ICS94228 Datasheet, PDF (2/17 Pages) Integrated Circuit Systems – Programmable System Clock Chip for AMD - K7™ processor

ICS94228
Pin Descriptions
PIN NUMBER
1, 15, 23, 25,
2, 8, 12, 19,
29, 37, 43
3
4
5
6
7
9
10
21, 20, 18, 17,
16, 14, 13, 11
22
24
28, 27, 26
30
31
32
33
34
35
36
38
39
40
42
41
44
45
46
47
48
PIN NAME
VDD
GND
X1
X2
AVDD48
FS2^{1, 2}
48MHz
FS3^{1, 2}
24_48MHz
PCICLK_F
SEL24_48#^{1, 2}
PCICLK0
PCICLK (8:1)
PCICLK9_E
SRESET#¹
AGP (2:0)
SCLK
SDATA
AGND
AVDD
PD#
PCI_STOP#
CPU_STOP#^{1, 2}
CPUCLK_CSC0
CPUCLK_CST0
VDDL
CPUCLKT0
CPUCLKC0
AGP_STOP#
REF_STOP#
REF_F
FS1^{1, 2}
REF1
FS0^{1, 2}
REF0
TYPE
PWR Power supply, nominal 3.3V
DESCRIPTION
PWR Ground
IN
OUT
PWR
IN
OUT
IN
OUT
OUT
IN
OUT
Crystal input, has internal load cap (36pF) and feedback resistor from X2
Crystal output, nominally 14.318MHz. Has internal load cap (36pF)
Power supply, nominal 3.3V
Frequency select pin. Latched Input
48MHz output clock, stoppable by REF_Stop
Frequency select pin. Latched Input
24 or 48MHz clock output, stoppable by REF_Stop
Free running PCI clock not affected by PCI_STOP# for power management.
Logic input to select 24 or 48MHz for pin 7 output
PCI clock output
OUT PCI clock outputs.
OUT
OUT
OUT
IN
I/O
PWR
PWR
IN
IN
IN
OUT
OUT
PWR
OUT
OUT
IN
IN
OUT
IN
OUT
IN
OUT
Early PCI clock. Leads general PCI clocks by 2ns. Can be stopped by PCI_STOP#.
Real time system reset signal for watchdog tmer timeout. This signal is active low.
AGP clock outputs
Clock input of I²C input, 5V tolerant input
Data pin for I²C circuitry 5V tolerant
Analog ground
Power supply, nominal 3.3V
Asynchronous active low input pin used to power down the device into a low
power state. The internal clocks are disabled and the VCO and the crystal are
stopped. The latency of the power down will not be greater than 3ms.
Stops all PCICLKs besides the PCICLK_F clocks at logic 0 level, when input low
This asynchronous input halts CPUCLKT, CPUCLKC & CUCLKC_CS clocks at logic
"0" level when driven low.
"Complementary" clock of differential pair output chipset (push-pull).
"True" clock of differential pair CPU output chipset (push-pull).
Power supply for CPUCLKs, nominal 2.5V
"True" clock of differential pair CPU output. These open drain outputs need an
external 1.5V pull-up (open drain).
"Complementary" clock of differential pair CPU output. These open drain outputs
need an external 1.5V pull-up (open drain).
Stops all AGP clocks at logic 0 level, when input low
Stops REF, 48MHz and 24/48MHz clocks at logic 0 level, when input low.
14.318 MHz free running reference clock., not afftected by REF_STOP#
Frequency select pin. Latched Input
14.318 MHz reference clock.
Frequency select pin. Latched Input
14.318 MHz reference clock.
Notes:
1: Internal Pull-up Resistor of 120K 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.
0447E—05/07/04
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