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Revision 1.00

10 - 13

AS1916 - AS1918

Data Sheet - A p p l i c a t i o n I n f o r m a t i o n

Figure 13 shows a flowchart where the input/output driving the watchdog is set high at the beginning of the routine, set

low at the beginning of every subroutine, then set high again when the routine returns to the beginning. If the routine

should hang in a subroutine, the problem would quickly be corrected, since the I/O is continually set low and the watch-

dog timer is allowed to time out, causing a reset or interrupt to be issued (see Watchdog Input Current on page 9). This

method results in higher averaged WDI input current over time than a case where WDI is held low for the majority

(87.5%) of the timeout period and periodically pulsing it low-high-low.

Figure 13. Example Watchdog Programming Flowchart

Start

Set WDI

High

Subroutine or

Program Loop

Set WDI Low

Return

Program

Code