[En-Nut-Discussion] Question about ADC stability

[Uwe Bonnes]

>>>>> "Rich" == Rich Wellner <ethernut at objenv.com> writes:

...
    Rich> It goes without saying, I hope, that I haven't been changing the
    Rich> temp dramatically.  I've also confirmed that the sensor it putting
    Rich> out a steady .232V, which is what I expect in my slightly warm
    Rich> workroom at the moment.  Are there additional things that need to
    Rich> be done to get steady readings from this adc?  Also, if I switch
    Rich> to SINGLE_CONVERSION then I get a more correct reading on average
    Rich> (e.g. about 23C), but it's still highly variable as with the
    Rich> readings below.

The AVR internal ADC is know to be dependant on many things. You get the
better (repeatable) results, the less work is going on during
conversion. Look at the description in the data sheet.

Another thing to care about is settling time of the ADC input driver
(circuits) and noise coupling into the input. Do any digital lines cross
your input?

-- 
Uwe Bonnes                bon at elektron.ikp.physik.tu-darmstadt.de

Institut fuer Kernphysik  Schlossgartenstrasse 9  64289 Darmstadt
--------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------