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mosquito56
01-17-2008, 02:03 PM
·The datasheet for the adc0831 says
·· "Input and analog voltage: -.3v to +.3v"
·· "clk freq of 250khz"

I run 3v from the prop to the chip for CS, CLK and no timing worries on the clk. It just goes hi and low and spits out bits. Thanx to Larry F. for the beginners level object.

I don't get how this works? Is the datasheet wrong or what? It seems like the prop would be running to fast for the adc but it works fine. Is the prop slower than I thought?

Help is appreciated as I continue to explore more advanced adc's.

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Hmm, "What do you mean, it doesn't have any tubes?"

······· "No such thing as a dumb question" unless it's on the internet
········"What happens in Vegas ends up on the Internet"

Technologically challenged individual, Please have pity.

OzStamp
01-17-2008, 02:14 PM
Hi mossie

Read the datasheet .. it say's max clk rate is 600KHZ.
We have pushed it as far as 400KHZ 4 off them simultaneously.(see our post here recently as well)
Also the "in" Hi threshold is 2V and low threshold 0.8V ( both on the clk and cs lines)
So as long as you power it up on VDD and VSS 5V it will work..

The beauty with the adc0831 or tlc0831 is that you can read a value of 0-255 over a 1Volts Delta..(change)
If you set the minus ref pin to 2V and the plus ref pin to 3 V you will read 0-255 between those 2 values..
Which is approx 4mV resolution... not bad for a simple a/d chip..

cheers
Ron Nollet mel ozzie

Post Edited (OzStamp) : 1/17/2008 7:44:01 AM GMT

mosquito56
01-17-2008, 03:11 PM
That makes sense. I guess I missed the 600khz. Yes, nice chip but a bear for the first timer. I spent an hour trying to make a 250khz pulse rate. Turned out to be a loose wire on a pin. Would show fine on ohms. I accidently hit it and voila.

Going to be trying the max1270? next. Have a good one.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Hmm, "What do you mean, it doesn't have any tubes?"

······· "No such thing as a dumb question" unless it's on the internet
········"What happens in Vegas ends up on the Internet"

Technologically challenged individual, Please have pity.