So I have this school project to create a DAC converter, and we will have to make it write out a sine-wave on a oscilloscope. I decided to make a R-2R converter, but for some reason it is not working. I have tried to connect it to a oscilloscope to get out a graph, but it is just noise. Can anyone p…

And was not too hard to find this... Sine Waves generating uisng OPAMPS.

Johnny010: I am unsure as to how you think that circuit would make a sine wave in the first place? Are we missing something? The circuit alone won't produce any sine-wave, but you be able to convert digital signal to analog. And with some code you will have a sine-wave.

Yeah, a modified wave is fine. The only requirement to frequency is that you should be able to change between two frequencies with a button, and change between to wave-form with another button.

I could not find the code tags. So ill post it without. It is a simple code, it should output triangles, but the result is just some random noise. Btw I am new to electronics, so all the documents on online does not tell me anything. I honestly dont understand anything of them. void setup() { // …

Can you not use the PWM ( analogWrite ) ?

You were close. You need to use the sin(). Read up about your maths...sine/cosine/tangent.

What board are you running that on? This implies a Mega: for (int i = 38; i < 46; i++) { pinMode(i, OUTPUT); } Yet D38 to D46 is not PORTD on a Mega. arduino-mega2560_R3-sch.pdf 47.06 KB Try PORTC and 30-37, PC0 = 37, PC7 = 30.

So a sin equation such as: analogWrite((128*sin("some maths here to get the correct frequency"*x)+128)) x++; Will give a sine curve from 0 to 256 centred about 128 on the y axis. 128*sin((1/10)x)+128 Pop that in the calculator below and play with the value before the x to see the effect on it an…

8-bit R-2R DAC need help.

Projects General Guidance

Johnny010 October 16, 2015, 5:16pm 11

Oh, you are doing this with an MCU?

So take a digital value and make a sine like output?
Assuming frequency of the output is proportional to the digital value?
What are the ranges?

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8-bit R-2R DAC need help.

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