ICS94209 Datasheet, PDF (6/19 Pages) Integrated Circuit Systems – Programmable Frequency Generator & Integrated Buffers for Pentium III Processor

ICS94209
Byte 11: VCO Frequency Control Register
Bit PWD
Description
Bit 7 X VCO Divider Bit0
Bit 6 X REF Divider Bit6
Bit 5 X REF Divider Bit5
Bit 4 X REF Divider Bit4
Bit 3 X REF Divider Bit3
Bit 2 X REF Divider Bit2
Bit 1 X REF Divider Bit1
Bit 0 X REF Divider Bit0
Note: The decimal representation of these 7 bits (Byte 11
[6:0]) + 2 is equal to the REF divider value .
Notes:
1. PWD = Power on Default
Byte 13: Spread Sectrum Control Register
Bit
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PWD
X
X
X
X
X
X
X
X
Description
Spread Spectrum Bit7
Spread Spectrum Bit6
Spread Spectrum Bit5
Spread Spectrum Bit4
Spread Spectrum Bit3
Spread Spectrum Bit2
Spread Spectrum Bit1
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
1
0
0
1
1
1
1
0
Description
SDRAM 12 Skew Control
SDRAM (11:0) Skew Control
CPUCLK2 Skew Control
CPUCLK (1:0) Skew Control
Byte 12: VCO Frequency Control Register
Bit
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PWD
X
X
X
X
X
X
X
X
Description
VCO Divider Bit8
VCO Divider Bit7
VCO Divider Bit6
VCO Divider Bit5
VCO Divider Bit4
VCO Divider Bit3
VCO Divider Bit2
VCO Divider Bit1
Note: The decimal representation of these 9 bits (Byte 12
bit [7:0] & Byte 11 bit [7] ) + 8 is equal to the VCO divider
value. For example if VCO divider value of 36 is desired,
user need to program 36 - 8 = 28, namely, 0, 00011100 into
byte 12 bit & byte 11 bit 7.
Byte 14: Spread Sectrum Control Register
Bit
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PWD
X
X
X
X
X
X
X
X
Description
Reserved
Reserved
Reserved
Spread Spectrum Bit12
Spread Spectrum Bit11
Spread Spectrum Bit10
Spread Spectrum Bi 9
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
X
X
X
X
X
X
X
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Description
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