Section 19 Power-Down Modes; Overview - Hitachi H8S/2338 Series Hardware Manual

Section 19 Power-Down Modes

19.1

Overview

In addition to the normal program execution state, the H8S/2338 Series, H8S/2328 Series, and
H8S/2318 Series have five power-down modes in which operation of the CPU and oscillator is
halted and power dissipation is reduced. Low-power operation can be achieved by individually
controlling the CPU, on-chip supporting modules, and so on.
The H8S/2338 Series, H8S/2328 Series, and H8S/2318 Series operating modes are as follows:
1. High-speed mode
2. Medium-speed mode
3. Sleep mode
4. Module stop mode
5. Software standby mode
6. Hardware standby mode
Of these, 2 to 6 are power-down modes. Sleep mode is a CPU mode, medium-speed mode is a
CPU and bus master mode, and module stop mode is an on-chip supporting module mode
(including bus masters other than the CPU). A combination of these modes can be set.
After a reset, the H8S/2338 Series, H8S/2328 Series, or H8S/2318 Series chip is in high-speed
mode.
Table 19-1 shows the conditions for transition to the various modes, the status of the CPU, on-chip
supporting modules, etc., and the method of clearing each mode.
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