
66
AMD Geode SC1200/SC1201 Processor Data Book
Signal Definitions
Revision 7.1
DID1
D2
C6
I
Device ID. Together, the straps on these sig-
nals define the system-level chip ID.
The value of DID1 can be read in the
MCR[29]. The value of DID0 can be read in
the MCR[31].
DID1 and DID0 should be connected to a 1.5
K
pull-down resistor to ensure a low level at
power-up.
GNT1#
DID0
D4
C5
I
GNT0#
POR#
J29
AH9
I
Power On Reset. POR# is the system reset
signal generated from the power supply to
indicate that the system should be reset.
---
X32I
C30
AJ2
I/O
Crystal Connections. Connected directly to
a 32.768 KHz crystal. This clock input is
required even if the internal RTC is not being
used. Some of the internal clocks are derived
from this clock. If an external clock is used, it
should be connected to X32I, using a voltage
level of 0 volts to VCORE +10% maximum.
X32O should remain unconnected.
---
X32O
D29
AJ3
---
X27I
A29
AG3
I/O
Crystal Connections. Connected directly to
a 27.000 MHz crystal. This clock input is
used for video circuits. Some of the internal
clocks are derived from this clock. If the inter-
nal TV encoder is used, a 25 ppm crystal is
recommended. If an external clock is used, it
should be connected to X27I, using a voltage
level of 0 volts to VIO and X27O should be
remain unconnected.
---
X27O
D27
AH2
---
CLK27M
A23
AA4
O
27 MHz Output Clock. Output of crystal
oscillator.
IDE_DATA5
PCIRST#
D1
A6
O
PCI and System Reset. PCIRST# is the
reset signal for the PCI bus and system. It is
asserted for approximately 100 s after
POR# is negated.
---
3.4.1
System Interface (Continued)
Signal Name
Ball No.
Type
Description
Mux
EBGA
TEPBGA
3.4.2
Memory Interface Signals
Signal Name
Ball No.
Type
Description
Mux
EBGA
TEPBGA
MD[63:0]
See
See
I/O
Memory Data Bus. The data bus lines
driven to/from system memory.
---
MA[12:0]
See
See
O
Memory Address Bus. The multiplexed row/
column address lines driven to the system
memory. Supports 256-Mbit SDRAM.
---