Author Topic: adc0809 connected to parallel port  (Read 10088 times)


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adc0809 connected to parallel port
« on: November 14, 2012, 01:21:01 am »
Dear Sir

I am trying to build the ADC0809 circuit in you book Parallel port complete. I only read a value of Fff for each channel. Do yo have any suggestions of what the problem may be ?

The input is 0-5V to pin 1.
My PC system is a Pentium Dual core, using VB2005

I have used your original program and imported it into VB2005.

Could the speed of the PC system play any influence ?

If I change the program just to read one channelnumber, for instance channel 1, only channel 1 give a value of Fff. The other 7 channels show 0.

Thanks for you feedback.

Jan Axelson

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Re: adc0809 connected to parallel port
« Reply #1 on: November 14, 2012, 11:43:04 am »
To isolate the problem, use a voltmeter or 'scope to monitor the voltages on the pins. Use single-stepping to step through the program.