2.6
CPU States
2.6.1
Overview
The CPU has three states: the program execution state, exception-handling state, and power-down
state. The power-down state is further divided into three modes: sleep mode, software standby
mode, and hardware standby mode. Figure 2.11 summarizes these states, and figure 2.12 shows a
map of the state transitions.
Program execution state
State
The CPU executes successive program instructions.
Exception-handling state
A transient state triggered by a reset or interrupt. The CPU executes
a hardware sequence that includes loading the program counter from
the vector table.
Sleep mode
Power-down state
A state in which some or
all of the chip functions are
stopped to conserve power.
Software standby mode
Hardware standby mode
Figure 2.11 Operating States
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RENESAS [ RENESAS TECHNOLOGY CORP ]
