creating code for a square wave output and sine wave output

[basementjacks]

hi im just wondering about finding code to create a square wave output  and a sine wave input&output for the Arduino UNO rev3. i need to measure the voltages and currents going in and out of the board with an oscilloscope and signal generator. any help would be greatly appreciated

[KeithRB]

Since the UNO has no DAC output, a sinewave is kind of tricky. You can filter the PWM output, but it might not be very clean.

[AWOL]

I hope your lecturer isn't a member here - many are   
You can build a four or five bit DAC easily with an R-2R resistor ladder (useful Google search term)

[DuaneB]

For generating output waveforms you should try Direct Digital Synthesis, this project uses it for the waveforms you mention and also has some useful links -

http://rcarduino.blogspot.com/2012/08/the-must-build-arduino-project-illutron.html

Duane B

rcarduino.blogspot.com

[basementjacks]

You can build a four or five bit DAC easily with an R-2R resistor ladder (useful Google search term) 

is there a way to do it using the circuit i already have for my project? the schematic is below
  http://www.instructables.com/file/F6DPG7PGZMIUHMJ