
PRODUCT SPECIFICATION
RC7144
3
P
Pin Description
Pin Name
V
DDQ3
Pin #
Pin Type
PWR
Pin Function
1, 6, 14, 19,
27, 30, 36
Power connection:
Power supply for core logic, PLL circuitry SDRAM
outputs, PCI outputs, reference, 48 & 24 MHz outputs. Connect to 3.3
Volts.
I/O Dual function REF0 & PCI_STOP#:
Function determined by
MODE pin. When high, this pin is an output with 14.31818 MHz of
reference clock. When MODE is low, PCI_STOP# stops all the PCI
clocks.
Ground connection:
Connect all ground pins to the common system
ground plane.
Crystal Connection:
An input connection for an external 14.318 MHz
crystal. 18 pF internal cap.
Crystal Connection or External Reference Frequency:
This pin has
dual functions. It can be used as an external 14.318 MHz crystal
connection or as an external reference frequency input.
Fixed PCI clock output:
Upon power up MODE input will be latched,
which will enable or disable REF0.
PCI clock output:
Upon power up FS3 input will be latched, which will
set clock frequencies as frequency selection table. This pin has internal
pull down.
PCI clock output 2 through 5:
These five PCI clock outputs are
controlled by the PCI_STOP# control pin.
Buffered input pin:
The signal provided to this input pin is buffered to
13 outputs.
SDRAM Clock Ouputs:
SDRAM0:11 clock are determined by
FS0: FS3. SDRAM_F is a free running clock which is not controlled
by the I
2
C.
REF0/
PCI_STOP#
2
OUT/IN
GND
3, 9, 16, 22,
33, 39, 45
4
PWR
X1
IN
X2
5
OUT
PCI_F/MODE
7
OUT/IN
PCI1/FS3
8
OUT/IN
PCI2:5
10, 11, 12, 13
OUT
SDRAM_IN
15
IN
SDRAM0:11;
SDRAM_F
17, 18, 20, 21,
28, 29, 31, 32,
34, 35, 37, 38,
40
23
24
25
OUT
SDA
SCL
24MHz/FS1
IN/OUT
IN
OUT/IN
Data pin for I
2
C circuitry.
Clock pin for I
2
C circuitry.
24 MHz clock output:
24 MHz is provided in normal operation. In
standard systems, this output can be used as the clock input for Super
I/O chip. Upon power up FS1 input will be latched, which will set clock
frequencies as frequency selection table.
48 MHz clock output:
48 MHz is provided in normal operation. In
standard systems, this output can be used as the reference for
universal Serial Bus. Upon power up FS0 input will be latched, which
will set clock frequencies as frequency selection table.
CLK_STOP# Input:
When 0, this pin stops the CPU outputs after
completing a full clock cycle. This pin does not effect CPU_F.
Power supply for IOAPIC & all CPU outputs. Connect to 2.5 or 3.3
Volts.
CPU output clocks:
V
DDQ2
controls output Voltage. Stopped when
CLK_STOP# is 0. CPU_F is not affected by CLK_STOP#.
Reference Clock output:
14.31818 MHz reference output. Upon
power up FS2 input will be latched, which will set clock frequencies as
frequency selection table.
IOAPIC clock:
Provides 14.31818 MHz fixed clock. V
DDQ2
contols the
output Voltage.
48MHz/FS0
26
OUT/IN
CLK_STOP#
41
IN
V
DDQ2
42, 48
PWR
CPU1,
CPU_F
REF1/FS2
43, 44
OUT
46
OUT/IN
IOAPIC
47
OUT