
932S890C
RD890 SYSTEM CLOCK FOR AMD-BASED SERVERS
IDT
RD890 SYSTEM CLOCK FOR AMD-BASED SERVERS
16
932S890C
REV D 052011
SMBUS Table: SR C Frequency Control Register
Byte
15
Name
Control Function
Type
0
1
Default
Bit 7
N Div2
N Divider Prog bit 2
R W
X
Bit 6
N Div1
N Divider Prog bit 1
R W
X
Bit 5
M Div5
R W
X
Bit 4
M Div4
R W
X
Bit 3
M Div3
R W
X
Bit 2
M Div2
R W
X
Bit 1
M Div1
R W
X
Bit 0
M Div0
R W
X
SMBUS Table: SR C Frequency Control Register
Byte
16
Name
Control Function
Type
0
1
Default
Bit 7
N Div10
R W
X
Bit 6
N Div9
RW
X
Bit 5
N Div8
RW
X
Bit 4
N Div7
RW
X
Bit 3
N Div6
RW
X
Bit 2
N Div5
RW
X
Bit 1
N Div4
RW
X
Bit 0
N Div3
RW
X
SMBUS Table: SR C Spread Spectrum Control Register
Byte
17
Name
Control Function
Type
0
1
Default
Bit 7
SSP7
R W
X
Bit 6
SSP6
R W
X
Bit 5
SSP5
R W
X
Bit 4
SSP4
R W
X
Bit 3
SSP3
R W
X
Bit 2
SSP2
R W
X
Bit 1
SSP1
R W
X
Bit 0
SSP0
R W
X
SMBUS Table: SR C Spread Spectrum Control Register
Byte
18
Name
Control Function
Type
0
1
Default
Bit 7
SSP15
R W
X
Bit 6
SSP14
R W
X
Bit 5
SSP13
R W
X
Bit 4
SSP12
R W
X
Bit 3
SSP11
R W
X
Bit 2
SSP10
R W
X
Bit 1
SSP9
R W
X
Bit 0
SSP8
R W
X
SMBus Table: SRC N Divider Control Register
Byte
19
Name
Control Function
Type
0
1
Default
Bit 7
SRC N Div0
LSB N Divider Programming
R W
X
Bit 6
0
Bit 5
0
Bit 4
0
Bit 3
0
Bit 2
0
Bit 1
0
Bit 0
0
Reserved
M Divider Programming
bit (5:0)
N Divider Programming
Byte16 bit(7:0) and Byte15
bit(7:6)
Reserved
N Divider LSB (bit 0) for SRC M/N programming.
The decimal representation of M and N Divider in Byte
15 and 16 configure the SRC VCO frequency. See
M/N Caculation Tables for VCO frequency formulas.
The decimal representation of M and N Divider in Byte
15 and 16 configure the SRC VCO frequency. See
M/N Caculation Tables for VCO frequency formulas.
Spread Spectrum
Programming bit(15:8)
Spread Spectrum
Programming bit(7:0)
These bits set the SRC spread pecentages.Please
contact IDT for the appropriate values.
These bits set the SRC spread pecentages.Please
contact IDT for the appropriate values.