[comp.dsp] simple dsp programming questions

pts@faraday.clas.Virginia.EDU (Paul T. Shannon) (03/23/91)

I'm looking for some help with two simple 56k dsp programming tasks:

   1.  sit in a loop til an external voltage level goes high 
   2.  delay a host-specified number of milliseconds, and then
       produce a short tone.

For the first task, I imagine that I should use one of the SCI pins.

Since I'm doing this on a NeXT, the second task should probably 
play the short tone to the NeXT sound hardware.

I've pored over the sample programs NeXT provides, but either they
don't do what I need, or I missed it.  I think that I *do* understand
how to use the SND functions to load and run a program on the dsp.
I've made some progress from reading the DSP User's Manual, but I've
only moved from a state of total blindness to one of partial vision
in one eye on a moonless night...

I'll be grateful for any help, especially short dsp programs.  Thanks.

 - Paul Shannon
   pts@Virginia.EDU