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Hi all,
At the moment I am trying to provide a negative value to a comparator positive input pin, so the comparator output will be triggered high once a negative voltage goes lower than this defined threshold.
Unfortunatelly it looks like the PSoC does not accept a negative signal. I have checked this with scope and anything that goes below 0 Volts just disappears from the input signal.
Am I doing somethign wrong or this is, in fact, the way it is?
Thanks.
Solved! Go to Solution.
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PSoC 5LP
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No input signal may be lower than GND on a PSoC. Use an R-ladder to shift the signal into positve Voltage.
Bob
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No input signal may be lower than GND on a PSoC. Use an R-ladder to shift the signal into positve Voltage.
Bob
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@Dana
The 12123.xls does not calculate R1 to R3 and a schematic would be helpful.
Bob
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The Excel sheet does work.
In the zip file is a txt file with URL to the original article, and how to install
the Excel "Solver", an iterative engine to generate the solution.
I changed the zip, added the article PDF and pics to make life easy. Missing last pic
but it is not significant.
Regards, Dana.
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Remeber that when using a resistor dvider with one end attached to VCC. The value to the PSoC is "SCALED" and "SHIFED"
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Hi Dana and Bob, thanks for the useful info and the suggestions. Now I have the design up and running and operating within the correct voltage range.
Regards,
J.A.