C9630 Datasheet, PDF (3/18 Pages) Cypress Semiconductor – PC133 Clock Generator for SiS630/Pentium III & SiS540/Socket7 Applications

APPROVED PRODUCT
C9630
PC133 Clock Generator for SiS630/Pentium^®III & SiS540/Socket7 Applications
Device Clock Phase Relationships
Condition 1: CPU Frequency = SDRAM Frequency
Applicable to the follow ing selections: S(4:0) = 00001, 00111, 01000, 01001, 01011, 01101, 01111, 10001, 10111,11010, 11011, 11100, 11101, 11110, 11111
Internal VCO
SDRAM
CPU
or
to CPU
to SDRAM
TSkew 3
Internal VCO
SDRAM
CPU
or
to CPU
to SDRAM
Condition 2: CPU Frequency = 1.5 X SDRAM Frequency or SDRAM Frequency = 1.5 X CPU Frequency
Applicable to the follow ing selections: S(4:0) = 00000, 00010, 00110, 01010, 10000, 10010, 10101
TSkew 3
Internal VCO
SDRAM
CPU
or
to CPU
to SDRAM
Condition 3: CPU Frequency = 1.3 X SDRAM Frequency or SDRAM Frequency = 1.3 X CPU Frequency
Applicable to the follow ing selections: S(4:0) = 00011, 00101, 01100, 01110, 10011, 10100, 10110, 11000, 11001
TSkew 3
Internal VCO
SDRAM
CPU
Condition 4: SDRAM Frequency = 2 X CPU Frequency
Applicable to the follow ing selection: S(4:0) = 00100
TSkew 3
Fig.3
Frequency Smooth Switching Groups
Group
S(4:0)
2
00000, 00011, 00110, 01010, 10000, 10101
3
00100, 00101, 01000, 01001, 01011, 01100, 01110, 01111, 10011, 10100, 10110, 11000, 11001
Table 2
Table 2 above describes 3 different groups of frequencies. Within the same group, frequency may be switched through
SMBus byte 0 without causing any glitching or clock discontinuity at the CPU(0:2) outputs, therefore allowing frequency
smooth switching of the clock.
Switching frequency from one group to another is permitted but will cause the CPU(0:2) clocks to jump immediately to
the next frequency. (non smooth switching.).
Cypress Semiconductor Corporation
525 Los Coches St.
Milpitas, CA 95035. Tel: [phone], Fax: [phone]
http://www.cypress.com
Document#: 38-07035 Rev. **
05/02/2001
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