Datasheet

Section 13 8-Bit Timers (TMR)
R01UH0309EJ0500 Rev. 5.00 Page 821 of 1408
Sep 24, 2012
H8S/2456, H8S/2456R, H8S/2454 Group
Section 13 8-Bit Timers (TMR)
This LSI has an on-chip 8-bit timer module with two channels operating on the basis of an 8-bit
counter. The 8-bit timer module can be used to count external events and 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.
13.1 Features
• Selection of seven clock sources
The counters can be driven by one of six internal clock signals (φ/2, φ/8, φ/32, φ/64, φ/1024, or
φ/8192) or an external clock input
• 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 (rising
edge, rising and falling edges, falling edge, low level, or high level)
• Timer output control by a combination of two compare match signals
The timer output signal in each channel is controlled by a combination of two independent
compare match signals, enabling the timer to generate output waveforms with an arbitrary duty
cycle or PWM output
• Provision for cascading of two channels (TMR_0 and TMR_1)
Operation as a 16-bit timer is possible, using TMR_0 for the upper 8 bits and TMR_1 for the
lower 8 bits (16-bit count mode)
TMR_1 can be used to count TMR_0 compare matches (compare match count mode)
• Three independent interrupts
Compare match A and B and overflow interrupts can be requested independently
• A/D converter conversion start trigger can be generated