ICS9148-75 Datasheet, PDF (6/17 Pages) Integrated Circuit Systems – Frequency Generator & Integrated Buffers for Mother Boards

ICS9148 - 75
Preliminary Product Preview
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 - ±0.6% Spread Spectrum Modulation
Bit (2, 6:4) CPU CLKs PCI CLKs AGP CLKs
1111
105
35
70
1110
110
36.67
73.34
1101
115
38.33
76.66
1100
120
40
80
1011
125
41.66
83.32
1010
130
43.33
86.66
1001
135
45
90
1000
140
46.67
93.44
0111
100
33.3
66.6
0110
95.25
31.75
63.5
0101
83.3
33.3
66.6
0100
75
30
60
0011
75
37.5
75
0010
68.5
34.25
68.5
0001
66.8
33.4
66.8
0000
60
30
60
0 - Frequency is selected by hardware select,
Latched Inputs
1 - Frequency is selected by Bit 6:4 (above)
0 - Normal
1 - Spread Spectrum Enabled (center spread)
0 - Running
1- Tristate all outputs
PWD
0
Note1
0
0
0
Note 1: Default at power-up will be for latched logic inputs to define frequency;
Bits 2, 6:4 are default to 000
Note: PWD = Power-Up Default
I²C is a trademark of Philips Corporation
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