M16C62_M Datasheet, PDF (521/615 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/60 SERIES

Timer A Applications
Mitsubishi microcomputers
M16C / 62A Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
3.4 Buzzer Output
Overview 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.
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 XIN.
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”. 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.
(1) Start count
(2) Buzzer output ON
Timer A0
overflow timing
“1”
Count start flag
“0”
Pulse output
“1”
function select bit
“0”
“1”
P70 output
“0”
High-impedance
Figure 3.4.1. Operation timing of buzzer output
2-204
(3) Buzzer output OFF
High-impedance