W144 Datasheet, PDF (8/14 Pages) Cypress Semiconductor – 440BX AGPset Spread Spectrum Frequency Synthesizer

PRELIMINARY
W144
Table 6. Additional Frequency Selections through Serial Data Interface Data Bytes
Bit 2
SEL_3
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
Input Conditions
Data Byte 0, Bit 3 = 1
Bit 6
SEL_2
Bit 5
SEL_1
1
1
1
1
1
0
1
0
0
1
0
1
0
0
0
0
1
1
1
1
1
0
1
0
0
1
0
1
0
0
0
0
Bit 4
SEL_0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
Output Frequency
CPU, SDRAM Clocks
(MHz)
133.3
124
150
140
105
110
115
120
100
133
112
103
66.8
83.3
75
124
PCI Clocks
(MHz)
33.3 (CPU/4)
31 (CPU/4)
37.5 (CPU/4)
35 (CPU/4)
35 (CPU/3)
36.7 (CPU/3)
39.3 (CPU/3)
40 (CPU/3)
33.3 (CPU/3)
44.3 (CPU/3)
37.3 (CPU/3)
34.3 (CPU/3)
33.4 (CPU/2)
41.7 (CPU/2)
37.5 (CPU/2)
41.3 (CPU/3)
Table 7. Select Function for Data Byte 0, Bits 0:1
Input Conditions
Function
Data Byte 0
Bit 1
Bit 0
CPU_F,
CPU1
Normal Operation
0
0
Note 1
Spread Spectrum
1
0
±0.5%
Three-state
1
1
Hi-Z
Note:
2. CPU and PCI frequency selections are listed in Table 2 and Table 6.
Output Conditions
PCI_F,
PCI1:5
Note 1
±0.5%
Hi-Z
REF0:1,
IOAPIC
14.318 MHz
14.318 MHz
Hi-Z
48MHZ
48 MHz
48 MHz
Hi-Z
24MHZ
24 MHz
24 MHz
Hi-Z
8