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.
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
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