Datasheet

MAX6361–MAX6364
Watchdog Software Considerations
(MAX6362 Only)
To help the watchdog timer monitor software execution
more closely, set and reset the watchdog input at dif-
ferent points in the program, rather than “pulsing” the
watchdog input low-high-low. This technique avoids a
“stuck” loop, in which the watchdog timer would contin-
ue to be reset within the loop, keeping the watchdog
from timing out. Figure 2 shows an example of a flow
diagram where the I/O driving the WDI is set low at the
beginning of the program, set high at the beginning of
every subroutine or loop, then set low again when the
program returns to the beginning. If the program
should “hang” in any subroutine, the problem would
quickly be corrected, since the I/O is continually set low
and the watchdog timer is allowed to time out, trigger-
ing a reset.
SOT23, Low-Power µP Supervisory Circuits
with Battery Backup
8 _______________________________________________________________________________________
START
SET
WDI
LOW
RETURN
END
SUBROUTINE
OR PROGRAM LOOP
SET WDI
HIGH
Figure 2. Watchdog Flow Diagram