Section 9 Timers
9.1 Overview
The H8/3864 Series provides six timers: timers A, C, F, G, and a watchdog timer, and an
asynchronous event counter. The functions of these timers are outlined in table 9-1.
Table 9-1 Timer Functions
Event Waveform
Name
Functions
Internal Clock
Input Pin
Output Pin
Remarks
Timer A
• 8-bit interval timer
ø/8 to ø/8192
—
—
• Interval function
(8 choices)
• Time base
ø
w
/128 (choice of
4 overflow periods)
• Clock output
ø/4 to ø/32
—
TMOW
ø
w,
ø
w
/4 to ø
w
/32
(9 choices)
Timer C
• 8-bit timer
ø/4 to ø/8192, ø
w
/4 TMIC
—
Up-count/
• Interval function
(7 choices)
down-count
• Event counting
controllable by
function
software or
• Up-count/down-
hardware
count selectable
Timer F
• 16-bit timer
ø/4 to ø/32, ø
w
/4 TMIF
TMOFL
• Event counting
(4 choices)
TMOFH
function
• Also usable as
two independent
8-bit timers
• Output compare
output function
Timer G
• 8-bit timer
ø/2 to ø/64, ø
w
/4
TMIG
—
• Counter
• Input capture
(4 choices)
clearing
function
option
• Interval function
• Built-in
capture input
signal noise
canceler
Watchdog • Reset signal
ø/8192
—
—
timer
generated when
ø
w
/32
8-bit counter
overflows
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