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Can AT89C2051 be reprogrammed after short circuit ?

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Krishna Patil

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As i referred to datasheet of AT89C2051 i found it is reprogrammable. I had programmed this microcontroller (Mc) and it was working fine, i was connecting L293D( motor driver) to it , may be with wrong connection, something happened , Mc is getting heated up within few seconds after connecting power and across voltage rails , voltage drops below 3V , so what might have happened ? i think it is short circuit . Is that Mc dump now ? or can it be reprogrammed even after short circuit ?

I have used 7805 , it has short circuit protection , it must go foldback, but why Mc is damaged ?
 

7805 does have a short circuit protecion, but according to datasheet from Fairchild Semiconductor it limits current to 250 mA. In that case you could've burned your MCU without problem.
 

Short circuiting the pins of microcontroller does not mean a short circuit to the 7805. It will supply voltage as long it is heated up and protection circuit in 7805 starts working..

You can not reprogram the microcontroller if some pins are damaged.
 
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    tpetar

    tpetar

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poorchava said:
7805 does have a short circuit protecion, but according to datasheet from Fairchild Semiconductor it limits current to 250 mA. In that case you could've burned your MCU without problem.
Click to expand...

What is Input voltage ?
Dissipation power of 7805 (Vi-Vo/I) ?
What is power of motor?

For me sound like that motor pull to much current from L293D.

L293D can supply 600mA continuous, and 1A in peak.

https://www.pobot.org/IMG/pdf/l293.pdf

Example of connection:
l293d.gif


I complete agree with nandhu015 post.
 

I forgot to add: not always shorting the chips output will damage completly. Sometimes it happens that only one pin or one port gets damaged. In such case is sometimes is possible to program the chip again (of course given that the pins needed for programming weren't amongst those, which were damaged)
 

When you say the chip heats up when powered and the volatge drops to 3V, its sure that some internal short prevails and thus you cannot re-program the chip.
Cheers
 

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