H8SLASH3028F datasheet(403/923 Pages) RENESAS

403 / 923 page

Rev. 2.00, 09/03, page 373 of 890

Section 10 8-Bit Timers

10.1

Overview

The H8/3028 Group has a built-in 8-bit timer module with four channels (TMR0, TMR1, TMR2,

and TMR3), based on 8-bit counters. Each channel has an 8-bit timer counter (8TCNT) and two

8-bit time constant registers (TCORA and TCORB) that are constantly compared with the 8TCNT

value to detect compare match events. The timers can be used as multifunctional timers in a

variety of applications, including the generation of a rectangular-wave output with an arbitrary

duty cycle.

10.1.1

Features

The features of the 8-bit timer module are listed below.

• Selection of four clock sources

The counters can be driven by one of three internal clock signals (

φ/8, φ/64, or φ/8192) or an

external clock input (enabling use as an external event counter).

• Selection of three ways to clear the counters

The counters can be cleared on compare match A or B, or input capture B.

• Timer output controlled by two compare match signals

The timer output signal in each channel is controlled by two independent compare match

signals, enabling the timer to generate output waveforms with an arbitrary duty cycle or PWM

output.

• A/D converter can be activated by a compare match

• Two channels can be cascaded

 Channels 0 and 1 can be operated as the upper and lower halves of a 16-bit timer (16-bit

count mode).

 Channels 2 and 3 can be operated as the upper and lower halves of a 16-bit timer (16-bit

count mode).

 Channel 1 can count channel 0 compare match events (compare match count mode).

 Channel 3 can count channel 2 compare match events (compare match count mode).

• Input capture function can be set

8-bit or 16-bit input capture operation is available.

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