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10.1
Overview
The H8/3067 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 (TCNT) and two 8-
bit time constant registers (TCORA and TCORB) that are constantly compared with the TCNT
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.
• Twelve interrupt sources
There are twelve interrupt sources: four compare match sources, four compare match/input
capture sources, four overflow sources.
Section 10 8-Bit Timers
Section 10 8-Bit Timers
Rev. 4.00 Jan 26, 2006 page 397 of 938
REJ09B0276-0400
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