SH7751 Datasheet, PDF (346/1224 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer

9. Power-Down Modes
9.3 Sleep Mode
9.3.1 Transition to Sleep Mode
If a SLEEP instruction is executed when the STBY bit in STBCR is cleared to 0, the chip switches
from the program execution state to sleep mode. After execution of the SLEEP instruction, the
CPU halts but its register contents are retained. The on-chip peripheral modules continue to
operate, and the clock continues to be output from the CKIO pin.
In sleep mode, a high-level signal is output at the STATUS1 pin, and a low-level signal at the
STATUS0 pin.
9.3.2 Exit from Sleep Mode
Sleep mode is exited by means of an interrupt (NMI, IRL, or on-chip peripheral module) or a
reset. In sleep mode, interrupts are accepted even if the BL bit in the SR register is 1. If necessary,
SPC and SSR should be saved to the stack before executing the SLEEP instruction.
Exit by Interrupt: When an NMI, IRL, or on-chip peripheral module interrupt is generated, sleep
mode is exited and interrupt exception handling is executed. The code corresponding to the
interrupt source is set in the INTEVT register.
Exit by Reset: Sleep mode is exited by means of a power-on or manual reset via the RESET pin,
or a power-on or manual reset executed when the watchdog timer overflows.
9.4 Deep Sleep Mode
9.4.1 Transition to Deep Sleep Mode
If a SLEEP instruction is executed when the STBY bit in STBCR is cleared to 0 and the DSLP bit
in STBCR2 is set to 1, the chip switches from the program execution state to deep sleep mode.
After execution of the SLEEP instruction, the CPU halts but its register contents are retained.
Except for the DMAC*, on-chip peripheral modules continue to operate. The clock continues to be
output to the CKIO pin, but all bus access (including auto refresh) stops. When using memory that
requires refreshing, set the self-refresh function prior to making the transition to deep sleep mode.
In deep sleep mode, a high-level signal is output at the STATUS1 pin, and a low-level signal at
the STATUS0 pin.
Rev.4.00 Oct. 10, 2008 Page 248 of 1122
REJ09B0370-0400