
AMD Geode SC1200/SC1201 Processor Data Book
27
Signal Definitions
Revision 7.1
3.1
Ball Assignments
The SC1200/SC1201 processor is highly configurable as
ister programming are used to set various modes of opera-
tion and specific signals on specific balls. This section
describes which signals are available on which balls and
provides configuration information:
trations of EBGA and TEPBGA ball assignments.
signals according to ball number. Power Rail, Signal
Type, Buffer Type and, where relevant, Pull-Up or Pull-
Down resistors are indicated for each ball in this table.
For multiplexed balls, the necessary configuration for
each signal is listed as well.
reference signal list sorted alphabetically - listing all
signal names and ball numbers.
The tables in this chapter use several common abbrevia-
tions.
Table 3-1 lists the mnemonics and their meanings
Notes:
1)
For each GPIO signal, there is an optional pull-up
resistor on the relevant ball. After system reset, the
pull-up is present.
This pull-up resistor can be disabled via registers in the
Core Logic module. The configuration is without regard to
the selected ball function (except for GPIO12, GPIO13,
and GPIO16). Alternate functions for GPIO12, GPIO13,
and GPIO16 control pull-up resistors.
2)
Configuration settings listed in this table are with
regard to the Pin Multiplexing Register (PMR). See
description of this register.
Table 3-1. Signal Definitions Legend
Mnemonic
Definition
A
Analog
AVSS
Ground ball: Analog
AVCC
Power ball: Analog
GCB
General Configuration Block registers.
Location of the General Configuration
Block cannot be determined by software.
See AMD Geode SC1200/SC1201
Processor Specification Update docu-
ment.
I
Input ball
I/O
Bidirectional ball
MCR[x]
Miscellaneous Configuration Register
Bit x: A register, located in the GCB.
details.
O
Output ball
OD
Open-drain
PD
Pull-down
PMR[x]
Pin Multiplexing Register Bit x: A regis-
ter, located in the GCB, used to config-
ure balls with multiple functions. Refer to
details.
PU
Pull-up
TS
TRI-STATE
VCORE
Power ball: 1.2V
VIO
Power ball: 3.3V
VSS
Ground ball
#
The # symbol in a signal name indicates
that the active or asserted state occurs
when the signal is at a low voltage level.
Otherwise, the signal is asserted when
at a high voltage level.
/
A / in a signal name indicates both func-
tions are always enabled (i.e., cycle mul-
tiplexed).
+
A + in signal name indicates the function
is available on the ball, but that either
strapping options or register program-
ming is required to select the desired
function.