HD64F2149 Datasheet, PDF (363/1035 Pages) Renesas Technology Corp – Hitachi 16-Bit Single-Chip Microcomputer

Section 12 8-Bit Timers
12.1 Overview
The H8S/2169 or H8S/2149 includes an 8-bit timer module with two channels (TMR0 and
TMR1). Each channel has an 8-bit counter (TCNT) and two time constant registers (TCORA and
TCORB) that are constantly compared with the TCNT value to detect compare-matches. The 8-bit
timer module can be used as a multifunction timer in a variety of applications, such as generation
of a rectangular-wave output with an arbitrary duty cycle.
The H8S/2169 or H8S/2149 also has two similar 8-bit timer channels (TMRX and TMRY). These
channels can be used in a connected configuration using the timer connection function. TMRX
and TMRY have greater input/output and interrupt function related restrictions than TMR0 and
TMR1.
12.1.1 Features
• Selection of clock sources
 TMR0, TMR1: The counter input clock can be selected from six internal clocks and an
external clock (enabling use as an external event counter).
 TMRX, TMRY: The counter input clock can be selected from three internal clocks and an
external clock (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 by an external reset signal.
• 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 be used for various applications, such as the generation of
pulse output or PWM output with an arbitrary duty cycle.
(Note: TMRY does not have a timer output pin.)
• Cascading of the two channels (TMR0, TMR1)
 Operation as a 16-bit timer can be performed using channel 0 as the upper half and channel
1 as the lower half (16-bit count mode).
 Channel 1 can be used to count channel 0 compare-match occurrences (compare-match
count mode).
• Multiple interrupt sources for each channel
 TMR0, TMR1, TMRY: Two compare-match interrupts and one overflow interrupt can be
requested independently.
 TMRX: One input capture source is available.
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