Hi, this is my first post.
I'm working on this tube amplifier project:
http://www.solorb.com/elect/musiccirc/hammonator2/index.html
and want to use the Arduino to control a DAC chip for a vibrato circuit, it should replace
the waveform generator in that circuit. I need to generate sine waves from .1 hz to 20 hz.
The PWM DAC works ok for sine wave generation, but a 2 pole LPF causes the
waveform to change amplitude as the frequency varies.
Thus: I want to drive an 8 bit (parllel input) DAC from the port D pins.
I found the LCD Hola example, but that requires 8 calls to digitalWrite(), 1 pin at a time. (too slow).
I could use a '595 shift register, but that's a lot of extra wiring when port D is already there.
Is there a trick for writing a single byte to the port in one operation without the loop?
Seems like that should be trivial in assembly language.
SOLVED
Ok, I think I solved this myself, digging through the documentation a bit more I found:
looks like I can just do this:
DDRD = B11111111;
PORTD = B10101000;
Seems like some of the example apps should be changed to use this.