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.model tiny
msgLED db "Turn off all LED at parallel port...$", 0ah, 0dh
mov ax, @data
mov ds, ax
mov dx, offset msgLED
mov ah, 09h
int 21h
mov al, 0h
mov dx, 378h
out dx, al
mov ax, 4c00h
int 21h
end start

according to my reasearch this code will turn off all the LED .
but it doesn't . .
it only display the message "Turn of all LED at parallel port " but
it does not affect the LED .
can someone tell me how this code work??
thank you
Updated 17-Mar-13 5:35am
Andreas Gieriet 17-Mar-13 6:26am    
How do you think we can help?
1) never post the same question twice, this is annoying "noise" for the rest of us.
Improve the initial quesiton to make it attractive to help you.
2) If you do not provide a *concrete* question *including* concrete data, noone can really help.
Provide the code that fails, with concrete description what means "failed".
3) "Help me please..." is childish, sorry. No begging on CP please.
4) Ask yourself what help you expect! Do you expect anyone to spoon-feed you?
If it is a homework assignment consult your text book and talk to your class mates/teacher.

We are more that willing to help on concrete questions that allow "quick answers". This is the "quick answer" forum.
PS: See my solution#1 to the original question.

1 solution

You asked the same question yesterday: HOW TO MAKE LED Light USing PARALLEL PORT[^] pretty much.

Then you were asked: What have you done so far? What have you tried? Where are you stuck?

We do not do your homework: it is set for a reason. It is there so that you think about what you have been told, and try to understand it. It is also there so that your tutor can identify areas where you are weak, and focus more attention on remedial action.

Try it yourself, you may find it is not as difficult as you think!
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arjel29 17-Mar-13 5:05am    
I try it by my self .
and i did not focus on what ive been post yesterday
itry my self to make my own code .
searching for internet for references. .
but nothing happened ..

my program had no errors but it did'nt light a single led at all
Nelek 17-Mar-13 5:53am    
So... if you tried it and it didn't work, use the "improve question" widget to add a piece of code giving you problems. It will make it much easier for the people here to help you.

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