[PD] PD to CV redux (Arduino)

[Martin Peach]

derek holzer wrote:
> Hi Martin, Chris,
>
> and thanks for the enthusiastic replies!
>
> martin.peach at sympatico.ca wrote:
>>>> If I wanted to program an Arduino to send out Control Voltage for a
>>>> modular synth, what would the resolution be? Would it be better than
>>>> MIDI? Enough for microtones? Could it make quick modulations?
>>
>> The DAC716 is really good for this. It has 16-bit resolution so 
>> microtones can be quite finely tuned (10V/65536levels = 153microVolt 
>> per level). So you also need a clean power supply and careful circuit 
>> layout to avoid contaminating the control voltage with clock signals 
>> and switching noise from the rest of the circuit.
>> It would use three or four pins of the arduino: clock, serial data, 
>> load dac, and maybe chip select if you have more than one.
>
> So with one Arduino, how many chips could I control? In other words, 
> how many different CV channels could I get out of it?
>
> d.
If the Arduino has 12 usable digital outs, then you could use the same 
clock and data lines for all the dacs, as well as the same load dac 
line. Then you use the other 9 lines to select the individual dacs, so 
using no external address decoders you could have 9 dacs. Using a tree 
of decoders such as the 74HC138 on the 9 address lines could give you 
512 dacs.

Martin