Software and EMC

I know of two excellent articles describing the impact of software on EMC.  The main impacts are related to making the design robust and resiliant to electromagnetic disturbances to make sure the product can pass susceptibility tests.  Both articles also mention how software can affect the emissions profile of a product as well.  The latter article contains some practical steps that can be taken in software to minimize emissions [2].  To summarize these techniques:

• Drive output clocks with spread spectrum
• Turn off peripherals and circuitry inside the processor that is not being used
• Get the lowest feasible drive strengths for microprocessor IO from your SI engineer
• Minimize communications to only necessary level - don't define protocols that have a lot of redundant, unnecessary communciations
• Optimize software architecture to minimize idle loops and allow power down between bursts of activity and also possibly reduce clock frequency

[1] O'Hara, Martin. September 2007. "The EMC Impact of Embedded Software." Conformity.

[2] Brotz, Joseph. May 28, 2008. "Software Techniques for Comprehensive EMC Testing of Embedded Systems." Emedded.com.