IBM25PPC440GX IBM Microelectronics, IBM25PPC440GX Datasheet - Page 40

• Manufacturer Part Number: IBM25PPC440GX
• Description: PowerPC 440GX Embedded Processor
• Manufacturer: IBM Microelectronics

Preliminary
Signal Description
The PPC440GX embedded controller is packaged in a 552-ball ceramic ball grid array (CBGA). The following
tables describe the package level pinout.
In the table “Signal Functional Description” on page 41, each I/O signal is listed along with a short description
of its function. Active-low signals (for example, RAS) are marked with an overline. Please see “Signals Listed
Alphabetically” on page 15 for the pin (ball) number to which each signal is assigned.
Multiplexed Signals
Some signals are multiplexed on the same pin so that the pin can be used for different functions. In most
cases, the signal names shown in this table are not accompanied by signal names that may be multiplexed
on the same pin. If you need to know what, if any, signals are multiplexed with a particular signal, look up the
name in “Signals Listed Alphabetically” on page 15. It is expected that in any single application a particular
pin will always be programmed to serve the same function. The flexibility of multiplexing allows a single chip
to offer a richer pin selection than would otherwise be possible.
Multipurpose Signals
In addition to multiplexing, some pins are also multi-purpose. For example, the EBC peripheral controller
address pins (PerAddr00:31) are used as outputs by the PPC440GX to broadcast an address to external
slave devices when the PPC440GX has control of the external bus. When during the course of normal chip
operation an external master gains ownership of the external bus, these same pins are used as inputs which
are driven by the external master and received by the EBC in the PPC440GX. In this example, the pins are
also bidirectional, serving both as inputs and outputs.
Multimode Signals
In some cases (for example, Ethernet) the function of a pin may vary with different modes of operation. When
a pin has multiple signal names assigned to distinguish different modes of operation, all of the names are
shown.
Strapping Pins
One group of pins is used as strapped inputs during system reset. These pins function as strapped inputs
only during reset and are used for other functions during normal operation (see “Strapping” on page 72). Note
that these are not multiplexed pins since the function of the pins is not programmable.
Page 40 of 74
Pin Summary
PowerPC 440GX Embedded Processor Data Sheet
Signal pins, non-multiplexed
Signal pins, multiplexed
Total Signal Pins
Total Power Pins
Total Pins
Reserved
Group
AxV
AGnd
OV
SV
V
Gnd
DD
DD
DD
DD
No. of Pins
343
406
146
552
63
27
34
70
3
3
9
0
2/12/04