ICS950508 Datasheet, PDF (8/19 Pages) Integrated Circuit Systems – Programmable Timing Control HubTM for PII/IIITTM

Integrated
Circuit
Systems, Inc.
Byte 13: Spread Spectrum Control Register
Bit
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Name
SS 7
SS 6
SS 5
SS 4
SS 3
SS 2
SS 1
SS 0
PWD
Description
X _{The Spread Spectrum (12:0) bit will}
X program the spread precentage. Spread
X ^{precent needs to be calculated based on}
X
X
the VCO frequency, spreading profile,
spreading amount and spread frequency. It
is recommended to use the ICS spread
X _{programming guide for spread}
X programming. Default power on is latched
X ^{FS divider.}
Byte 14: Spread Spectrum Control Register
Bit
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Name
Reserved
Reserved
Reserved
SS 12
SS 11
SS 10
SS 9
SS 8
PWD
Description
X Reserved
X Reserved
X Reserved
X Spread Spectrum Bit 12
X Spread Spectrum Bit 11
X Spread Spectrum Bit 10
X Spread Spectrum Bit 9
X Spread Spectrum Bit 8
Byte 15: Output Divider Control Register
Bit
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Name
SD Div 3
SD Div 2
SD Div 1
SD Div 0
CPU Div 3
CPU Div 2
CPU Div 1
CPU Div 0
PWD
X
X
X
X
X
X
X
X
Description
SDRAM clock divider ratio can be
configured via these 4 bits individually.
For divider selection table refer to
Table 1. Default at power up is latched
FS divider.
CPU clock divider ratio can be
configured via these 4 bits individually.
For divider selection table refer to
Table 1. Default at power up is latched
FS divider.
Byte 16: Output Divider Control Register
Bit
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Name
PCI Div 3
PCI Div 2
PCI Div 1
PCI Div 0
AGP Div 3
AGP Div 2
AGP Div 1
AGP Div 0
PWD
X
X
X
X
X
X
X
X
Description
PCI clock divider ratio can be
configured via these 4 bits individually.
For divider selection table refer to
Table 2. Default at power up is latched
FS divider.
AGP clock divider ratio can be
configured via these 4 bits individually.
For divider selection table refer to
Table 1. Default at power up is latched
FS divider.
0470E—04/06/05
8
ICS950508