[Color Computer] [coco] Learning MW C

[jdaggett at gate.net]

On 14 Aug 2006 at 0:32, James Diffendaffer wrote:

> --- In ColorComputer at yahoogroups.com, "George's Coco Address"
> <yahoo at ...> wrote:
> >Should I wish to step these motors faster, I need to also use
> > a modified sine wave. I figure four bits per coil could do this. Of
> course,
> > this takes more time for the computer to do and speed is getting more
> > serious.
> Can you precalculate a table for the sine wave and then just figure
> the starting point in the table to start sending values from?

*************************

Analog Devices makes low frequency DDS (Direct Digital Synthesis) chips 
that uses 32 bit serial or parallel command to set the frequency.  The 
AD9831 will synthesize any frequency from ab out 1 Hz to 12.5 MHz in 1 Hz 
steps. A well designed post filter and an external 25MHz clock frequency and 
then the computer can just upload the frequency encoded in four bytes to the 
chip. 

james