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W164

Model	W164
Description	Spread Spectrum Desktop/Notebook System Frequency Generator
PDF file	Total 11 pages (File size: 140K)
Chip Manufacturer	CYPRESS

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W164

Writing Data Bytes

Each bit in the data bytes controls a particular device function

except for the “reserved” bits, which must be written as a logic

0. Bits are written MSB (most significant bit) first, which is bit

Table 4

gives the bit formats for registers located in Data

Bytes 3–6.

Table 4. Data Bytes 3–6 Serial Configuration Map

Affected Pin

Bit(s)

Pin No.

Pin Name

Control Function

SEL_3

SEL_2

SEL_1

SEL_0

Frequency Table

Selection

(Reserved)

Bit 1

Bit 0

Refer to

Table 5

Refer to

Table 5

Refer to

Table 5

Frequency Controlled

by external SEL100/

66# pin

Table 1

Function (See

Table 6

for function details)

Normal Operation

Test Mode

Spread Spectrum on

All Outputs Three-stated

Low

Active

Frequency Controlled

by BYT3 SEL_(3:0)

Table 5

Data Byte 3

Bit Control

Default

Table 5

details additional frequency selections that are avail-

able through the serial data interface.

Table 6

details the select functions for Byte 3, bits 1 and 0.

1–0

Data Byte 4

Data Byte 5

Data Byte 6

PCI_F

PCI6

PCI5

PCI4

PCI3

PCI2

PCI1

IOAPIC

REF2X

Clock Output Disable

(Reserved)

Clock Output Disable

(Reserved)

Clock Output Disable

(Reserved)

Clock Output Disable

[1]

24/48MHz

CPU1

CPU0

(Reserved)

Clock output Disable

(Reserved)

Clock Output Disable

(Reserved)

Clock Output Disable

Note:

1. Both Bits 0 and 1 of Byte 6 in

Table 4

must be programmed as the same value.

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