#include <stdio.h>
#include <fcntl.h>
#include <machine/cpufunc.h>


/* John L. Sokol
   http://www.unixprogram.com

   Program to set bit on printer port of PC.
   works with R2R ladder D/A converted from 
     http://www.dnull.com/zebraresearch/images/Schematic0.jpg
  See Audio Byte site at http://www.dnull.com/zebraresearch/ 

  this code generates a triangle wave output..
  
   Tested in Via EPIA M10000 with FreeBSD 4.9 and 4.11

*/

main(){
 int file;
 long a,b;
   file = open( "/dev/io",O_RDWR);

 for(;;){
 for(b=0; b < 255; b += 1){
  for(a=0; a < 20000; a++) {} 
   outb(0x378,b);
 }
 for(; b > 0; b -= 1){
  for(a=0; a < 20000; a++) {} 
   outb(0x378,b);
 }
}
}