ICS9248-92 Datasheet, PDF (5/14 Pages) Integrated Circuit Systems – Mobile Pentium IITM System Clock Chip

ICS9248-92
Serial Configuration Command Bitmaps
Byte 0: Functional and Frequency Select Clock Register (default on Bits 7, 6, 5, 4, 1, 0 = 0)
Note: PWD = Power-Up Default
(default on Bits 3, 2 = 1)
BIT
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PIN#
-
-
-
23
22
-
DESCRIPTION
Reserved
Reserved
In Spread Spectrum, Controls type
(0=centered, 1=down spread)
In Spread Spectrum, Controls Spreading
(0=±0.5% 1=±0.25%)
48/24 MHz (Frequency Select) 1=48 MHz, 0=24 MHz
48/24 MHz (Frequency Select) 1=48 MHz, 0=24 MHz
Bit1 Bit0
1 1 - Tri-State
1
0 - Spread Spectrum Enable
0
1 - Testmode
0
0 - Normal operation
PWD
0
0
1
0
1
1
10
Select Functions
Functionality
Tristate
Testmode
CPU
HI - Z
TCLK/2¹
PCI,
PCI_F
HI - Z
TCLK/4¹
SDRAM
HI - Z
TCLK/2¹
REF
HI - Z
TCLK¹
24 MHz
Selection
HI - Z
TCLK/4¹
48 MHz
Selection
HI - Z
TCLK/2¹
Notes:
1. TCLK is a test clock driven on the X1 (crystal in pin) input during test mode.
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