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M30245 Group
3.3 Buzzer Output
The timer mode is used to make the buzzer ring. Figure 3.3.1 shows the operation timing, and
Overview
Figure 3.3.2 shows the set-up procedure.
Use the following peripheral function:
• The pulse-outputting function in timer mode of timer A.
Specifications
(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 X
Operation
(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". P7
(3) The microcomputer stops outputting pulses by setting the pulse output function select bit to
"Pulse output not effected". P7
high-impedance.
Timer A0
overflow timing
"1"
Count start flag
"0"
"1"
Pulse output
function select bit
"0"
"1"
P7
output
0
"0"
Figure 3.3.1. Operation timing of buzzer output
Rev.2.00 Oct 16, 2006
REJ09B0340-0200
changes into TA0
0
(1) Start count
High-impedance
page 303 of 354
.
IN
pin and outputs 2-kHz pulses.
OUT
goes to an input pin, and the output from the pin becomes
0
(2) Buzzer output ON
3. Timer A Applications
(3) Buzzer output OFF
High-impedance
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