ICS950202 Datasheet, PDF (5/19 Pages) Integrated Circuit Systems – Programmable Timing Control HubTM for P4TM

Integrated
Circuit
Systems, Inc.
ICS950202
Byte 0: Functionality and frequency select register (Default=0)
Bit
Description
Bit
(2,7:4)
Bit 3
Bit 1
Bit 0
Bit2 Bit7 Bit6 Bit5 Bit4 _{CPUCLK 3V66 PCICLK}
FS4 FS3 FS2 FS1 FS0 ^{MHz MHz MHz}
Spread %
0 0 0 0 0 100.90 67.27 33.63 +/-0.35% center spread
0 0 0 0 1 100.00 66.67 33.33 0 to -0.6% down spread
0 0 0 1 0 103.00 68.67 34.33 +/-0.35% center spread
0 0 0 1 1 105.00 70.00 35.00 +/-0.35% center spread
0 0 1 0 0 107.00 71.33 35.67 +/-0.35% center spread
0 0 1 0 1 109.00 72.67 36.33 +/-0.35% center spread
0 0 1 1 0 111.00 74.00 37.00 +/-0.35% center spread
0 0 1 1 1 114.00 76.00 38.00 +/-0.35% center spread
0 1 0 0 0 117.00 78.00 39.00 +/-0.35% center spread
0 1 0 0 1 120.00 80.00 40.00 +/-0.35% center spread
0 1 0 1 0 127.00 84.67 42.33 +/-0.35% center spread
0 1 0 1 1 130.00 86.67 43.33 +/-0.35% center spread
0 1 1 0 0 133.33 88.89 44.44 +/-0.35% center spread
0 1 1 0 1 170.00 56.67 28.33 +/-0.35% center spread
0 1 1 1 0 180.00 60.00 30.00 +/-0.35% center spread
0 1 1 1 1 190.00 63.33 31.67 +/-0.35% center spread
1 0 0 0 0 133.90 66.95 33.48 +/-0.35% center spread
1 0 0 0 1 133.33 66.67 33.33 0 to -0.6% down spread
1 0 0 1 0 120.00 60.00 30.00 +/-0.35% center spread
1 0 0 1 1 125.00 62.50 31.25 +/-0.35% center spread
1 0 1 0 0 134.90 67.45 33.73 +/-0.35% center spread
1 0 1 0 1 137.00 68.50 34.25 +/-0.35% center spread
1 0 1 1 0 139.00 69.50 34.75 +/-0.35% center spread
1 0 1 1 1 141.00 70.50 35.25 +/-0.35% center spread
1 1 0 0 0 143.00 71.50 35.75 +/-0.35% center spread
1 1 0 0 1 145.00 72.50 36.25 +/-0.35% center spread
1 1 0 1 0 150.00 75.00 37.5 +/-0.35% center spread
1 1 0 1 1 155.00 77.50 38.75 +/-0.35% center spread
1 1 1 0 0 160.00 80.00 40.00 +/-0.35% center spread
1 1 1 0 1 170.00 85.00 42.50 +/-0.35% center spread
1 1 1 1 0 66.67 66.67 33.34 0 to -0.6% down spread
1 1 1 1 1 200.00 66.67 33.33 0 to -0.6% down spread
0 - Frequency is selected by hardware select, latched inputs
1 - Frequency is selected by Bit 2,7:4
0 - Normal
1 - Spread spectrum enable
0 - Watch dog safe frequency will be selected by latch inputs
1 - Watch dog safe frequency will be programmed by Byte 10 bit (4:0)
PWD
Note 1
0
1
0
Notes:
1. Default at power-up will be for latched logic inputs to define frequency, as displayed by Bit 3.
0461L—05/28/03
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