EMC techniques for microprocessor software

As many design engineers have found, embedding microcontrollers into products provides extra features and functionality, but also introduces a new set of EMC problems, including susceptibility. Microcontroller based equipment is particularly vulnerable to electrical transients such as electrostatic discharge (ESD), electrical fast transient bursts (EFT), high energy surges and supply dips, interruptions and variations. Hardware countermeasures should always be the first line of defence, to achieve any chance of immunity to transient phenomena. However, there are also defensive measures that may be applied in software. Through experience gained on a variety of microcontroller based products, the author has compiled a simple strategy for hardening microcontroller based systems. It is assumed that general EMC principles and immunising strategies are known and implemented as far as is practically appropriate, and these measures are not restated