+/+…when timing is critical
C9829B
Low EMI Clock Generator for Intel 133MHz/3DIMM Chipset Systems
Approved Product
™
™
Byte 6: Dial-a-Frequency Register
Byte 8: Dial-a-Frequency Register
Bit
7
6
5
4
3
2
1
0
@Pup
Pin#
Description
N9, MSB
N8
N7
N6
N5
N4
N3
N2
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
-
-
-
-
-
-
-
-
0
0
0
0
0
0
0
0
-
-
-
-
-
-
-
-
™
Byte 7: Dial-a-Frequency Register
Bit
7
6
5
4
3
2
1
0
@Pup
Pin#
Description
N1
N0, LSB
Enable I2C N values
Enable I2C R values
Reserved
Reserved
Reserved
Reserved
0
0
0
0
0
0
0
0
-
-
-
-
-
-
-
-
Dial-a-Frequency™ Feature
I2C 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
INTERNATIONAL MICROCIRCUITS, INC. 525 LOS COCHES ST.,
MILPITAS, CA 95035, USA. TEL: 408-263-6300, FAX 408-263-6571
http://www.imicorp.com
Rev 1.3
4/12/2000
Page 10 of 20
CYPRESS [ CYPRESS ]
