M16CSLASH62M datasheet(521/615 Pages) RENESAS

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Timer A Applications

Mitsubishi microcomputers

M16C / 62A Group

SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

2-204

3.4 Buzzer Output

Overview

Specifications

Operation

Figure 3.4.1. Operation timing of buzzer output

“0”

“1”

“0”

“1”

Timer A0

overflow timing

Count start flag

Pulse output

function select bit

P70 output

“0”

“1”

High-impedance

(1) Start count

(2) Buzzer output ON

(3) Buzzer output OFF

The timer mode is used to make the buzzer ring. Figure 3.4.1 shows the operation timing, and

Figure 3.4.2 shows the set-up procedure.

Use the following peripheral function:

• The pulse-outputting function in timer mode of timer A.

(1) Sound a 2-kHz buzz beep by use of timer A0.

(2) Effect pull-up in the relevant port by use of a pull-up resistor. When the buzzer is off, set the

port high-impedance, and stabilize the potential resulting from pulling up.

(3) Connect a 16-MHz oscillator to XIN.

(1) The microcomputer begins performing a count on timer A0. Timer A0 has disabled interrupts.

(2) The microcomputer begins pulse output by setting the pulse output function select bit to

“Pulse output effected”. P70 changes into TA0OUT pin and outputs 2-kHz pulses.

(3) The microcomputer stops outputting pulses by setting the pulse output function select bit to

“Pulse output not effected”. P70 goes to an input pin, and the output from the pin becomes

high-impedance.

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