CY28325 Cypress Semiconductor Corp., CY28325 Datasheet - Page 12

• Manufacturer Part Number: CY28325
• Description: FTG For Via Pentium 4 Chipsets
• Manufacturer: Cypress Semiconductor Corp.

Table 4. Frequency Selection Table
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.
Document #: 38-07119 Rev. **
SEL4
FS4
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
SEL3
FS3
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
Input Conditions
SEL2
FS2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
SEL1
FS1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
PRELIMINARY
SEL0
FS0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
102.0
105.0
108.0
114.0
117.0
120.0
123.0
126.0
130.0
136.0
140.0
144.0
148.0
152.0
156.0
160.0
164.0
166.6
170.0
175.0
180.0
185.0
190.0
100.2
133.6
200.4
100.0
200.0
133.3
111.0
CPU
66.8
66.6
The Watchdog Timer and Recovery Output Frequency fea-
tures 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 the
related registers are summarized in the following table.
Output Frequency
AGP
68.0
70.0
72.0
74.0
76.0
78.0
80.0
82.0
63.0
65.0
68.0
70.0
72.0
74.0
76.0
78.0
80.0
82.0
66.6
68.0
70.0
72.0
74.0
76.0
66.8
66.8
66.8
66.8
66.6
66.6
66.6
66.6
34.0
35.0
36.0
37.0
38.0
39.0
40.0
41.0
31.5
32.5
34.0
35.0
36.0
37.0
38.0
39.0
40.0
41.0
33.3
34.0
35.0
36.0
37.0
38.0
33.4
33.4
33.4
33.4
33.3
33.3
33.3
33.3
PCI
APIC
17.0
17.5
18.0
18.5
19.0
19.5
20.0
20.5
18.0
18.5
17.0
17.5
18.0
18.5
19.0
19.5
20.0
20.5
16.7
17.0
17.5
18.0
18.5
19.0
16.7
16.7
16.7
16.7
16.5
16.5
16.5
16.5
CY28325-2
Constants
Page 12 of 19
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