SH7014 Datasheet, PDF (588/754 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer

21. Power-Down State
21.3 Sleep Mode
21.3.1 Transition to Sleep Mode
Executing the SLEEP instruction when the SBY bit of SBYCR is 0 causes a transition from the
program execution state to the sleep mode. Although the CPU halts immediately after executing
the SLEEP instruction, the contents of its internal registers remain unchanged. The on-chip
peripheral modules continue to run during the sleep mode.
21.3.2 Canceling Sleep Mode
Sleep mode is canceled by an interrupt, DMAC address error, or power-on reset.
Cancellation by an Interrupt: When an interrupt occurs, the sleep mode is canceled and interrupt
exception processing is executed. The sleep mode is not canceled if the interrupt cannot be
accepted because its priority level is equal to or less than the mask level set in the CPU's status
register (SR) or if an interrupt by an on-chip peripheral module is disabled at the peripheral
module.
Cancellation by a DMAC Address Error: If a DMAC address error occurs, the sleep mode is
canceled and DMAC address error exception processing is executed.
Cancellation by a Power-On Reset: A power-on reset resulting from setting the RES pin to low
level cancels the sleep mode.
21.4 Standby Mode
21.4.1 Transition to Standby Mode
To enter the standby mode, set the SBY bit to 1 in SBYCR, then execute the SLEEP instruction.
The LSI moves from the program execution state to the standby mode. In the standby mode,
power consumption is greatly reduced by halting not only the CPU, but the clock and on-chip
peripheral modules as well. CPU register contents and on-chip RAM data are held as long as the
prescribed voltages are applied. The register contents of some on-chip peripheral modules are
initialized, but some are not (table 21.3). The I/O port status can be selected as held or high
impedance by the port high impedance bit (HIZ) of the SBYCR. For pin status other than for the
I/O port, refer to Appendix B, Pin Status.
Rev.5.00 Sep. 27, 2007 Page 554 of 716
REJ09B0398-0500