3.8 CPU States
3.8.1 Overview
The CPU has five states: the program execution state, exception-handling state, bus-released state,
reset state, and power-down state. The power-down state is further divided into the sleep mode,
software standby mode, and hardware standby mode. Figure 3-11 summarizes these states, and
figure 3-12 shows a map of the state transitions.
Write cycle
T state
1 T state2 T state3
Address
Write data
“High”
R/W
D –D70
A –A19 0
ø
AS
WR
DS
RD
Figure 3-10 (b) External Access Cycle (Write Access)
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