Lpc2000

Huber Martin wrote:

> 
>
>________________________________
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>Von: Karl Olsen [mailto:kro@...] 
>Gesendet: Montag, 6. Februar 2006 10:30
>An: lpc2000@yahoogroups.com
>Betreff: [lpc2000] Re: Rise and fall time of capture inputs
>
> 
>I don't think it is possible to miss a capture event because of slow 
>rise/fall times.  You get a capture event when the input is e.g. low at 
>one pclk edge and high at the next, and this will happen at least once 
>no matter how slow the input rises.
>
>[MEH]  This is an interesting fact. Thank you.
> 
>Another problem might be noise on the input so that you get multiple 
>rise and fall events around the switching level.  The datasheets say 
>that there is a hysteresis of typically 0.4V on all standard port pins 
>and some more on the I2C pins, so this should filter most noise.
>
>[MEH]  That's the reason my signal is so slow. It's filtered with an
>EMI-Filter, so no flicker should be on the line.
>
>  
>
How stable and quiet is your ground between the two units?  Ground shift 
can also occur between unit introducing "noise"?  Just a FWIW to name 
another thing that has bitten me in the past...

Regards,

TomW

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-- 
Tom Walsh - WN3L - Embedded Systems Consultant
http://openhardware.net, http://cyberiansoftware.com
"Windows? No thanks, I have work to do..."
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