Hi Hank,

Note that the avr project needs at least 8 I/O pins to drive the resistor ladder(DAC). So with a PIC12f series you are stuck using PWM, serial DAC or a dedicated DDS chip.

I tried a spi DAC, too slow. Couldn't get over 600hz. It wouldn't be too hard to do the avr dds with a pic. Use a look up table and a loop and write each value to an 8bit port. Not sure how the speed would compare with an AVR?

This is the best, but it is expensive
http://www.sparkfun.com/products/9169

I wrote some code for this in PBP if you are interested.

cheers