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I'm trying to implement a volume dial. I've got a potentiometer hooked into ADC 0832B (http://www.ti.com/lit/ds/symlink/adc0832-n.pdf), timing diagram below:

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When I turn the volume dial, I want an interrupt to happen, then I'll start reading the data. Is there any way this chip can issue an interrupt?

I also read that SPI on rpi does not work in slave mode, so does that mean the adc cannot initiate the data transmission?

The only other way I can think of handling this is by creating a new thread which continuously polls the adc. This doesn't seem like an efficient solution though.

Do ADC chips normally have some kind of interrupt feature? Or is threads the normal way of handling this?

Thanks!

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The datasheet will specify if the chip generates an interrupt or not. I don't see why it would.

The normal procedure is assert SPI slave select and send command (which triggers a reading) then read result and de-assert SPI.

I guess you could poll ten times a second or so. The load on the Pi would not be measurable.

Why not just use a rotary encoder like most other users?

  • Rotary Encoder! Just looked that up and that seems wayyyyy better. That'll be easy to use with interrupts too. Thanks! – Nick Lang Oct 25 '16 at 20:25
  • @NickLang I know this is an old question now, but I've written a kernel driver for using a rotary encoder as a volume control, source and instructions can be found here if you're interested: github.com/JamesGKent/rotary_volume – James Kent Apr 6 '18 at 15:17
  • @JamesKent amazing! i'll check it out – Nick Lang Apr 6 '18 at 17:46

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