44
T
1
state
Bus cycle
Internal
address bus
Internal
read signal
Internal
data bus
(read access)
Internal
write signal
Read data
Address
Internal
data bus
(write access)
T
2
state
T
3
state
Write data
SUB
ø or ø
Figure 2.13 On-Chip Peripheral Module Access Cycle (3-State Access)
2.7
CPU States
2.7.1
Overview
There are four CPU states: the reset state, program execution state, program halt state, and
exception-handling state. The program execution state includes active (high-speed or medium-
speed) mode and subactive mode. In the program halt state there are a sleep mode, standby mode,
watch mode, and sub-sleep mode. These states are shown in figure 2.14.
Figure 2.15 shows the state transitions.