W311_05 Datasheet, PDF (11/19 Pages) Cypress Semiconductor – FTG for VIA™ Pro-266 DDR Chipset

W311
Table 5. Additional Frequency Selections through Serial Data Interface Data Bytes
Input Conditions
Output Frequency
FS4
FS3
FS2
FS1
FS0
SEL4 SEL3 SEL2 SEL1 SEL0
CPU
3V66
PCI
0
0
0
0
0
200.0
66.6
33.3
0
0
0
0
1
190.0
76.0
38.0
0
0
0
1
0
180.0
72.0
36.0
0
0
0
1
1
170.0
68.0
34.0
0
0
1
0
0
166.0
66.4
33.2
0
0
1
0
1
160.0
64.0
32.0
0
0
1
1
0
150.0
75.0
37.5
0
0
1
1
1
145.0
72.5
36.3
0
1
0
0
0
140.0
70.0
35.0
0
1
0
0
1
136.0
68.0
34.0
0
1
0
1
0
130.0
65.0
32.5
0
1
0
1
1
124.0
62.0
31.0
0
1
1
0
0
66.6
66.6
33.3
0
1
1
0
1
100.0
66.6
33.3
0
1
1
1
0
118.0
78.7
39.3
0
1
1
1
1
133.3
66.6
33.3
1
0
0
0
0
66.8
66.8
33.4
1
0
0
0
1
100.2
66.8
33.4
1
0
0
1
0
115.0
76.7
38.3
1
0
0
1
1
133.6
66.8
33.4
1
0
1
0
0
66.8
66.8
33.4
1
0
1
0
1
100.2
66.8
33.4
1
0
1
1
0
110.0
73.3
36.7
1
0
1
1
1
133.6
66.8
33.4
1
1
0
0
0
105.0
70.0
35.0
1
1
0
0
1
90.0
60.0
30.0
1
1
0
1
0
85.0
56.7
28.3
1
1
0
1
1
78.0
78.0
39.0
1
1
1
0
0
66.6
66.6
33.3
1
1
1
0
1
100.0
66.6
33.3
1
1
1
1
0
75.0
75.0
37.5
1
1
1
1
1
133.3
66.6
33.3
PLL Gear
Constants
(G)
48.00741
48.00741
48.00741
48.00741
48.00741
48.00741
48.00741
48.00741
48.00741
48.00741
48.00741
48.00741
48.00741
48.00741
48.00741
48.00741
48.00741
48.00741
48.00741
48.00741
48.00741
48.00741
48.00741
48.00741
48.00741
48.00741
48.00741
48.00741
48.00741
48.00741
48.00741
48.00741
Programmable Output Frequency, Watchdog Timer and
Recovery Output Frequency Functional Description
The Programmable Output Frequency feature allows users to
generate any CPU output frequency from the range of 50 MHz
to 248 MHz. Cypress offers the most dynamic and the simplest
programming interface for system developers to utilize this
feature in their platforms.
The Watchdog Timer and Recovery Output Frequency
features allow users to implement a recovery mechanism
when the system hangs or getting unstable. System BIOS or
other control software can enable the Watchdog timer before
they attempt to make a frequency change. If the system hangs
and a Watchdog timer time-out occurs, a system reset will be
generated and a recovery frequency will be activated.
All of the related registers are summarized inTable 7.
Document #: 38-07703 Rev. **
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