M38002M4 Datasheet, PDF (59/173 Pages) Mitsubishi Electric Semiconductor – 8-BIT SINGLE-CHIP MICROCOMPUTER

APPLICATION
2.2 Timer
2.2.3 Timer application examples
(1) Basic functions and uses
[Function 1] Control of Event interval (Timer X, Timer Y, Timer 1, Timer 2)
The Timer count stop bit is set to “0” after setting a count value to a timer. Then a timer interrupt
request occurs after a certain period.
[Use] • Generation of an output signal timing
• Generation of a waiting time
[Function 2] Control of Cyclic operation (Timer X, Timer Y, Timer 1, Timer 2)
The value of a timer latch is automatically written to a corresponding timer every time a timer
underflows, and each cyclic timer interrupt request occurs.
[Use] • Generation of cyclic interrupts
• Clock function (measurement of 250m second)
• Control of a main routine cycle
Application example 1
[Function 3] Output of Rectangular waveform (Timer X, Timer Y)
The output level of the CNTR pin is inverted every time a timer underflows (Pulse output mode).
[Use] • A piezoelectric buzzer output Application example 2
• Generation of the remote-control carrier waveforms
[Function 4] Count of External pulse (Timer X, Timer Y)
External pulses input to the CNTR pin are selected as a timer count source (Event counter
mode).
[Use]
• Measurement of frequency Application example 3
• Division of external pulses.
• Generation of interrupts in a cycle based on an external pulse.
(count of a reel pulse)
[Function 5] Measurement of External pulse width (Timer X, Timer Y)
The “H” or “L” level width of external pulses input to CNTR pin is measured (Pulse width
measurement mode).
[Use] • Measurement of external pulse frequency (Measurement of pulse width of FG pulse^V gener-
ated by motor) Application example 4
• Measurement of external pulse duty (when the frequency is fixed)
VFG pulse : Pulse used for detecting the motor speed to control the motor speed.
3800 GROUP USER’S MANUAL
2-11