November 2011

Doc ID 2476 Rev 2

1/11

AN421

Application note

Stack overflow detection using the ST9 timer/watchdog

1

Introduction

In real time applications, implementation of software protection is not always easy, but it is

needed to reach a high level of security against software malfunction. This is particularly

true for on-board applications in noisy environments, such as automotive, power meter or

industrial applications.

To help avoid un-controlled operations and damage to real time systems due to any possible

disturbance of the ST9 microcontroller core and I/O ports, a special peripheral acting as a

watchdog is available on all ST9 family members: the Timer/Watchdog.

The periodic restarting of the Timer/Watchdog by the application software, associated with

the automatic detection of any stack overflow, provide enhanced protection to real time

application software.

This application note shows how to detect stack overflow by using the Timer/Watchdog in

watchdog mode.

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