Timer A; Overview - Renesas H8/3847R Series Hardware Manual

8-bit single-chip microcomputer super low power

Table of Contents

Section 9 Timers

• 16-bit counter

• Also usable as two

independent 8-bit

• Counts events

asynchronous to φ and

Timer A

Timer A is an 8-bit timer with interval timing and real-time clock time-base functions. The clock

time-base function is available when a 32.768 kHz crystal oscillator is connected. A clock signal

divided from 32.768 kHz, from 38.4 kHz (if a 38.4 kHz crystal oscillator is connected), or from

the system clock, can be output at the TMOW pin.

Features of timer A are given below.

• Choice of eight internal clock sources (φ/8192, φ/4096, φ/2048, φ/512, φ/256, φ/128, φ/32,

• Choice of four overflow periods (1 s, 0.5 s, 0.25 s, 31.25 ms) when timer A is used as a clock

time base (using a 32.768 kHz crystal oscillator).

• An interrupt is requested when the counter overflows.

• Any of nine clock signals can be output at the TMOW pin: 32.768 kHz divided by 32, 16, 8, or

4 (1 kHz, 2 kHz, 4 kHz, 8 kHz, 32.768 kHz) or 38.4 kHz divided by 32, 16, 8, or 4 (1.2 kHz,

2.4 kHz, 4.8 kHz, 9.6 kHz, 38.4 kHz), and the system clock divided by 32, 16, 8, or 4.

• Use of module standby mode enables this module to be placed in standby mode independently

when not used.

Rev. 6.00 Aug 04, 2006 page 258 of 680

REJ09B0145-0600

Internal Clock

Output Pin Remarks