CY28405
MODE Select
Frequency Select Pins
The hardware strapping MODE input pin can be used to select
the functionality of the RESET#/PD# pin. The default (internal
pull up) configuration is for this pin to function as a RESET#
Watchdog output. When pulled LOW during device power-up,
the RESET#/PD# pin will be configured to function as a Power
Down input pin.
Host clock frequency selection is achieved by applying the
appropriate logic levels to FS_A through FS_E inputs prior to
VTT_PWRGD# assertion (as seen by the clock synthesizer).
Upon VTT_PWRGD# being sampled low by the clock chip
(indicating processor VTT voltage is stable), the clock chip
samples the FS_A through FS_E input values. For all logic
levels of FS_A through FS_E, VTT_PWRGD# employs a
one-shot functionality in that once
a valid low on
VTT_PWRGD# has been sampled, all further VTT_PWRGD#
and FS_A through FS_E transitions will be ignored.
Table 1. Frequency Selection Table
Input Conditions
Output Frequency
PLL Gear
Constants
FS_E
FS_D
FS_C
FS_B
FS_A
FSEL_4 FSEL_3 FSEL_2 FSEL_1 FSEL_0
CPU
100.7
3V66
67.1
PCI
33.6
33.4
36.0
33.7
VCO Freq.
805.6
(G)
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
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
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
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
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
24004009.32
24004009.32
24004009.32
24004009.32
Reserved
100.2
66.8
801.6
108.0
72.0
864.0
101.2
67.5
809.6
Reserved
Reserved
Reserved
Reserved
125.7
Reserved
Reserved
Reserved
Reserved
62.9
Reserved Reserved
Reserved Reserved
Reserved Reserved
Reserved Reserved
Reserved
Reserved
Reserved
31.4
32.6
33.4
33.6
33.6
37.0
754.2
781.6
801.6
805.2
807.0
888.0
32005345.76
32005345.76
32005345.76
32005345.76
32005345.76
32005345.76
Reserved
130.3
65.1
133.6
66.8
134.2
67.1
134.5
67.3
148.0
74.0
Reserved
Reserved
Reserved
Reserved
167.4
Reserved
Reserved
Reserved
Reserved
55.8
Reserved Reserved
Reserved Reserved
Reserved Reserved
Reserved Reserved
Reserved
Reserved
Reserved
27.9
28.3
29.2
30.0
30.8
31.7
33.6
33.5
33.5
669.6
680.0
700.0
720.0
740.0
760.0
807.2
803.4
803.6
48008018.65
48008018.65
48008018.65
48008018.65
48008018.65
48008018.65
24004009.32
32005345.76
48008018.65
Reserved
170.0
56.7
175.0
58.3
180.0
60.0
185.0
61.7
190.0
63.3
100.9
67.3
133.9
67.0
200.9
67.0
Reserved
100.0
Reserved
66.7
Reserved Reserved
33.3
33.3
33.3
800.0
800.0
800.0
24004009.32
32005345.76
48008018.65
Reserved
133.3
66.7
200.0
66.7
Reserved
Reserved
Reserved Reserved
Rev 1.0,November 20, 2006
Page 3 of 18
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