HD64F2149YV datasheet(337/1075 Pages) RENESAS

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Section 11 16-Bit Free-Running Timer

Rev. 3.00 Jan 18, 2006 page 309 of 1044

REJ09B0280-0300

Section 11 16-Bit Free-Running Timer

11.1

Overview

The H8S/2169 or H8S/2149 has a single-channel on-chip 16-bit free-running timer (FRT) module

that uses a 16-bit free-running counter as a time base. Applications of the FRT module include

rectangular-wave output (up to two independent waveforms), input pulse width measurement, and

measurement of external clock periods.

11.1.1

Features

The features of the free-running timer module are listed below.

• Selection of four clock sources

 The free-running counter can be driven by an internal clock source (φ/2, φ/8, or φ/32), or an

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

• Two independent comparators

 Each comparator can generate an independent waveform.

• Four input capture channels

 The current count can be captured on the rising or falling edge (selectable) of an input

signal.

 The four input capture registers can be used separately, or in a buffer mode.

• Counter can be cleared under program control

 The free-running counters can be cleared on compare-match A.

• Seven independent interrupts

 Two compare-match interrupts, four input capture interrupts, and one overflow interrupt

can be requested independently.

• Special functions provided by automatic addition function

 The contents of OCRAR and OCRAF can be added to the contents of OCRA

automatically, enabling a periodic waveform to be generated without software intervention.

 The contents of ICRD can be added automatically to the contents of OCRDM × 2, enabling

input capture operations in this interval to be restricted.

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