Renesas H8S/2158, User Manual

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Section 13 8-Bit Timer (TMR)
Rev. 3.00 Jan 25, 2006 page 315 of 872
REJ09B0286-0300
Section 13 8-Bit Timer (TMR)
This LSI has an on-chip 8-bit timer module (TMR_0 and TMR_1) with two channels operating on
the basis of an 8-bit counter. 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 8-bit timer module (TMR_Y and TMR_X) with two channels,
which can be used through connection to the timer connection.
13.1 Features
•
Selection of clock sources
TMR_0, TMR_1: The counter input clock can be selected from six internal clocks and an
external clock
TMR_Y, TMR_X: 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 channels

Cascading of TMR_0 and TMR_1
Operation as a 16-bit timer can be performed using TMR_0 as the upper half and TMR_1
as the lower half (16-bit count mode).
TMR_1 can be used to count TMR_0 compare-match occurrences (compare-match count
mode).
•
Multiple interrupt sources for each channel
TMR_0, TMR_1, and TMR_Y: Three types of interrupts: Compare-match A, compare-
match B, and overflow
TMR_X: Four types of interrupts: Compare-match A, compare-
match B, overflow, and input capture
Figures 13.1 and 13.2 show block diagrams of 8-bit timers.
TIMH261A_000020020300