> I am using external 13 bit ADC witch originally won't 
> necessary to go that high resolution "not under my control" 
> now the result I am getting is noisy numbers are going high 
> and low. what I did is reading it 10 times then I add them 
> together then divide it by 10.
> It helps but one of our engineer asked me to add software low 
> pass filter witch I am familiar with it. Reading 10 times 
> values are up to 15 point different. 
> My question is do you have any experience or know how 
> software LPF work?
> any link or info will appreciate. I searched piclist.com not 
> enough info I found to understand what to do.

Did you find:
http://www.piclist.com/techref/microchip/math/filter.htm?key=filter&from=

http://www.piclist.com/techref/logic/dsps.htm

http://www.piclist.com/techref/microchip/dsp/iir-24b-256s-tk.htm?key=filter+
low+pass

But the best explanation of filters, taking them from analog to digital,
that I have seen is hidden away at
http://www.piclist.com/techref/new/letter/news0405.htm And is from an old
'78 Byte magazine. Many people will tell you that the code there is poor and
many better ways exist, but I can understand that code and I can't
understand the others, so if you are only as smart as I, you will be ok with
that page. <grin>

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