Diagrams

The diagram for the analog setup:

 

The diagram for the code structure:

Code and DAC construction

After making the diagrams, I constructed the code and the DAC.

The DAC ended up looking like this:

The four red wires coming from the PIC is the four input bits.

The other wires are connections for 15 volts, -15 volts, output and ground.

The code for the counter is as follows:

#include 

void main()
{
 TRISD = 0;
 
 PORTD = 0b00000000;

while(1)
{

PORTD++;

if(PORTD == 16)
{
 PORTD = 0; 
}

for(int i = 0 ; i < 30000 ; i++);
 
}
}

Measuring results

 After getting the code to run and assembling the 4 bit DAC converter I went to the lab to measure it.

The code is written to make a slow curve. The upper curser is placed at approximately 0 volts and the lower curser is set at approximately – 4 volt.

Step up jump zero. Cycle time 1.5 second

Step up step down. Cycle time 3 seconds

Sinus wave. Cycle time 3.6 seconds

Here is a video of the sinus wave: