Section 9 Timers; Overview - Renesas F-ZTAT H8 Series Hardware Manual

9.1

Overview

The H8/3857 Group is provided with four timers (timers A, B, C, and F), and the H8/3854 Group
with three (timers A, B, and F). The H8/3857F and H8/3854F also have an on-chip watchdog
timer for flash memory programming control.
Table 9.1 outlines the functions of timers A, B, C, F, and the watchdog timer.
Table 9.1 Timer Functions
Name Functions
• 8-bit timer
Timer A
• Interval timer
• 8-bit timer
• Time base
• 8-bit timer
• Clock output
• 8-bit timer
Timer B
• Interval timer
• Event counter
• 8-bit timer
1
Timer C*
• Interval timer
• Event counter
• Choice of up- or down-
counting
• 16-bit timer
Timer F
• Event counter
• Can be used as two
independent 8-bit
timers
• Output compare
• Generates reset signal
Watchdog
2
on overflow of 8-bit
timer*
counter
Notes: 1. Timer C is a function of the H8/3857 Group only, and is not provided in the H8/3854
Group.
2. The watchdog timer is used by the flash memory programming control program.

Section 9 Timers

Internal Clock
φ/8 to φ/8192
(8 choices)
φ
/128
W
(choice of 4
overflow periods)
φ/4 to φ/32,
φ /4 to φ
/32
W W
(8 choices)
φ/4 to φ/8192
(7 choices)
φ/4 to φ/8192,
φ
/4 (7 choices)
W
φ/2 to φ/32
(4 choices)
φ/64 to φ/8192
(8 choices)
Event Waveform
Input Pin Output Pin Remarks
⎯ ⎯
⎯ ⎯
⎯
TMOW
⎯
TMIB
⎯
TMIC
TMIF TMOFL
TMOFH
⎯ ⎯
Rev.3.00 Jul. 19, 2007 page 209 of 532
9. Timers
Counting
direction can be
controlled by
software or
hardware
Provided only in
H8/3857F and
H8/3854F
REJ09B0397-0300