AN2077 Motorola / Freescale Semiconductor, AN2077 Datasheet - Page 2

• Manufacturer Part Number: AN2077
• Description: PowerPC Design Checklist
• Manufacturer: Motorola / Freescale Semiconductor

1.1 Introduction
The PowerPC processor and PCI bridge/memory controller family are all easy to design to, as long as some
simple rules are followed regarding connections and pullups. For reference purposes, many designers refer
to the application notes and example designs on the Motorola PowerPC website. This application note is a
simple checklist that is useful before finalizing the design.
1.2 Connections
This section summarizes the connections and special conditions (such as pullups or pulldowns required)
which may be needed for processors and memory controllers. Table 1 lists connections for the MPC603,
MPC75x, MPC74x0 and MPC824x microprocessors/microcontrollers, while Table 2 lists connections for
the MPC8240, MPC8245 and MPC107 microcontrollers/system controllers. The older MPC604 and
MPC106 devices are not listed in the tables; the MPC603 and MPC107 entries are very similar and can be
used instead.
In the tables, if a connection to a specific signal is not named, it may be one of the following terms:
Lastly, some of the signals have a “critical” designation:
This designator indicates signals which can cause system failure if not properly handled. If a new design is
not running cycles (i.e., logic analyzer traces cannot be captured), the indicated signals should be checked
first to determine if the conditions required are present. If not, due to design or manufacturing error, the part
may be improperly configured into a test mode and will not operate as desired.
As an example, consider transfer start (TS). On an MPC107-based design, if a pullup is not present, TS may
float low, indicating to both the MPC107 and the CPU that another device is using the bus. Each will wait
for the other to release TS, and so the system will not start. A simple pullup insures that each device sees an
idle bus.
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xx-yy OVDD
xx-yy GND
“open”
“as needed”
A pullup resistor to the OVDD power supply, with a value between xx and
yy ohms.
A pulldown resistor to the ground power connection, with a value between
xx and yy ohms.
The signal may/should be left unconnected.
The connection is determined principally by the sysem.
May cause complete failure; board will likely not operate
PowerPC Design Checklist