file: slh_demo.c


#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <math.h>
#include <errno.h>
#include "slh.h"

#define PUMP_FILE "./SLHDMX16.BIN"

unsigned char buffer[NUM_DMX_CHANS];

void print_dmx_channels();

int
main( )
{
	int          fd;
	int          retval;
	struct stat  stat;
	void        *pump_buf;
	DMX_CHANNELS dmx_channels;

	/* open the pump file */
	fd = open( PUMP_FILE, O_RDONLY );
	if ( fd < 0 ) {
		fprintf( stderr, "cannot open pump file (%d)\n", errno );
		exit ( -10 );
	}

	/* get the pump file stats to determine the file size */
	retval = fstat( fd, &stat );
	if ( retval < 0 ) {
		fprintf( stderr, "cannot get pump file stats (%d)\n", errno );
		exit ( -20 );
	}

	fprintf( stderr, "Pumping Board; size = %d\n", (int)stat.st_size );

	/* allocate buffer to hold pump file */
	pump_buf = malloc( (size_t)stat.st_size + sizeof(long) );
	if ( pump_buf == NULL ) {
		fprintf( stderr, "unable to malloc() pump buffer\n" );
		exit ( -30 );
	}

	/* read in pump file to buffer */
	retval = read( fd, pump_buf+sizeof(long), (size_t)stat.st_size );
	if ( retval < 0 ) {
		fprintf( stderr, "cannot read pump file (%d)\n", errno );
		exit ( -40 );
	}

	/* copy the pump file length into the first word of the buffer */
	*((unsigned long *)pump_buf) = stat.st_size;

	/* open soundlight 1512b device */
	fd = open( "/dev/slh", O_RDWR );
	if ( fd < 0 ) {
		fprintf( stderr, "open( /dev/slh ) failed (%d)\n", errno );
		exit ( -50 );
	}

	/* pump the board */
	retval = ioctl( fd, SLH_IOCPUMP, (char*)pump_buf );
	if ( retval < 0 ) {
		fprintf( stderr, "ioctl( pump ) failed (%d)\n", errno );
		exit ( -60 );
	}

	/* free pump file buffer */
	free( pump_buf );

	/* print non-zero DMX-512 channels */
	print_dmx_channels( fd );

	/* set board parameters here ??? */

	/* zero channel structure */
	memset( (void *)&dmx_channels, 0, sizeof(dmx_channels) );

	/* set channel values */
	dmx_channels.num_chan = 2;

	/* change dimmer 6 value to 125 immediately */
	dmx_channels.chan_value[0].channel    = 6;
	dmx_channels.chan_value[0].new_value  = 125;
	dmx_channels.chan_value[0].transition = 0;

	/* change dimmer 509 value to 82 taking 5 seconds  */
	dmx_channels.chan_value[1].channel    = 509;
	dmx_channels.chan_value[1].new_value  = 82;
	dmx_channels.chan_value[1].transition = 5;

	retval = ioctl( fd, SLH_IOCSET, (char*)&dmx_channels );
	if ( retval < 0 ) {
		fprintf( stderr, "ioctl( set ) failed (%d)\n", errno );
	}

	print_dmx_channels( fd );

	exit ( 0 );
}


void
print_dmx_channels( int fd )
{
	register int i;
	int          retval;
	int          found;

	fprintf( stderr, "printing non-zero channels:\n" );

	/* This sleep is not necessary.  But, if channel values are set
	 * [using ioctl()] and print_dmx_channels() is called immediately
	 * afterwards, the change might not be seen since it is not actually
	 * made until the next channel timer expiration which ocurs every
	 * 50ms.
	 */
	usleep( 50000 );

	/* read in DMX-512 channel values */
	retval = read( fd, buffer, NUM_DMX_CHANS );
	if ( retval < 0 ) {
		fprintf( stderr, "read( chans ) failed (%d)\n", errno );
		return;
	}

	if ( retval != NUM_DMX_CHANS ) {
		fprintf( stderr, "read( chans ): num_chans=%d\n", retval );
	}

	/* print non-zero channels */
	for ( found = 0, i = 0; i < 512; i++ ) {
		if ( buffer[i] == 0 ) {
			continue;
		}
		fprintf( stderr, "\tchan(%d)=%d\n", i+1, (int)buffer[i] );
		found++;
	}

	if ( !found ) {
		fprintf( stderr, "\tNo non-zero channels\n" );
	}
}



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