ICS9248-127 Datasheet, PDF (2/14 Pages) Integrated Circuit Systems – Frequency Generator & Integrated Buffers for PENTIUM/ProTM

ICS9248 - 127
Pin Descriptions
PIN NUMBER PIN NAME
1, 6, 14, 19, 27, 30,
36, 47
VDD
REF0
2
PCI_STOP#¹
3,9,16,22,
33,40,44
GND
4
X1
5
X2
PCICLK_F
7
MODE^{1, 2}
FS3¹
8
PCICLK0
13, 12, 11, 10 PCICLK (4:1)
15
17, 18, 20, 21, 28,
29, 31, 32, 34, 35,
37, 38
BUFFER IN
SDRAM (11:0)
23
SDATA
24
SCLK
24MHz
25
FS1^{1, 2}
48MHz
26
FS0^{1, 2}
39
SDRAM_F
41
CLK_STOP#
42, 43, 45
46
48
CPUCLK (2:0)
CPUCLK_F
REF1
FS2^{1, 2}
TYPE
DESCRIPTION
PWR 3.3V power supply
OUT
IN
14.318 Mhz reference clock.This REF output is the STRONGER
buffer for ISA BUS loads
Halts PCICLK clocks at logic 0 level, when input low
(In mobile mode, MODE=0)
PWR Ground
IN
OUT
OUT
IN
IN
OUT
OUT
IN
Crystal input, has internal load cap (36pF) and feedback
resistor from X2
Crystal output, nominally 14.318MHz.
Free running PCI clock not affected by PCI_STOP# for power
management.
pin 2 function select pin, 1=Desktop Mode, 0=Mobile Mode.
Latched Input.
Frequency select pin. Latched Input.
PCI clock outputs. Syncheronous to CPU clocks with 1-4ns skew
(CPU early)
PCI clock outputs. Syncheronous to CPU clocks with 1-4ns skew
(CPU early)
Input to Fanout Buffers for SDRAM outputs.
OUT
SDRAM clock outputs, Fanout Buffer outputs from BUFFER IN pin
(controlled by chipset).
I/O
IN
OUT
IN
OUT
IN
OUT
IN
OUT
OUT
OUT
IN
Data pin for I²C circuitry 5V tolerant
Clock pin of I²C circuitry 5V tolerant
24MHz output clock
Frequency select pin. Latched Input.
48MHz output clock
Frequency select pin. Latched Input
Free running SDRAM clock output. Not affected by CPU_STOP#
This asynchronous input halts CPUCLK & SDRAM at logic "0"
level when driven low.
CPU clock outputs, powered by VDDCPU
Free running CPU clock. Not affected by the CPU_STOP#
14.318 MHz reference clock.
Frequency select pin. Latched Input
Notes:
1: Internal Pull-up Resistor of 240K to 3.3V on indicated inputs
2: Bidirectional input/output pins, input logic levels are latched at internal power-on-reset. Use 10Kohm resistor to
program logic Hi to VDD or GND for logic low.
2