ICS94236 Datasheet, PDF (8/17 Pages) Integrated Circuit Systems – Programmable System Clock Chip for AMD - K7™ processor

ICS94236
Byte 13: Spread Sectrum Control Register
Bit
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PWD
Description
X Spread Spectrum Bit7
X Spread Spectrum Bit6
X Spread Spectrum Bit5
X Spread Spectrum Bit4
X Spread Spectrum Bit3
X Spread Spectrum Bit2
X Spread Spectrum Bit1
X Spread Spectrum Bit0
Note: Please utilize software utility provided by ICS
Application Engineering to configure spread
spectrum. Incorrect spread percentage may cause
system failure.
Byte 15: Output Skew Control
Bit
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PWD
Description
0
0
0
PCI_F Skew Control
0
0
0
0
PCICLK [0:4] Skew Control
0
Byte 14: Spread Sectrum Control Register
Bit
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PWD
Description
X Reserved
X Reserved
X Reserved
X Spread Spectrum Bit12
X Spread Spectrum Bit11
X Spread Spectrum Bit10
X Spread Spectrum Bi 9
X Spread Spectrum Bit8
Note: Please utilize software utility provided by ICS
Application Engineering to configure spread
spectrum. Incorrect spread percentage may cause
system failure.
Byte 16: Output Skew Control
Bit
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PWD
X Reserved
X Reserved
X Reserved
X Reserved
X Reserved
X Reserved
X Reserved
X Reserved
Description
Byte 17: Output Rise/FallTime Select Register
Byte 18: Output Rise/Fall Time Select Register
Bit
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PWD
Description
1 CPUCLKT0
1 CPUCLKC0
X Reserved
0 CPUCLK
1
0
SDRAM_OUT: Slew Rate Control
1
0
SDRAM [0:11] Slew Rate Control
Bit
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PWD
Description
1
0
PCI [0:4]: Slew Rate Control
1
0
PCI_F Slew Rate Control
1
0
48MHz: Slew Rate Control
1
0
24MHz: Slew Rate Control
Notes:
1. PWD = Power on Default
2. The power on default for byte 13-20 depends on the harware (latch inputs FS[0:4]) or I²C (Byte 0 bit [1:7]) setting.
Be sure to read back and re-write the values of these 8 registers when VCO frequency change is desired for the first
pass.
3. If Byte 8 bit 7 is driven to "1" meaning programming is intended, Byte 21-24 will lose their default power up value.
0451A—01/10/03
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