Cycle Jitter: .......................................... 250 ps
CPU Outputs Skew:.................................................... 175 ps
CPU to AGP Offset: .................................................. <500 ps
CPU to SDRAM Offset:............................................. <500 ps
105.0
146.0
Pin Configuration[1]
Block Diagram
VDDQ3
PLL REF
REF0/FS2
REF1/FS1
X1
X2
PWD
XTAL
PLL1
REF0/FS2*
VDDQ2
IOAPIC
VDDQ2
CPU_F
CPU
*FS1/REF1
1
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
VDDQ3
2
X1
X2
GND
GND
3
VDDQ2
CPU_F
4
5
PWD
6
7
8
9
CPU
DIV
^FS3/AGP0
GND
STOP/
PWD
CPU
AGP1
GND
VDDQ3
SDRAM0
SDRAM1
SDRAM2
VDDQ3
SDRAM3
SDRAM4
SDRAM5
GND
VDDQ3
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
VDDQ3
*FS0/PCI_F
PCI1
9
(AGP_STOP#)
(CPU_STOP#)
(PCI_STOP#)
(PWR_DWN#)
SDR
DIV
SDRAM(_0:8)
PCI2
GND
PWD
Control
Unit
PCI3
PCI4
PCI5
SDRAM9 (AGP_STOP#)
SDRAM10(PWR_DWN#)
SDRAM11 (PCI_STOP#)
SDRAM12 (CPU_STOP#)
SDRAM6
SDRAM7
SDRAM8
VDDQ3
GND
48_24MHz/Mode*
VDDQ3
SDATA
(FS0:3)
Mode
VDDQ3
*(CPU_STOP#)SDRAM12
*(PCI_STOP#)SDRAM11
*(PWR_DWN#)SDRAM10
*(AGP_STOP#))SDRAM9
GND
VDDQ3
AGP1
SDATA
SCLK
AGP
DIV
2
STOP/
PWD
I C
SCLOCK
AGP0/FS3
÷2
PCI_F/FS0
PCI(1:5)
PWD
5
Note:
STOP
PWD
1. Signal names with (*) denotes pins have internal 140K pull-up resis-
tor, though not relied upon for pulling to VDDQ3. Signal names with
parentheses denotes function is selectable by MODE pin strapping.
2. Signal names with (^) denotes pins have internal 55K pull-down re-
sistor, though not relied upon for pulling to VDDQ3. Signal names with
VDDQ2
IOAPIC
VDDQ3
÷2
parentheses denotes function is selectable by MODE pin strapping.
PWD
÷1/÷2
PLL2
48_24MHz/Mode
I2C is a trademark of Philips Corporation.
Cypress Semiconductor Corporation
•
3901 North First Street
•
San Jose
•
CA 95134
•
408-943-2600
April 5, 2000 rev. **