Guys please help me with this question coz all the interviewers ask this to amature programmers. I have done my Embedded Systems course recently but wasnt able sort to this question. Thanks and reply soon.
The reason this question is asked is because the answer is VERY simple. If an interviewer asks this question to an interviewee who doesn't know the answer, the interviewer knows the interviewee is probably pretending to know something he doesn't. My suggestion is to do a little research and try to figure it out on your own. Jon
Dear Jon; i did a little research then only i have posted this que. so i would be really gratefull to you if you gimme the solution for it orelse aleast a hint abt it. regards; amin
Look at sample board schematics like: http://www.keil.com/manuals/mcbx51.pdf
"I have done my Embedded Systems course recently but wasnt able sort to this question." What sort of Embedded Systems course lets you get all the way through it without knowing how to drive a LED?! "i did a little research" Really?? The internet is absolutely awash with examples of LEDs connected to all sorts of processors (including 8051s) - including the example cited by Keil Support, Intl. Here's over 20,000 to get you started: http://uk.altavista.com/web/results?itag=wrx&q=%2BLED+%2B8051&kgs=0&kls=1 How did you manage to miss it all?! Try this: http://www.8052.com/forum/read.phtml?id=77588
I m really sorry Andrew but i was never taught that thing and i was asked in an interview that is why posted a quetion to u master guys in 8051....thx for links and i will get thru it by my own....really thank you very much...amin
"i was never taught that thing [driving a LED] and i was asked in an interview" As Jon suggested, that interviewer will also be thinking, "What sort of Embedded Systems course lets you get all the way through it without knowing how to drive a LED?!"
Here's a problem with your request. The answer is different based on the driving port voltage. Furthermore, it may be different for different LEDs. And, it will certainly be different depending on the current driving capacity of the port pin and the current requirements of the LED. Anyway, here a hint. V = I * R Jon
For those seeking the shirt, the URL is: http://www.computergear.com/virtshirt.html Jon
I like this one: http://www.computergear.com/rtfmtshirt.html