AN1769 Freescale Semiconductor / Motorola, AN1769 Datasheet - Page 42

• Manufacturer Part Number: AN1769
• Description: Designing a Minimal PowerPC System
• Manufacturer: Freescale Semiconductor / Motorola

Part 9 Physical Layout
Figure 31 shows an example minimal system called Excimer; the size shown in an approximation of the
actual size.
This design uses the standard 255-pin BGA pattern to allow any MPC603x or MPC604x device to be
populated. An MPC750 design could be easily created by expanding the size for an additional two
PBSRAM devices. A user-deÞned I/O area allows customer-speciÞc interfaces to be attached.
Miscellaneous discrete components are not shown.
Part 10 Conclusion
A PowerPC design can be easily implemented with a small amount of hardware by following the examples
listed in this paper. The resulting system will exhibit fast memory access times and will allow benchmarking
of various processors. If desired, the design can be enhanced with the following features:
The possibilities are unlimited.
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Stream accesses to the same page of SRAM
Handle SRAM deselect in parallel with other accesses (even SRAM) to eliminate dead-time.
Support burst ßash memory
Move cycle recognition into the state machine; this eliminates one clock latency on all memory
cycles
Allow address-only cycles
21MHz
Freescale Semiconductor, Inc.
PC16552
66MHz
OSC
Serial Port 1
Figure 31. Excimer Minimal System Board
For More Information On This Product,
RS232
Minimal PowerPC System Design
Go to: www.freescale.com
PBSRAM
64K x 32
512K x 16
512K x 16
ispLSI2064V
Flash
Flash
Serial Port 2
RS232
PowerPC
MPC603
512K x 16
512K x 16
PBSRAM
64K x 32
Flash
Flash
POWER
DIN5
MOTOROLA