M16CSLASH62M datasheet(323/615 Pages) RENESAS

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Timer A

Mitsubishi microcomputers

M16C / 62A Group

SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

2-6

2.2.1 Overview of the timer A usage

Timer A is a 16-bit timer. The following is an overview of the timer A usage.

(1) Mode

Timer A operates in one of the four modes:

(a) Timer mode

In this mode, the internal count source is counted. Two functions can be selected: the pulse output

function that reverses output from a port every time an overflow occurs, or the gate function which

controls the count start/stop according to the input signal from a port.

• Timer mode operation ............................................................................................................. P2-12

• Timer mode, gate function operation ....................................................................................... P2-14

• Timer mode, pulse output function operation .......................................................................... P2-16

(b) Event counter mode

This mode counts the pulses from the outside and the number of overflows in other timers. The free-

run type, in which nothing is reloaded from the reload register, can be selected when an underflow

occurs. The pulse output function can also be selected. Please refer to the timer mode explanation

for details, as the operation is identical.

• Event counter mode operation ................................................................................................ P2-18

• Event counter mode, free run type operation .......................................................................... P2-20

Furthermore, Timer A has a 2-phase pulse signal processing function which generates an up count

or down count in the event counter mode, depending on the phase of the two input signals.

• Operation of the 2-phase pulse signal processing function in normal event counter mode .... P2-22

• Operation of the 2-phase pulse signal processing function in 4-multiplication mode .............. P2-24

In this mode, the timer is started by the trigger and stops when the timer goes to “0”. The trigger can

be selected from the following 3 types: an external input signal, an overflow of the timer, or a software

trigger. The pulse output function can also be selected. Please refer to the timer mode explanation

for details, as the operation is identical.

• Operation in one-shot timer mode effected by software .......................................................... P2-26

• Operation in one-shot timer mode effected by an external trigger .......................................... P2-28

(d) Pulse width modulation (PWM) mode

In this mode, the arbitrary pulses are successively output. Either a 16-bit fixed-period PWM mode or

8-bit variable-period mode can be selected. The trigger for initiating output can also be selected.

Please refer to the one-shot timer mode explanation for details, as the operation is identical.

• 16-bit PWM mode operation .................................................................................................... P2-30

• 8-bit PWM mode operation ...................................................................................................... P2-32

2.2 Timer A Usage

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