MAX6317 MAXIM [Maxim Integrated Products], MAX6317 Datasheet - Page 11

• Manufacturer Part Number: MAX6317
• Description: 5-Pin uP Supervisory Circuits with Watchdog and Manual Reset
• Manufacturer: MAXIM [Maxim Integrated Products]

Figure 10 shows an example of a flow diagram where
the I/O driving the watchdog input is set high at the
beginning of the program, set low at the end of every
subroutine or loop, then set high again when the pro-
gram returns to the beginning. If the program should
hang in any subroutine, the problem would be quickly
corrected, since the I/O is continually set low and the
watchdog timer is allowed to time out, causing a reset
or interrupt to be issued. As described in the Watchdog
Input Current section, this scheme results in higher time
average WDI current than does leaving WDI low for the
majority of the timeout period and periodically pulsing it
low-high-low.
__________________Pin Configurations
TOP VIEW
RESET
RESET
RESET
GND
GND
MR
1
2
3
1
2
3
MAX6316
MAX6320
MAX6318
MAX6321
SOT23
SOT23
______________________________________________________________________________________
5 V
4
5 V
4
WDI
WDI
CC
CC
RESET
RESET
RESET
GND
GND
MR
5-Pin µP Supervisory Circuits with
1
2
3
1
2
3
MAX6317
MAX6319
MAX6322
SOT23
SOT23
Watchdog and Manual Reset
5 V
4
5 V
4
WDI
MR
CC
CC
Figure 10. Watchdog Flow Diagram
MANUAL
RESET
V
IN
Typical Operating Circuit
SUBROUTINE OR
PROGRAM LOOP
SET WDI LOW
PROGRAM
SET WDI
RETURN
START
CODE
HIGH
MR
MAX6316
GND
V
CC
RESET
WDI
POSSIBLE
INFINITE LOOP PATH
RESET
I/O
GND
V
µP
CC
11