Notes On Standby Mode; Module Standby Function; Transition To Module Standby Function; Clearing The Module Standby Function - Hitachi SH7095 Hardware User Manual

14.4.5

Notes on Standby Mode

(1) Disable the cache before transitting to the standby mode when the SH7095 enters the standby
mode during using the cache. Initialize the cache beforehand when the cache is used after
returning to the standby mode. The value of the on-chip RAM is not held in the standby mode
although the cache is used as the on-chip RAM.
(2) Read the corresponding register and execute the SLEEP instruction when the on-chip
peripheral register is written in 10 clock cycles before the SH7095 transits to the standby
mode.
(3) When the standby mode is used by clock modes 0.1, and 2, the CKIO pin is the clock output
pin. Note the following when the standby mode is used in this clock mode. When the standby
mode is canceled by NMI, an unstable clock is output from the CKIO pin during oscillation
setting time after the NMI is input. The clock is output as well as by cancellation by power-on
reset and manual reset. Input power-on reset and manual reset for the equal to or more time
than the oscillation setting time.
14.5

Module Standby Function

14.5.1

Transition to Module Standby Function

By setting the standby control register MSTP4–MSTP0 bits to 1, the supply of clock to the
corresponding registers can be halted (table 14.4). This function can be used to reduce the power
consumption in sleep mode. Do not read/write each module in the module standby.
The external pins or registers in the on-chip peripheral modules of the DMAC, MULT and DIVU
hold the states before halting. The external pins of the FRT and SCI are reset and all their registers
are initialized.
Do not put on-chip peripheral modules into module standby while they are running.
14.5.2

Clearing the Module Standby Function

Clear the module standby function by clearing the MSTP4–MSTP0 bits or by a power-on reset or
manual reset.
To enter module stop, stop any oeprating modules or disable interrupts.
Hitachi 383