Subject:
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Re: digital and analog port on HD
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Mon, 18 Jan 1999 17:10:22 GMT
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Original-From:
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Will Bain <willbain@cs.umt.SAYNOTOSPAMedu>
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Viewed:
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995 times
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phillip chia wrote:
> I want to use the digital port as an analog port input. How should I
> convert the digital port to analog in using programming way ?
A digital port can't have the capability of an analog port, since it has
only one bit of information with which to work. (A 256-value analog
port has eight bits.) You could perhaps hook an analog sensor up to a
digital port using some sort of thresholding circuit (a voltage
divider/transistor combination), but you would have to preset the
threshold to a constant value, and the HB would then see it as a digital
device.
> if possible, how to convert the analog port to digital port also using
> programming .
Using an analog port as a digital, on the other hand, is easy.
> if (analog (12) <127)
> { ..............
> .............
> }
The above will not work (although I don't know what sort of error you
will get).
> else if (digital (3) == 1)
> { .................
> '..................
> }
The above would work ok, although it's a little more terse to say:
else if( digital( 3 ) ) {...}
It's the same as "if( analog( 3 ) > 127 )". It basically just throws
away the other seven bits of information.
Note that with an 8-bit D-A convertor circuit, one ought to be able to
use one analog port for up to eight digital inputs at a time.
-- Will
, ,
__@_/ \_@__ |/
| /__, o @_/
)\ ) ( \ (\/\\,
~~~~~~~~~ ' ` ~~~~~~~~~~~ ` ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Wendy Parson, There's a fine line between fishing and
Will Bain, just standing on the shore like an idiot.
& Tatoosh --Steven Wright
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Message is in Reply To:
 | | digital and analog port on HD
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| Hi, I want to use the digital port as an analog port input. How should I convert the digital port to analog in using programming way ? I do not quite understand the explanation on the technical manual handout. if possible, how to convert the analog (...) (26 years ago, 17-Jan-99, to lugnet.robotics.handyboard)
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