Hey there,

today i will show you how to control 8 LEDs over the LPT Port… And yes.. i will use the ugly LPT to breadboard cable

1. wiring the breadboard:

• connect the anodes with the 8 data pins (2 – 9) from the LPT Port.
• connect the cathodes with a suitable Resistor to one of the LPT ground pins (18-25)

PIN-2 — (+) >> Diode >> (-) — Resistor — GND
PIN-3 — (+) >> Diode >> (-) — Resistor — GND
PIN-4 — (+) >> Diode >> (-) — Resistor — GND
PIN-5 — (+) >> Diode >> (-) — Resistor — GND
PIN-6 — (+) >> Diode >> (-) — Resistor — GND
PIN-7 — (+) >> Diode >> (-) — Resistor — GND
PIN-8 — (+) >> Diode >> (-) — Resistor — GND
PIN-9 — (+) >> Diode >> (-) — Resistor — GND

I used LEDs with an integrated Resistor.

Programming the LPT port:

here is my tiny C program ive used for the video. It uses the ppdev kerneldriver. i will release the windows port in a few days

pptest.c

/********************************
pptest

small and simple demoprogram to test
the LPT port.

this code was hacked in 5 minutes
and HANDLES NO ERRORS! 

2012/12/31 by Tino Goehlert (cmdrk33n)

http://cmdrkeen.net

********************************/

#include <fcntl.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <linux/ppdev.h>
#include <unistd.h>
#include <stdlib.h>

int parportfd = 0;
unsigned char r_data = 0x00;

unsigned char togglepin(unsigned char pin)
{
	r_data ^= 1 << pin;
	ioctl( parportfd, PPWDATA,&r_data);
	return r_data;
}

unsigned char clearpin(unsigned char pin)
{
	r_data &= ~(1 << pin);
	ioctl( parportfd, PPWDATA,&r_data);
	return r_data;
}

int main()
{
	parportfd = open("/dev/parport0", O_RDWR);
	ioctl( parportfd, PPCLAIM, NULL );
	//
	int repeats=0;
	for(;repeats<=10;repeats++){
		int pin = 0;
		for(pin=0;pin<8;pin++){
			togglepin(pin);
			usleep(50000);
		}

		for(pin=0;pin<8;pin++){
			clearpin(pin);
			usleep(50000);
		}
	}

	ioctl(parportfd,PPRELEASE);
	return 0;
}

pptest running on arch linux X64: