W164G Cypress Semiconductor Corp., W164G Datasheet - Page 5

• Manufacturer Part Number: W164G
• Description: Spread Spectrum Desktop / Notebook System Frequency Generator
• Manufacturer: Cypress Semiconductor Corp.

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
7. Table 4 gives the bit formats for registers located in Data
Bytes 3–6.
Table 4. Data Bytes 3–6 Serial Configuration Map
Note:
Document #: 38-07169 Rev. *A
1.
Data Byte 3
Data Byte 4
Data Byte 5
Data Byte 6
Bit(s)
1–0
Both Bits 0 and 1 of Byte 6 in Table 4 must be programmed as the same value.
7
6
5
4
3
2
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
Pin No.
14
21
22
11
10
24
27
27
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
4
8
7
6
5
-
Affected Pin
Pin Name
24/48MHz
IOAPIC
REF2X
REF2X
PCI_F
CPU1
CPU0
PCI6
PCI5
PCI4
PCI3
PCI2
PCI1
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
SEL_3
SEL_2
SEL_1
SEL_0
Frequency Table
Selection
(Reserved)
(Reserved)
Clock output Disable
(Reserved)
(Reserved)
(Reserved)
Clock Output Disable
(Reserved)
Clock Output Disable
Clock Output Disable
Clock Output Disable
Clock Output Disable
(Reserved)
Clock Output Disable
Clock Output Disable
Clock Output Disable
Clock Output Disable
(Reserved)
(Reserved)
Clock Output Disable
(Reserved)
(Reserved)
(Reserved)
Clock Output Disable
Clock Output Disable
Bit 1
Control Function
0
0
1
1
Bit 0
0
1
0
1
Function (See Table 6 for function details)
Normal Operation
Test Mode
Spread Spectrum on
All Outputs Three-stated
Frequency Controlled
by external SEL100/
66# pin Table 1
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.
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
--
--
--
--
--
--
--
--
--
--
--
--
--
0
Refer to Table 5
Refer to Table 5
Refer to Table 5
Bit Control
Frequency Controlled
by BYT3 SEL_(3:0)
Table 5
Active
Active
Active
Active
Active
Active
Active
Active
Active
Active
Active
Active
Active
--
--
--
--
--
--
--
--
--
--
--
--
--
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W164
0
0
0
0
0
0
0
1
0
0
0
1
0
1
1
1
1
0
1
1
1
1
0
0
1
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0
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