ICS9248-162 Datasheet, PDF (3/16 Pages) Integrated Circuit Systems – Frequency Generator & Integrated Buffers for PENTIUM/ProTM & K6

ICS9248 - 162
Functionality
V_DD = 3.3V±5%, V_DDL= 2.5V±5% or 3.3±5%, TA=0 to 70°C
Crystal (X1, X2) = 14.31818MHz
FS3 FS2 FS1 FS0
0
0
0
0
0
0
0
1
0
0
1
0
0
0
1
1
0
1
0
0
0
1
0
1
0
1
1
0
0
1
1
1
1
0
0
0
1
0
0
1
1
0
1
0
1
0
1
1
1
1
0
0
1
1
0
1
1
1
1
0
1
1
1
1
CPU
(MHz)
124.00
120.00
114.99
109.99
105.00
83.31
137.00
75.00
100.00
95.00
97.00
133.33
90.00
96.22
66.82
91.5
PCI
(MHz)
41.33
40.00
38.33
36.66
35.00
41.65
34.25
37.50
33.33
31.67
32.33
33.33
30.00
32.07
33.41
30.5
Serial Configuration Command Bitmap
Byte0: Functionality and Frequency Select Register (default = 0)
Bit
Bit 7
Bit
[2, 6:4]
Bit 3
Bit 1
Bit 0
Description
0 - ±0.25% Spread Spectrum Modulation, Center Spread
1 - 0 to -0.5% Down Spread
Bit [2, 6:4]
CPUCLK
(MHz)
PCICLK
(MHz)
0000
124.00
41.33
0001
120.00
40.00
0010
114.99
38.33
0011
109.99
36.66
0100
105.00
35.00
0101
83.31
41.65
0110
137.00
34.25
0111
75.00
37.50
1000
100.00
33.33
1001
95.00
31.67
1010
97.00
32.33
1011
133.33
33.33
1100
90.00
30.00
1101
96.22
32.07
1110
66.82
33.41
1111
91.5
30.5
0 - Frequency is selected by hardware select, latched inputs
1 - Frequency is selected by Bit (2, 6:4)
0 - Normal
1 - Spread Spectrum Enabled
0 - Running
1- Tristate all outputs
PWD
1
Note1
0
1
0
Notes:
1, Default at Power-up will be for latched
logic inputs to define frequency.
Bit (2, 6:4) are default to 0010.
2, PWD = Power-Up Default
3, When disabling spread spectrum bit7
needs to be set to 0 to maintain nominal
frequency.
3