Light mayhem, could anyone help.

Hi, Basically i have built an electronic project, it is a set of trafic lights using a Darlington Driver and a D25 connector, i built that no problems and it works, i know this because in college my programming lecturer helped my right a program in C to control these lights and sequence them.

Ok they worked fine at college and i was quite happy.

BUT......

When i got home i thought i would try and re create the scene, by writing the program in Turbo C. so i wrote the program, of which the code i shall show in a moment, but i noticed when i pluged the D25 into the back of the computer, all the lights stayed on, they did not do this at college, i tried it on another of my computers, and the same. how can i get them to turn off?

My code:

#include <stdio.h>
#include <dos.h>
#include <conio.h>

void main(void){
int Led[4]={33,19,12,26};
int i=0;
int Time;

while(!kbhit()){
outportb(0x378,Led[i]);

switch (Led[i]){

case 33: Time = 2000;
break;
case 19: Time = 500;
break;
case 12: Time = 1500;
break;
case 26: Time = 500;
break;
}

Delay(Time);
i++;
if (i>2);
i=0;;
}
}
outportb(0x378,0);

With this code i get a number of Declaration Sytax errors, and "i is assigned a value that is never used in function main"

This is not my code, it was mostly written by my programming lecturer, so i do not understand it all, i understand most of it and the idea of it, as i am still learning C.

If anyone could help me out id appreciate it, i cant imagine that there is anything wrong with the code because it was working in college, unless i have written it down wrong. But i think that the main problem is all the leds staying on, im sure the errors are easily fixable.

Any help would be appreciated.

Thanx

Jon

Your code has multiple problems.

Code:

void main(void){

main never returns void. It always returns an int. Always.

Code:

i++; if (i>2); i=0;;

Multiple problems:

This if check actually does nothing, because you have a ; at the end of it.
This will always set i to zero because of the if check.
Assuming this did actually work, you still will never get 'Led[3]', because once it reaches 3, it is immediately set back to zero, without ever running 3 through the switch.

On a side note, you have a pointless double ;; at the end of your assignment, when you only need one.

Quzah.

i must apologise, some of those errors, were typos on my part!! it was late!!

in my code there is no double ;; at the end, and on the if statement instead of a ; there is a {.

oh and i wrote down, if (i>2){ i=0;}

it was suposed to read:

if (i>3){
i=0;
}

is this correct,as thats what my code actually says,

but the lights all still turn on when they are plugged into the back of the computer, regardless of whether or not Turbo C is even open!!!

do you know how i can stop it from doing this, because i think,that maybe when/if the code does work, its not going to be able to do the light sequance becasue they are permenantly on.

Thanks

Jon

yes sorry for that, i use a different computer for that kind of work.

i am running .NET Server 2003 on the computer at home, and Windows 95 at college.

Thanx

jon

When you post a code here, use code-tags this will make your code more readable, don't forget.

Hmm, im lost, i thought i would run a little test, so i set up another machine, this time an exact replica, an old p1, running Win 95, the same as college.

But the same problem occurred, but this time, on side of the lights stayed on and the other side went crazy flashing on and off!!

Any ideas,

tried all the settings mate, makes no difference, all the lights still stay on.

I cant understand this,

all the lights stay on whether or not any program is open, they just stay on as long as they are plugged into the parralell port and the battery is plugged into them.

does anybody know if i can force the lights to turn off and respond the the program, is there soem code i can use to force the lights to turn off

Code:

#include <stdio.h> #include <dos.h> #include <conio.h> void main(){ int Led[4]={33,19,12,26}; int i=0; int Seq while(!kbhit){ outportb(0x378, Led[i]; switch(Led[i]){ case 33: Seq = 3000; break; case 19: Seq = 500; break; case 12: Seq = 1500 break; case 26:Seq = 500; break; } delay(Seq); i++ if (i>3){ i=0 } } } outportb(0x378,0);

This is an EXACT copy of my code, i am still coming up with numerous errors..

-Declaration Syntax error in function main.
-declaration missing ; in function main.
-i is assigned a value that is never used in function main.
-Led is assigned a value that is never used in function main.
-Declaration syntax error
-declaration syntax error

I wrote the code, but i had some help with parts of it from my tutor, he dident put any errors in it, cuz i wrote it and i had it workign at college, but i can figure out where ive gone wrong at home.

ive fixed the missing semicolons, but still errors

cant figure it out.

Code:

#include <stdio.h> #include <dos.h> #include <conio.h> void main(){ int Led[4]={33,19,12,26}; int i=0; int Seq; while(!kbhit){ outportb(0x378, Led[i]); switch(Led[i]){ case 33: Seq = 3000; break; case 19: Seq = 500; break; case 12: Seq = 1500; break; case 26:Seq = 500; break; } delay(Seq); i++; if (i>3){ i=0; } } outportb(0x378,0); }

Wahoo, i think i got rid of all the errors, it compiles but doesent run, just stays on the blue coding screen.

Strange