Arduino LTC1660 Octal DAC demo

I was looking for a breadboard friendly DAC with lots of outputs, and decent resolution.

I found the LTC1660. It can be had for under $10, features 8 outputs, and 10 bit resolution. This should be good enough to control VCOs over a handful of octaves.

There seems to be a single example of how to use it with an arduino, but it doesn't spell out the SPI connections. Without SPI, you're limited to slow, CPU intensive communication. With SPI, I was able to get an example program to output at around 180kHz. This will be much slower in practice, but it shows the potential of the chip.

Below are the connections and code:

#include <SPI.h>
#include <stdint.h>
const int pinCSLD = 3;
const int pinCLR = 9;
 
void setup() {  
  pinMode(pinCSLD, OUTPUT);
  pinMode(pinCLR, OUTPUT);
   
  digitalWrite(pinCLR, HIGH);
  digitalWrite(pinCSLD, HIGH);
  SPI.begin();
  SPI.setClockDivider(SPI_CLOCK_DIV2);
}

void loop(){
  for (int i = 0; i < 1024; i++) setDAC(1, i);
}

void setDAC(uint16_t address, uint16_t value) {
    uint16_t h = address << 4 | value >> 6;
    uint16_t l = value << 2;
    PORTD &= ~(1 << pinCSLD); //LOW
    SPI.transfer(h);
    SPI.transfer(l);
    PORTD |= (1 << pinCSLD); //HIGH 
}

Werkstatt Breakout

Here's a quick and dirty solution to the Werkstatt's desperate need of proper connectors. Moog has their offering, but I think this is perfect DIY fodder.

First I chose the connections I wanted to breakout and which should get adjustment knobs.
I pulled some potentiometer values from a hat and started making a schematic.
There isn't a nice header for ground, so I added a 1/4" connection just for the ground connection.
I also added a zener to protect the gate input. Note: the Werkstatt needs to be modified to safely accept a gate/trigger input. I simply severed the envelope generator's connection to the sustain switch.

Here's my schematic:

I like the roominess of 1590BB enclosures, so I used one for this project. I mocked up the parts in Inkscape and threw together this layout:

I printed it out as a template and drilled the case. Some paint, solder and dymo-tape later it looks like this:

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