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M30245 Group
3.9 Controlling Power Using Wait Mode
Overview
The following are steps for controling power using wait mode. Figure 3.9.1 shows the operation
timing, and Figures 3.9.2 to 3.9.4 show the set-up procedure.
Use the following peripheral functions:
• Timer mode of timer A
• Wait mode
A flag named "F-WIT" is used in the set-up procedure. The purpose of this flag is to decide
whether or not to clear wait mode. If F_WIT = "1" in the main program, the wait mode is entered;
if F_WIT = "0", the wait mode is cleared.
Specifications
(1) Connect a 32.768-kHz oscillator to X
occur every one second, which is a count the timer reaches, the controller returns from wait
mode and count the clock using a program.
(2) Clear wait mode if a INT0 interrupt request occurs.
Operation
(1) Switch the system clock from X
(2) Stop X
(3) When a timer A2 interrupt request occurs (at 1-second intervals), start supplying the BCLK
from X
and enter wait mode again.
_______
(4) If a INT0 interrupt occurs, start supplying the BCLK from X
_______
the INT0 interrupt, and switch the system clock to X
X
OUT
X
CIN
Timer A2 overflow
Timer A2
interrupt processing
INT
0
BCLK
Figure 3.9.1. Operation timing of controling power using wait mode
Rev.2.00 Oct 16, 2006
REJ09B0340-0200
________
and enter wait mode. In this instance, enable the timer A2 interrupt and the INT0 interrupt.
IN
At this time, count the clock within the routine that handles the timer A2 interrupts
CIN.
(1) Shift to low-speed mode
(2) Stop X
IN
(3) Timer A2 interrupt
"H"
"L"
High-speed
Low-speed
page 325 of 354
to serve as the timer count source. As interrupts
CIN
to X
to get low-speed mode.
IN
CIN
.
IN
Low-speed
Low-speed
3. Controlling Power Applications
_______
. Start the X
oscillation within
CIN
IN
(4) INT
interrupt
0
High-speed
Low-speed
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