Michael Schippling ha scritto: > Okokok, I'll stop impugning your BOB soldering... > sounds like it's "something else". > > There is apparently no public schematic for the IRIS > so we can't check what "they" though they were doing > hardware wise. The ADC channels should be independent > and just enabling one for reading shouldn't affect > the others, however if they are open maybe there's > some bleed through. Once you get your connector, try > just grounding the new ADC input and see what you read.
If I connect ADC1 channel to the GND I read:
ADC1 0, Voltage 307
ADC1 0, Voltage 307
ADC1 0, Voltage 307
ADC1 0, Voltage 307
ADC1 0, Voltage 307
ADC1 0, Voltage 307
ADC1 0, Voltage 307
ADC1 0, Voltage 307
Those readings are the same that I get by connecting the potentiometer
to the break-out board and turning to one side ("2" in the following
example):
ADC1 1023, Voltage 733 <--- axle on side "1"
ADC1 1023, Voltage 733
ADC1 1023, Voltage 733
ADC1 921, Voltage 705 <--- rotation
ADC1 767, Voltage 602
ADC1 607, Voltage 496
ADC1 222, Voltage 330
ADC1 0, Voltage 307 <--- axle on side "2"
ADC1 0, Voltage 307
ADC1 0, Voltage 307
> What version of TOS are you using? It's possible, but
> somewhat hard to believe, that the ADC code isn't switching
> channels correctly. Or that the Voltage sensing is not
> correct.
Now I have TinyOS 2.1.0. After I can try with TinyOS 2.1.1 and see what
happens.
> On the mica's one needs to turn on an external
> voltage ref in order to get a good reading (on mica2
> at least, I forget about the micaz). If the VoltageC
> code isn't doing that, then maybe everything you read
> is noise.
>
> I only know mica2 under TOS1.x. I use 6 of the ADC channels,
> including battery and RSSI, sampled at TOS_ADCSample240us
> (the second slowest pre-scale setting). I have not noticed
> (nor looked seriously) any cross-channel interference.
> The mica's use a slightly different ATMEGA chip, but
> it "should" work about the same.
Yes... ATMega 1281 for IRIS, but, as you say, it should work about the same.
> I guess you're on your own here. If you can characterize
> the problem maybe you can get the suppliers, whomever they
> are now, interested in fixing it...
>
> sorry...
> MS
I also found another topic with my problem:
http://tinyurl.com/4e7dd9k
Ok Michael... if I find anything interesting I will inform you and thank
you very much for your help and your patience.
Greetings,
--
Francesco Ficarola <francesco.ficarola_at_gmail_dot_com>
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