Renesas H8S/2318 series, Hardware Manual

Page: 815 / 1121

Rev. 5.00, 12/03, page 785 of 1088
19.4 Sleep Mode
If a SLEEP instruction is executed when the SSBY bit in SBYCR is cleared to 0, the CPU enters
sleep mode. In sleep mode, CPU operation stops but the contents of the CPU’s internal registers
are retained. Other supporting modules do not stop.
Sleep mode is cleared by a reset or any interrupt, and the CPU returns to the normal program
execution state via the exception handling state. Sleep mode is not cleared if interrupts are
disabled, or if interrupts other than NMI are masked by the CPU.
When the
STBY
pin is driven low, a transition is made to hardware standby mode.
19.5 Module Stop Mode
19.5.1 Module Stop Mode
Module stop mode can be set for individual on-chip supporting modules.
When the corresponding MSTP bit in MSTPCR is set to 1, module operation stops at the end of
the bus cycle and a transition is made to module stop mode. The CPU continues operating
independently.
Table 19-3 shows MSTP bits and the corresponding on-chip supporting modules.
When the corresponding MSTP bit is cleared to 0, module stop mode is cleared and the module
starts operating at the end of the bus cycle. In module stop mode, the internal states of modules
other than the SCI and A/D converter are retained.
After reset clearance, all modules other than DTC are in module stop mode.
When an on-chip supporting module is in module stop mode, read/write access to its registers is
disabled.
Do not make a transition to sleep mode with MSTPCR set to H'FFFF or H'EFFF, as this will halt
operation of the bus controller.