+/+…when timing is critical
C9810
Low EMI Clock Generator for Intel 810 Chipset for Mobile Applications
Advanced Information
Serial Control Registers
IMI Confidential
NOTE: The Pin# column lists the affected pin number where applicable. The @Pup column gives the state at true
power up. Bytes are set to the values shown only on true power up.
In write mode, following the acknowledge of the Address Byte (D2), two additional bytes must be sent:
1) “Command Code“ byte, and
2) “Byte Count” byte.
Although the data (bits) in these two bytes are considered “don’t care”; they must be sent and will be acknowledged.
After the Command Code and the Count bytes have been acknowledged, the sequence (Byte 0, Byte 1, and Byte2)
described in Fig7 will be valid and acknowledged.
In the Read Mode (See Fig7B, p.8), the clock gen. acknowledges Address D3, and immediately transmits data starting
with Byte count, then Byte 0, 1, 2, ... After each transmitted byte, this device waits for an acknowledge before
transmitting the next byte.
Byte 0: CPU Clock Register (1=Enable, 0=Disable, Default=07)
Byte 3: Reserved Register (Default=00)
Byte 4: Reserved Register (Default=00)
Bit
7
6
5
4
3
2
1
0
@Pup
Pin#
-
-
-
-
Description
Reserved
Reserved
Reserved
Reserved
Spread Spectrum
DOT
0
0
0
0
0
1
1
1
Byte 5: SSCG Control Register (Default=00)
Bit
7
@Pup
0
Description
Spread Spectrum Mode (0=down,
1=center)
-
24
23
41
USB
CPU2
6
5
4
3
2
1
0
0
0
0
0
0
0
0
Ref. Table 4
Ref. Table 4
Reserved
Reserved
Reserved
Byte 1: SDRAM Clock Register (1=Enable, 0=Disable, Default=EC)
Bit
7
6
5
4
3
2
1
0
@Pup
Pin#
32
33
35
-
37
38
-
Description
SDRAM3
SDRAM2
DCLK
Reserved
SDRAM1
SDRAM0
Reserved
Reserved
Reserved
Reserved
1
1
1
0
1
1
0
0
-
Byte 2: PCI Clock Register (1=Enable, 0=Disable, Default=FE)
Bit
7
6
5
4
3
2
1
0
@Pup
Pin#
18
17
15
14
12
11
10
-
Description
PCI6
PCI5
PCI4
PCI3
PCI2
PCI1
PCI0
Reserved
1
1
1
1
1
1
1
0
INTERNATIONAL MICROCIRCUITS, INC. 525 LOS COCHES ST.
MILPITAS, CA 95035, USA TEL: 408-263-6300, FAX 408-263-6571
Rev 0.4
8/31/1999
Page 7 of 15
http://www.imicorp.com
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