h8s-2138 Renesas Electronics Corporation., h8s-2138 Datasheet - Page 425

• Manufacturer Part Number: h8s-2138
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

14.1
The H8S/2138 Group and H8S/2134 Group have an on-chip watchdog timer with two channels
(WDT0, WDT1) for monitoring system operation. The WDT outputs an overflow signal if a
system crash prevents the CPU from writing to the timer counter, allowing it to overflow. At the
same time, the WDT can also generate an internal reset signal or internal NMI interrupt signal.
When this watchdog function is not needed, the WDT can be used as an interval timer. In interval
timer mode, an interval timer interrupt is generated each time the counter overflows.
14.1.1
WDT features are listed below.
Switchable between watchdog timer mode and interval timer mode
Internal reset or internal interrupt generated when the timer counter overflows
Choice of 8 (WDT0) or 16 (WDT1) counter input clocks
WOVI interrupt generation in interval timer mode
Choice of internal reset or NMI interrupt generation in watchdog timer mode
Maximum WDT interval: system clock period
Subclock can be selected for the WDT1 input counter
Maximum interval when the subclock is selected: subclock period 256
Overview
Features
Section 14 Watchdog Timer (WDT)
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Rev. 4.00 Jun 06, 2006 page 371 of 1004
Section 14 Watchdog Timer (WDT)
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REJ09B0301-0400
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