ICS9248-95 Datasheet, PDF (5/16 Pages) Integrated Circuit Systems – Frequency Generator & Integrated Buffers for PENTIUM/ProTM

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
1 - ±0.5% Spread Spectrum Modulation
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
80.00
40.00
0111
75.00
37.50
1000
100.00
33.33
1001
95.19
31.73
1010
83.31
27.77
1011
80.00
32.33
1100
90.00
30.00
1101
70.00
35.00
1110
66.82
33.41
1111
60.00
30.00
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
Note 1. Default at Power-up will be for latched logic inputs to define frequency.
Bit [2, 6:4] are default to 0000.
Note: PWD = Power-Up Default
ICS9248 - 95
I²C is a trademark of Philips Corporation
310D—04/12/05
5