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Introduction
1.4 POWER MANAGEMENT
The MPC823e microprocessor supports a wide range of power management features,
including normal high, normal low, doze, sleep, deep-sleep, and power-down modes. In
normal high mode, the MPC823e microprocessor is fully powered with all internal units
operating at the full speed of the processor. Normal low mode is the same as normal high,
except it operates at a much lower frequency. There is a doze mode determined by a clock
divider that allows the operating system to reduce the operational frequency of the
processor.
Doze mode disables core functional units except the timebase, decrementer, PLL, memory
controller, real-time clock, LCD controller, and communication processor module. Sleep
mode is a lower power mode that disables everything except the real-time clock, timebase,
decrementer, and periodic interrupt timer, thus leaving the PLL active for quick wake-up.
The deep-sleep mode then disables the PLL for lower power, but slower wake-up.
Power-down mode disables all logic in the processor, except the minimum logic required to
restart the device. It saves the most power, but requires the longest wake-up time.
1.5 SYSTEM DEBUG SUPPORT
The MPC823e microprocessor contains an advanced debug interface that provides superior
debug capabilities without any loss of speed. It supports six watchpoint pins that can be
combined with eight internal comparators, four of which operate on the effective address of
the address bus. The other four comparators are split—two comparators operate on the
effective address on the data bus and two comparators operate on the data on the data bus.
The MPC823e microprocessor can compare using the =, ≠, <, and > conditions to generate
watchpoints. Each watchpoint can then generate a breakpoint that can be programmed to
trigger in a programmable number of events.
1.6 APPLICATIONS
The MPC823e microprocessor is specifically designed to be a general-purpose, low-cost
entry point to the Motorola embedded PowerPC Family for systems in which advanced
GUIs, communications, and high-level real-time operating systems are used. The device
excels in applications that require the performance of single-issue PowerPC core with a
moderate amount of data and instruction cache. It provides all the basic features of glueless
memory connections along with functional serial connectivity, a graphical LCD, and a video
display controller. The MPC823e excels in low-power and portable applications because of
its extensive power-down modes and low normal operation current.
MOTOROLA
MPC823e REFERENCE MANUAL
1-11
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