[mythtv-users] Recording LED almost working.

[Rick St.Pierre]

I have 2 LEDs working, one for each of my PVR-250s.   I built a
parallel port cable based on a design I found on the web (I can't
remember where, but it was a very simple circuit).

I then have cron run this simple script every minute.  I have always
wanted to see if there was a way mythtv could run this script
automatically when it starts/stops recording, but haven't had the time
to look into it.  The script is:

#! /bin/sh

if [ `fuser /dev/video0 | grep -cv grep` == "0" ]
then
        if [ `fuser /dev/video1 | grep -cv grep` == "0" ]
        then
        /usr/local/bin/lpt_light 0
        else
        /usr/local/bin/lpt_light 2
        fi
else
        if [ `fuser /dev/video1 | grep -cv grep` == "0" ]
        then
        /usr/local/bin/lpt_light 1
        else
        /usr/local/bin/lpt_light 3
        fi
fi


the lpt_light program is a simple little program I wrote myself.  A
parameter of 1 turns on the first light, 2 the second, and 3 both
lights.  The code is:

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <asm/io.h>

#define base 0x378

main (int argc, char **argv)
{
    int value;

    if (argc != 2)
        fprintf(stderr, "ERROR - Wrong number of input arguments.\n"), exit(1);

    if (sscanf(argv[1],"%i",&value)!=1)
        fprintf(stderr, "ERROR - Parameter is not a number.\n"), exit(1);

    if ((value<0) || (value>255))
        fprintf(stderr, "ERROR - Invalid numeric value.\n"), exit(1);

    if (ioperm(base,1,1))
        fprintf(stderr, "ERROR - Could not access printer port.\n"), exit(1);

    outb((unsigned char)value, base);
    
}

Hopefully this helps some people out.  The only down side is the light
will only change when the script is run.  I am hoping to find time to
get working on the mythtv code soon, and maybe integrate this better.

Rick.


Thursday, June 10, 2004, 5:35:17 PM, you wrote:

DT> Garry wrote:

>> Something seems to be spewing stuff to the parallel port.
>>
DT> I noticed the same thing when I created my parallel port LED device.  It
DT> seems that on some motherboards the interrupt status is reflected on
DT> various parallel port lines.  The only solution that I found was to buy
DT> an add-in parallel port PCI card and disable the port on the motherboard.

DT> -Dave




-- 
Rick St.Pierre
rsp Acoustics
mailto:rick at rspacoustics.com