SH7721 datasheet(553/1524 Pages) RENESAS

553 / 1524 page

Section 13

Power-Down Modes

Rev. 3.00

Jan. 18, 2008

Page 491 of 1458

REJ09B0033-0300

13.6

Module Standby Function

13.6.1

Transition to Module Standby Function

Setting the MSTP bits in the standby control register to 1 halts the supply of clocks to the

corresponding on-chip peripheral modules. This function can be used to reduce power

consumption in normal mode. When changing the setting of an MSTP bit to use the module

standby function, be sure to halt operation of the module whose clock supply is to be stopped

before setting the corresponding MSTP bit to 1.

In the module standby state, the states of the external pins of the on-chip peripheral modules differ

depending on the on-chip peripheral module and I/O port settings. Register state is as same as in

standby mode. When changing the setting of an MSTP bit to use the module standby function, be

sure to halt operation of the module whose clock supply is to be stopped before setting the

corresponding MSTP bit to 1.

13.6.2

Canceling Module Standby Function

The module standby function can be canceled by clearing the MSTP bits to 0, or by a power-on

reset.

When canceling the module standby function by clearing the corresponding MSTP bit, be sure to

read the relevant MSTP bit to confirm that it has been cleared to 0.

SH7721 Datasheet(PDF) 553 Page - Renesas Technology Corp