PRELIMINARY
C9926
Low EMI Clock Generator for Intel 133MHz/ 2DIMM Chipset Systems
™
Byte 6: Dial-a-Frequency Register
™
Byte 8: Dial-a-Frequency Register
Bit
7
6
5
4
3
2
1
0
@Pup
Pin#
Description
0
0
0
0
0
0
0
0
-
-
-
-
-
-
-
-
N9, MSB
N8
Bit
7
6
5
4
3
2
1
0
@Pup
Pin#
Description
R7, MSB
R6
R5
R4
R3
R2
R1
R0, LSB
0
0
0
0
0
0
0
0
-
-
-
-
-
-
-
-
N7
N6
N5
N4
N3
N2
™
Byte 7: Dial-a-Frequency Register
Bit
7
6
5
4
3
2
1
0
@Pup
Pin#
Description
N1
N0, LSB
Enable SMBus N values
Enable SMBus R values
Reserved
Reserved
Reserved
Reserved
0
0
0
0
0
0
0
0
-
-
-
-
-
-
-
-
Dial-a-Frequency™ Feature
SMBus Dial-a-frequency feature is available in this device via Bytes 6, 7 and 8.
These bytes allow the user to enter the N and R values that will enable them to program any CPU frequency desired
following the formula:
P × N
Fcpu =
R
Where N and R values are programmed in binary into Bytes 6 & 7 for N and Byte 8 for R. See table below for min
and max allowed values.
R
Min N
44
45
46
47
48
49
50
51
Max N
87
90
92
94
96
98
100
102
104
107
42
43
44
45
46
47
48
49
50
51
52
53
Cypress Semiconductor Corporation
525 Los Coches St.
Document#: 38-07070 Rev. **
5/4/2001
Milpitas, CA 95035. Tel: 408-263-6300, Fax: 408-263-6571
http://www.cypress
Page 10 of 21
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