AT89C52 INTERRUPT Problem- URGENT!!!!!!!!!

[shigha]

I was using interrupt driven LCD interface with AT89C52. My code was working properly and everything was right and I got the output. But to fit my pcb in to the box, I have to desolder lcd and solder it once again. But now checking, its not working. The lcd is just displaying black boxes on the first row. Eventhough interrupt is given, its not displaying anything on lcd. I have checked the status of other pins to see whether microcontroller is initialised. And status of other pins are right and everything is working. Then why is that the microcontroller is not working with interrupts? lcd is only giving black boxes on first line.


Can there be any problem that code in microcontroller can get corrupted??
But how then other pins status are right?


In the middle, I have given 6v as power supply. Can it create a problem?Can it make the code corrupt?
Is the lcd bad?
its urgent........... please do help me

 

[firevsice55]

if the software is working fine, as you are saying..
Check the hardware connections.. there could be a mix up while resoldering..

 

[aameer]

if you are using 2x16 LCD check 4th pin &6th pin connected to micro controller. and check in your program whether they mentioned exactly.
If everything is rightly connected as per your program it should come.
IF not change the crystal and check.

 

[tushki7]

Greetings
lcd is only giving black boxes on first line. >>> Shows lcd is working properly.
IMPORTANT STEP : Recheck your lcd pins and connections with micro-controller carefully.
Re-soldering usually creates problems like Leakage.
There is only .1% chance that your code might get corrupted. check all the data pins(interfaced to lcd) of your micro controller using led.

What do you mean by In the middle, I have given 6v as power supply ???

Good Luck

 

[shigha]

To tushki7, I have rechecked and its all working but still Iam not getting anything on screen except black boxes on first line. My +5v power supply was not working so I have to give +6v. But later I gave another +5v power supply from regulator 7805. Now also, its not showing anything except black boxs

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To firevsice55, I checked the hardware connections, there is no problem but still Iam not getting output

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To aameer, I was getting the output before desoldering. So it cant be any changes with program. Is it a necessary that i should change the crystal?

 

[tushki7]

I already told you if you see black boxes on first line this shows your connections to lcd are fine.
Have you correctly soldered micro controller with proper vcc and ground connections? check 31st pin must be connected to VCC and crystal is connected properly with capacitors and grounded properly.
Do not apply pull-up resistors on interrupt pins!!
Have you checked your micro controller data pins and other 3 pins(cs, wr, rd) tie Led's to it and check whether all led's blinks or glow at times.
Reprogram your micro controller without interrupt, sometimes keil(if you are using so) does not program interrupt related programs correctly, use licensed keil.
Always use busy pin of LCD.

Good Luck

 

[shigha]

thanks, i think it mit be some leakage with hardware connections..........

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thanks, i think it mit be some leakage with hardware connections..........

 

[aameer]

So did you got the output.