Arduino-True-DAC

This library implements a true 12-bit DAC on Arduino pins 2 - 13 with R-2R resistor ladder. 10-bit and 8-bit options also available.

The Digital-Analog Converter (DAC) is formed on pins 2 - 13 with the R-2R ladder which is connected as shown in the diagram. The output voltage changes from 0 to 5 V corresponding to the DAC input setting ranged from 0 to 4095 (integer).

How to use

1. Simply download this library folder into your Arduino user libraries folder which is by default located in your Arduino workspace (on Windows 7 it can be found at C:\Users\%Username%\Documents\Arduino\libraries\)
2. Add #include "ArduinoTrueDAC.h" directive to your sketch file
3. Initialize DAC under the void setup() with DAC12INIT function
4. Use DAC12OUT function for analog output

See examples for reference.

Note that the execution of DAC12OUT approximately takes 17 microseconds on Arduino UNO R3, Atmega328P.

One can use 1 kOhm resistor for R and 2 kOhm resistor for 2R. The author used 1 kOhm and 2 kOhm metal film resistors with 1% accuracy.

For better stability output signal filtering is recommended with an RC integrator comprised of 1 kOhm resistor and 100 nF ceramic capacitor which gives integrator specific time of 100 microseconds.

Example - Sinewave