[sdiy] I2C DAC

[Jason Proctor]

i swiped my SPI DAC implementation from Stephen Hobley's site --

http://www.stephenhobley.com/build/lh_arduino.html

very simple and works fine for MIDI->CV etc.


>I don't mean to jump in on this thread, but can anyone show me an
>example of a 12-bit DAC  (I2C is fine) that is being used to output
>CV?
>
>I guess I was always under the impression that DAC chips were only
>useful for audio applications (that is, constantly changing values)
>and I never thought they could actually just "hold" a value and do it
>with any stability, etc.
>
>Mike
>
>
>
>
>On Sun, Jun 20, 2010 at 9:28 AM, Eric Brombaugh <ebrombaugh1 at cox.net> wrote:
>>  On 06/19/2010 02:09 PM, MTG wrote:
>>>
>>>  I'm almost out of pins, but I have two left in a project that I want to
>>>  hook a DAC up to for control voltages. Anyone recommend a decent I2C
>>>  single or multi-channel 0 to 5v voltage out DAC? What are most people
>>>  using for resolution of control voltages these days? I know 7-bits was
>>>  the standard for a long time. Is it worthwhile looking at higher
>>>  resolution for things like filter cutoff or pitch bend or ... ?
>>
>>  I think you'll have a hard time finding something as low as 7-bits
>>  resolution. 8 is pretty common, but for CVs is a bit coarse. 12-bit
>>  resolution will cover most CV applications without too much in the way of
>>  zipper effects and can even be used for reasonably accurate 1V/Oct scaling.
>>
>>  What processor are you using? Does it have a hardware I2C capability, or
>>  will you have to bit-bang the low-level protocol? I2C can be a bit tricky
>>  due to the built-in acknowledge cycle, and somewhat slow to update due to
>>  the relatively low clock rates. On some MCUs the pins available for I2C
>>  ports are limited due to the open-collector drivers required so you may not
>>  be able to arbitrarily reassign them.
>>
>>  Eric
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