HD6432147SW datasheet(121/1177 Pages) RENESAS

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Section 2 CPU

Rev. 4.00 Sep 27, 2006 page 77 of 1130

REJ09B0327-0400

2.8.6

Power-Down State

The power-down state includes both modes in which the CPU stops operating and modes in which

the CPU does not stop. There are five modes in which the CPU stops operating: sleep mode,

software standby mode, hardware standby mode, subsleep mode, and watch mode. There are also

three other power-down modes: medium-speed mode, module stop mode, and subactive mode. In

medium-speed mode, the CPU and other bus masters operate on a medium-speed clock. Module

stop mode permits halting of the operation of individual modules, other than the CPU. Subactive

mode, subsleep mode, and watch mode are power-down modes that use subclock input. For

details, refer to section 25, Power-Down State.

Sleep Mode

A transition to sleep mode is made if the SLEEP instruction is executed while the software

standby bit (SSBY) in the standby control register (SBYCR) and the LSON bit in the low-power

control register (LPWRCR) are both cleared to 0. In sleep mode, CPU operations stop

immediately after execution of the SLEEP instruction. The contents of CPU registers are retained.

Software Standby Mode

A transition to software standby mode is made if the SLEEP instruction is executed while the

SSBY bit in SBYCR is set to 1 and the LSON bit in LPWRCR and the PSS bit in the WDT1 timer

control/status register (TCSR) are both cleared to 0. In software standby mode, the CPU and clock

halt and all MCU operations stop. As long as a specified voltage is supplied, the contents of CPU

registers and on-chip RAM are retained. The I/O ports also remain in their existing states.

Hardware Standby Mode

A transition to hardware standby mode is made when the

STBY pin goes low. In hardware

standby mode, the CPU and clock halt and all MCU operations stop. The on-chip supporting

modules are reset, but as long as a specified voltage is supplied, on-chip RAM contents are

retained.

HD6432147SW Datasheet(PDF) 121 Page - Renesas Technology Corp