Section 11 8-Bit Timer (Tmr); Features - Renesas H8S/2437 Hardware Manual

This LSI has an on-chip 2-system 8-bit timer module (TMR0 and TMR1) with two channels
operating on the basis of an 8-bit counter. In addition to external event counting, the 8-bit timer
module can be used as a multifunction timer in a variety of applications, such as generation of
counter reset, interrupt requests, and pulse output with an arbitrary duty cycle using a compare-
match signal with two registers.
This LSI also has a similar on-chip 2-system 8-bit timer module (TMRY and TMRX) with two
channels.
11.1

Features

• Selection of clock sources
TMR0, TMR1: The counter input clock can be selected from six internal clocks and an
external clock
TMRY, TMRX: The counter input clock can be selected from three internal clocks and an
external clock
• Selection of three ways to clear the counters
The counters can be cleared on compare-match A or compare-match 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.
• Cascading of two systems
Cascading of TMR0 and TMR1:
Operation as a 16-bit timer can be performed using the TMR0 as the upper half and TMR1 as
the lower half (16-bit count mode).
The TMR1 can be used to count TMR0 compare-match occurrences (compare-match count
mode).
Cascading of TMRY and TMRX:
Operation as a 16-bit timer can be performed using the TMRY as the upper half and TMRX as
the lower half (16-bit count mode).
The TMRX can be used to count TMRY compare-match occurrences (compare-match count
mode).
• Multiple interrupt sources for each channel
TMR0, TMR1, and TMRY: Three types of interrupts: Compare-match A, compare-match B,
and overflow
TIMH261A_000020020300

Section 11 8-Bit Timer (TMR)

Rev. 1.00, 09/03, page 267 of 704