m5m51016btp Renesas Electronics Corporation., m5m51016btp Datasheet - Page 334

• Manufacturer Part Number: m5m51016btp
• Description: Renesas 16-bit Single-chip Microcomputer M16c Family / M16c/20 Series
• Manufacturer: Renesas Electronics Corporation.

M30245 Group
Rev.2.00 Oct 16, 2006
REJ09B0340-0200
3.9 Controlling Power Using Wait Mode
Overview
Specifications
Operation
Figure 3.9.1. Operation timing of controling power using wait mode
X
X
Timer A2 overflow
Timer A2
interrupt processing
INT
BCLK
CIN
OUT
0
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.
(1) Connect a 32.768-kHz oscillator to X
(2) Clear wait mode if a INT0 interrupt request occurs.
(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
(4) If a INT0 interrupt occurs, start supplying the BCLK from 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.
from X
and enter wait mode again.
the INT0 interrupt, and switch the system clock to X
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IN
“H”
“L”
CIN.
High-speed
and enter wait mode. In this instance, enable the timer A2 interrupt and the INT0 interrupt.
At this time, count the clock within the routine that handles the timer A2 interrupts
(1) Shift to low-speed mode
Low-speed
(2) Stop X
________
(3) Timer A2 interrupt
IN
IN
Low-speed
to X
CIN
CIN
to get low-speed mode.
to serve as the timer count source. As interrupts
IN
Low-speed
.
CIN
3. Controlling Power Applications
. Start the X
(4) INT
Low-speed
IN
0
interrupt
oscillation within
High-speed
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