June 2014

DocID5833 Rev 2

1/19

AN1015

Application note

Software techniques for improving microcontrollers EMC performance

Introduction

A major contributor to improved EMC performance in microcontroller-based electronics

systems is the design of hardened software.

Problems induced by EMC disturbances need to be considered as early as possible in the

design phase. EMC-oriented software increases the security and the reliability of your

application. EMC-hardened software is inexpensive to implement, improves the final goods

immunity performance and saves hardware and development costs. You should consider

EMC disturbances to analog or digital data just like any other application parameter.

Examples of problems induced by EMC disturbances:

 Microcontroller not responding

 Program Counter runaway

 Execution of unexpected instructions

 Bad address pointing

 Bad execution of subroutines

 Parasitic reset and/or parasitic interrupts

 Corruption of IP configuration

 I/O deprogramming

Examples of consequences of failing software:

 Unexpected response of product

 Loss of context

 Unexpected branch in process

 Loss of interrupts

 Loss of data integrity

 Corrupted reading of input values.

This application note deals with two categories of software techniques, namely:

 Preventive techniques: these can be implemented in existing designs, their purpose is to

improve product robustness.

 Auto-recovery techniques: when a runaway condition is detected, a recovery subroutine

is used to take the decision to execute fail-safe routines, optionally sending a warning and

then automatically returning back to normal operations (this operation may be absolutely

transparent to the user of the application).

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