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Section 9 Timers
Rev. 6.00 Sep 12, 2006 page 270 of 526
REJ09B0326-0600
9.6 Watchdog
Timer
9.6.1 Overview
The watchdog timer has an 8-bit counter that is incremented by an input clock. If a system
runaway allows the counter value to overflow before being rewritten, the watchdog timer can reset
the chip internally.
Features
Features of the watchdog timer are given below.
•
Incremented by internal clock source (
φ
/8192).
•
A reset signal is generated when the counter overflows. The overflow period can be set from 1
to 256 times 8192/
φ
(from approximately 2 ms to 500 ms when
φ
= 4.19 MHz).
Block Diagram
Figure 9.35 shows a block diagram of the watchdog timer.
PSS
TCSRW
TCW
φ
/8192
Legend:
TCSRW:
TCW:
PSS:
Timer control/status register W
Timer counter W
Prescaler S
φ
Internal data bus
Internal reset
signal
Figure 9.35 Block Diagram of Watchdog Timer
Содержание F-ZTAT H8/3642A Series
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Страница 188: ...Section 6 ROM Rev 6 00 Sep 12 2006 page 166 of 526 REJ09B0326 0600 ...
Страница 190: ...Section 7 RAM Rev 6 00 Sep 12 2006 page 168 of 526 REJ09B0326 0600 ...
Страница 298: ...Section 9 Timers Rev 6 00 Sep 12 2006 page 276 of 526 REJ09B0326 0600 ...
Страница 378: ...Section 12 A D Converter Rev 6 00 Sep 12 2006 page 356 of 526 REJ09B0326 0600 ...
Страница 446: ...Section 13 Electrical Characteristics Rev 6 00 Sep 12 2006 page 424 of 526 REJ09B0326 0600 ...