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AT89C51 Simple LED Blink


Moderators: Ajay, Junied , abbas1707, Arun Kumar V, pdi33, Shailesh NAYAK, ۞ TPS ۞, shyam, sashijoseph

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say2paul

Sat Jun 28 2008, 11:09AM

Registered Member #8461

Joined: Tue Jun 17 2008, 10:56AM

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Today I got my first microcontroller programmer for 8051 from www.sunrom.com (1001-3456 v2)

I downloaded the example hex file provided by sunrom to the AT89C51. It was a very simple example to blink the LED connected to any pin of port 2.

I designed the following circuit in Proteus ISIS and it ran successfully without any error with the attached HEX code. But when I designed the same circuit on the Breadboard then the same is not blinking the LED, instead it just turn on the LED. I cross checked all the connections and found that connections are correct. I downloaded the HEX file on another AT89C51 and tried.. again the same thing.

What is wrong, please help me. Can anyone try this at their end and PLEASE let me know where I am wrong!

say2paul

Sat Jun 28 2008, 11:12AM

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Joined: Tue Jun 17 2008, 10:56AM

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Please find attached the zip file containing the C and HEX code.

ledtest.zip

۞ TPS ۞

Sat Jun 28 2008, 11:32AM

Registered Member #2712

Joined: Tue Jul 31 2007, 12:06AM

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you are not using pin no 9(RST) and 31 EA/VPP Connect it properly you will get the result best of luck

Please Use This Circuit

Online Component Shoppe
http://www.onlinetps.com/
Components at cheap rates in India

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say2paul

sashijoseph

Sat Jun 28 2008, 11:47AM

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Have you provided a proper power-on reset ckt?
Is your xtal close to the micro's pins?

The code is ok.Try increasing the delay 2 or 3 folds.

Let there be music........

This post has been thanked 1 time

say2paul

۞ TPS ۞

Sat Jun 28 2008, 12:00PM

Registered Member #2712

Joined: Tue Jul 31 2007, 12:06AM

Posts: 470
Thanked 67 times in 57 posts

Online Component Shoppe
http://www.onlinetps.com/
Components at cheap rates in India

say2paul

Sat Jun 28 2008, 12:04PM

Registered Member #8461

Joined: Tue Jun 17 2008, 10:56AM

Posts: 123
Thanked 6 times in 6 posts

Thanks TPS and sashijoseph, I dont have the required capacitor for reset circuit right now. I will get it in the morning and will test the circuit and let you know.

And TPS that a lot for the Breadboarg diagram

say2paul

Sun Jun 29 2008, 08:16AM

Registered Member #8461

Joined: Tue Jun 17 2008, 10:56AM

Posts: 123
Thanked 6 times in 6 posts

Thanks its working fine now. The power on reset circuit really worked!

P.S. I noticed that the blinking of Led starts after 1-2 seconds I supply the power to the circuit, might be because of 10uF 63V capacitor.