Renesas H8/38024 Series, Hardware Manual

Page: 268 / 661

Rev. 6.00, 08/04, page 238 of 628
Name Functions Internal Clock
Event
Input Pin Waveform
Output Pin
Remarks
Asynchro-
nous event
counter
•
16-bit counter
•
Also usable as two
independent 8-bit
counters
•
Counts events
asynchronous to
φ
and
φ
w
•
Can count asynchronous
events (rising/falling/both
edges) independ-ently of
the MCU's internal clock
φ
/2 to
φ
/8
(3 choices)
AEVL
AEVH
IRQAEC —
Note:
*
The watchdog timer functions differently on the H8/38024, H8/38024S, H8/38024F-ZTAT
Group and H8/38124 Group. See section 9.6, Watchdog Timer, for details.
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.
Features
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,
φ
/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.
•
Use of module standby mode enables this module to be placed in standby mode independently
when not used.