I'd like to generate a sawtooth wave, 0 to +1.5v at several hundred Hz up to 1 kHz on a 16F690 or similar, to generate a time base for CRT.

Suggestions for an efficient way to do this on a PIC?

My alternatives are a 555 and RC circuit or parallel DAC. I've tried an I2C DAC, but it's too slow with I2CWRITE commands.

Thanks.