sine wave generator help

HI
I am about building my first pic16f628 based inverter as a school project,
I was told that using square wave generator for inverters will reduce the efficiency of that inverter. I also notice that square wave inverter does not work well with inductive loads like fans and it generates a huming sound
Please how can i write an oshonsoft program to generate a sine wave (or close) with pic16f628 or other pics?
Thanks for your help

Do you want good resolution? If not, use PORTB as an ADC output with 256 levels. Use a timer to shove a lookup table out of the port (you only need 127 values as each quarter cycle will be the same table!

Cheers Ian

If I get you right, I will then need a DAC to give me the output. I need two outputs to drive 3 mosfets each, can you give me a dac ic part number?

I would use an R2R ladder on PORTB for the sine wave (If your'e making an inverter, the sine wave can be smaller,less resolution, 4 bits ) this will give you 8 levels positive and 8 negative on two outputs. or you can just use an MCP4922 dual output dac. Why three mosfets on each output? The last inverter I made, I drove the coil with only 1.

Thanks alot, i am going for Mcp4922. Get back to you if there is any problem. thanks