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9.2 Timer A
9.2.1 Overview
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.
1.
Features
Features of timer A are given below.
•
Choice of eight internal clock sources (ø/8192, ø/4096, ø/2048, ø/512, ø/256, ø/128, ø/32, ø/8).
•
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) or 38.4 kHz divided by 32, 16, 8, or 4 (1.2 kHz, 2.4 kHz, 4.8
kHz, 9.6 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.
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