ICS950508 Datasheet, PDF (4/19 Pages) Integrated Circuit Systems – Programmable Timing Control HubTM for PII/IIITTM

Integrated
Circuit
Systems, Inc.
ICS950508
Byte 0: Functionality and frequency select register (Default=0)
Bit
Description
PWD
Bit2 Bit7 Bit6 Bit5 Bit4 _{CPUCLK SDRAM 3V66 PCICLK IOAPIC}
FS4 FS3 FS2 FS1 FS0 ^MHz
MHz MHz
MHz
MHz
Bit
(2,7:4)
Bit 3
Bit 1
Bit 0
0 0 0 0 0 66.43 99.65 66.43 33.21
0 0 0 0 1 60.00 90.00 60.00 30.00
0 0 0 1 0 66.80 100.20 66.80 33.40
0 0 0 1 1 68.33 102.50 68.33 34.17
0 0 1 0 0 70.00 105.00 70.00 35.00
0 0 1 0 1 75.00 112.50 75.00 37.50
0 0 1 1 0 80.00 120.00 80.00 40.00
0 0 1 1 1 83.00 124.50 83.00 41.50
0 1 0 0 0 99.65 99.65 66.43 33.21
0 1 0 0 1 90.00 90.00 60.00 30.00
0 1 0 1 0 100.23 100.23 66.84 33.41
0 1 0 1 1 103.00 103.00 68.67 34.33
0 1 1 0 0 105.00 105.00 70.00 35.00
0 1 1 0 1 110.00 110.00 73.33 36.67
0 1 1 1 0 115.00 115.00 76.67 38.33
0 1 1 1 1 200.00 200.00 133.33 66.66
1 0 0 0 0 132.86 132.86 66.43 33.21
1 0 0 0 1 166.67 166.67 83.34 41.67
1 0 0 1 0 133.64 133.64 66.82 33.41
1 0 0 1 1 137.00 137.00 68.50 34.25
1 0 1 0 0 140.00 140.00 70.00 35.00
1 0 1 0 1 145.00 145.00 72.50 36.25
1 0 1 1 0 150.00 150.00 75.00 37.50
1 0 1 1 1 160.00 160.00 80.00 40.00
1 1 0 0 0 132.86 99.65 66.93 33.21
1 1 0 0 1 166.67 125.00 83.34 41.67
1 1 0 1 0 133.64 100.23 66.82 33.41
1 1 0 1 1 137.00 102.75 68.50 34.25
1 1 1 0 0 140.00 105.00 70.00 35.00
1 1 1 0 1 145.00 108.75 72.50 36.25
1 1 1 1 0 150.00 112.50 75.00 37.50
1 1 1 1 1 160.00 120.00 80.00 40.00
0-Frequency is selected by hardware select, latched inputs
1- Frequency is selected by Bit 2,7:4
0- Normal
1- Spread spectrum enable ± 0.35% Center Spread
0- Running
1- Tristate all outputs
16.61
15.00
16.70
17.08
17.50
18.75
20.00
20.75
16.61
15.00
16.70
17.17
17.50
18.33
19.17
33.33
16.61
20.83
16.70
17.13
17.50
18.13
18.75
20.00
16.61
20.83
16.7
17.13
17.50
18.13
18.75
20.00
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.
0470E—04/06/05
4