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W311
Document #: 38-07703 Rev. **
Page 11 of 19
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.
Table 5. Additional Frequency Selections through Serial Data Interface Data Bytes
Input Conditions
Output Frequency
PLL Gear
Constants
(G)
FS4
FS3
FS2
FS1
FS0
CPU
3V66
PCI
SEL4
SEL3
SEL2
SEL1
SEL0
0
0
0
0
0
200.0
66.6
33.3
48.00741
0
0
0
0
1
190.0
76.0
38.0
48.00741
0
0
0
1
0
180.0
72.0
36.0
48.00741
0
0
0
1
1
170.0
68.0
34.0
48.00741
0
0
1
0
0
166.0
66.4
33.2
48.00741
0
0
1
0
1
160.0
64.0
32.0
48.00741
0
0
1
1
0
150.0
75.0
37.5
48.00741
0
0
1
1
1
145.0
72.5
36.3
48.00741
0
1
0
0
0
140.0
70.0
35.0
48.00741
0
1
0
0
1
136.0
68.0
34.0
48.00741
0
1
0
1
0
130.0
65.0
32.5
48.00741
0
1
0
1
1
124.0
62.0
31.0
48.00741
0
1
1
0
0
66.6
66.6
33.3
48.00741
0
1
1
0
1
100.0
66.6
33.3
48.00741
0
1
1
1
0
118.0
78.7
39.3
48.00741
0
1
1
1
1
133.3
66.6
33.3
48.00741
1
0
0
0
0
66.8
66.8
33.4
48.00741
1
0
0
0
1
100.2
66.8
33.4
48.00741
1
0
0
1
0
115.0
76.7
38.3
48.00741
1
0
0
1
1
133.6
66.8
33.4
48.00741
1
0
1
0
0
66.8
66.8
33.4
48.00741
1
0
1
0
1
100.2
66.8
33.4
48.00741
1
0
1
1
0
110.0
73.3
36.7
48.00741
1
0
1
1
1
133.6
66.8
33.4
48.00741
1
1
0
0
0
105.0
70.0
35.0
48.00741
1
1
0
0
1
90.0
60.0
30.0
48.00741
1
1
0
1
0
85.0
56.7
28.3
48.00741
1
1
0
1
1
78.0
78.0
39.0
48.00741
1
1
1
0
0
66.6
66.6
33.3
48.00741
1
1
1
0
1
100.0
66.6
33.3
48.00741
1
1
1
1
0
75.0
75.0
37.5
48.00741
1
1
1
1
1
133.3
66.6
33.3
48.00741
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