mOBiTh

Retrocade ADCs - 12bit upgrade?

8 posts in this topic

Hey guys

Just wondering whether these 12bit ADCs from TI are a straight swap out with the Retrocade 8bit ones:

http://www.ti.com/lit/ds/symlink/adc128s102.pdf

The 8bit ones are:

http://www.ti.com/lit/ds/symlink/adc088s102.pdf

It's not a big deal at the moment for prototyping and the grove analogue block was written for 12 bit ADCs by the look of it (not sure why?), so I probably won't desolder the ones I have.

However I thought when I get my own custom megawing built I could just swap these 12 bit ADCs straight in. 

Also, sometimes I get spurious 'crosstalk' between my ADC inputs but I'm not using all of them and the unused ones are currently floating unfortunately. Do you think the interference is likely the floating inputs or a dry solder joint (the situation tends to improve when I press on ADC0). I'm only using c0, c2, c4 and c6 of ADC0.

Any thoughts?

Cheers!

Matt

 

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What kind of crosstalk are you talking about? I don't remember seeing any crosstalk in my testing but the analog inputs are always jumping around. 

Jack

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Basically the effect is that when I touch a pot connected on ADC2, say, ADC4 changes value. (ADC1 and 3 are unconnected).

However I haven't grounded the unused ADC inputs (they're floating which apparently isn't recommended?) so that could well be the issue, but the issue seems to go away if I press the ADC IC. So maybe I should just resolder that part.

Anyway, no big deal for now because I need to make a much bigger 16 pot input board this weekend to connect to the ADCs. Will see what happens when they're all in use. 

Thanks for your help!

M

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I just featured and pinned that other post because it has such useful information in it.

 

Jack.

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