Decoder Performance on Dirty Track

[davidalevans]

Hi All, I have successfully made a function decoder and I am very pleased with the results – Thank you Paul for sharing your knowledge with us all! I am no expert in electronics or PIC programming but I have decided to sit down and understand the design and the code. One thing that has puzzled me when looking at the decoder is that on the main site it mentions the functionality the decoders perform and one of them being: "Sensitive input will decode packets even on very dirty track far beyond the NMRA spec.". Can you help me to understand how? ….Is this because you use the PIC comparator instead of an input pin change to be either polled or used as an interrupt?

Help with this would be greatly appreciated
Thanks,
David

[Paul Harman]

Yes, use of an analogue comparator allows the accurate determination of the voltage across the rails however small it is - even a few millivolts, most decoders require the voltage to be at least 5V under all circumstances.

[davidalevans]

Thank you Paul for your response. This is very helpful.