Timers; Overview - Hitachi H8/3937 Series Hardware Manual

9.1

Overview

The H8/3937 Series and H8/3937R Series provide five timers: timers A, C, F, G, and a watchdog
timer. The functions of these timers are outlined in table 9-1.
Table 9-1 Timer Functions
Name Functions
• 8-bit interval timer
Timer A
• Interval function
• Time base
• Clock output
• 8-bit timer
Timer C
• Interval function
• Event counting function
• Up-count/down-count
selectable
• 16-bit timer
Timer F
• Event counting function
• Also usable as two
independent 8-bit timers
• Output compare output
function
• 8-bit timer
Timer G
• Input capture function
• Interval function
• Reset signal generated
Watchdog
timer
when 8-bit counter
overflows
Section 9 Timers
Internal Clock
ø/8 to ø/8192
(8 choices)
ø /128 (choice of
W
4 overflow periods)
ø/4 to ø/32 ø , ø
W
to ø /32 (9 choices)
W
ø/4 to ø/8192, ø
W
(7 choices)
ø/4 to ø/32, ø /4
W
(4 choices)
ø/2 to ø/64, ø /4
W
(4 choices)
ø/8192
øw/32
Event Waveform
Input Pin Output Pin Remarks
— —
/4 — TMOW
W
/4 TMIC —
TMIF TMOFL
TMOFH
TMIG —
— —
Up- count/
down-count
controllable by
software or
hardware
Counter
clearing option
Built-in capture
input signal
noise canceler
179