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From: chenness@cln.etc.bc.ca (CRAIG HENNESSEY)
Subject: Help on getting an A to D chip working..
X-Nntp-Posting-Host: cln.etc.bc.ca
Message-ID: <1995Aug12.000718.1763@news.etc.bc.ca>
Originator: chenness@cln
Sender: news@news.etc.bc.ca (System Administration)
Reply-To: chenness@cln.etc.bc.ca (CRAIG HENNESSEY)
Organization: The Education Technology Centre of British Columbia. (Canada)
Date: Sat, 12 Aug 1995 00:07:18 GMT
Lines: 55


        Hello there, i've got the A to D chip ADC0816CCN S9512AB, and
i'm having a heck of a time getting it to work.. uh, perhaps if i give
you the pins it'll help..

                 ---------------------
in 3             | pin 1      pin 40 | in 2
..               | ..         pin 39 | in 1
in 14            | pin 12     pin 38 | in 0
eoc              | pin 13     pin 37 | expansion control
in 15            |  "  14     pin 36 | add A
multiplexer out  |  "  15     ..     |
start            |  "  16     pin 33 | add D
vcc              |  "  17     pin 32 | ALE
comparator in    |  "  18     pin 31 | Data 1
ref (+)          |  "  19     ..     |
gnd              |  "  20     pin 24 | Data 8
                 |            pin 23 | ref (-)
                 |            pin 22 | clock
                 |            pin 21 | Output enabled
                 ---------------------

Whew, well that's sorta what it looks like.. the (in ?) pins are 1-16
different analog inputs, the (add ?) pins are to choose which of the
in ? pin to read, the (data ?) are the digital output.. ok so i have
most of the pins figured out.. the eoc is no big deal the start just
pulses to signal the start of conversion.. vcc i know gnd i know clock
i know.. so that leaves the
Multiplexer out
Comparator in
Ref (+)
Expansion control
ALE
Ref (-)
Output Enabled
pins.. i'm just using dip switches to choose which anolog input i pick,
but it never works.. so i fiddle with that for a while don't work..
then i get ref (+) to the +5 V input then i put ref (-) to ground and
i still get nothing.. so then i plug OE to my 5 V and ALE to the 5 V
and still get nothing.. so then i plug a 2.5 V wire into the Comparator
in, and i get exactly what i'm supposed to get as digital output..
a nice suprise after days of fiddleing, but still not good enough
cuz i can only get one input.... and it's not even one of the IN ? pins..
so that's about as far as i've gotten (oh and i've plug the clock into a
500 kHZ occilator crystal and i wasn't sure it was working except for
i got exactly the right digital output from the comparator in that i was
supposed to) any help at all would be greatly appreciated ( if you know
could you please describe what those 7 pins are/do that i have not a clue
about) thanks a million.. (oh yeah just remebered, when i use my
volt-meter on pins not being used i still get 0.7 - 0.8 volts.. like
for the ADD ? pins i'm not sure what it wants, 5V in through the switch
or letting the 0.7 V go to ground? ah well thanks for replying if you do)

        Craig.

