HD64F3670 Datasheet, PDF (89/305 Pages) Renesas Technology Corp – Hitachi Single-Chip Microcomputer

Section 6 Power-down Modes
This LSI has six modes of operation after a reset. These include a normal active mode and four
power-down modes, in which power dissipation is significantly reduced. The module standby
mode reduces power dissipation by selectively halting on-chip module functions.
• Active mode
The CPU and all on-chip peripheral modules are operable on the system clock. The system
clock frequency can be selected from øosc, øosc/8, øosc/16, øosc/32, and øosc/64.
• Sleep mode
The CPU halts. On-chip peripheral functions are operable on the system clock.
• Standby mode
The CPU and all on-chip peripheral modules halt.
• Subsleep mode
The CPU and all on-chip peripheral modules halt.
I/O ports keep the same states as before the transition.
• Module standby mode
Independent of the above modes, power dissipation can be reduced by halting on-chip modules
that are not used in module units.
6.1 Register Descriptions
The registers related to power-down modes are listed below. For details on register addresses and
register states during each processing, refer to appendix B, Internal I/O Register.
• System control register 1(SYSCR1)
• System control register 2(SYSCR2)
• Module standby control register 1(MSTCR1)
• Module standby control register 2(MSTCR2)
6.1.1 System Control Register 1(SYSCR1)
The SYSCR1 register controls the power-down modes, as well as SYSCR2.
Rev. 1.0, 03/01, page 65 of 280