AT89C51 START PROBLEM ..PLEASE NEED HELP..

[cool]

hi, 

i am stuck in a middle of a problem in my final year project..

i am using an at89c51 microcontroller. in my project..

the problem im facing is that my microprocessor starts working after some time..after connecting to a 5V supply..

 

the L.C.D i connected to the glows but it doesnt display anything..

 

but after some time(say about 10 minutes) and after presssing reset button repeatedly.. it starts working perfectly… without any trouble…

 

my circuit is ok,,as it works fine after some time…

 

i dont have any idea wat is causing this…

 

is this a problem with microcontroller or is there a problem with something else….

 

please guide me im unable to complete my project…

[anurudh tiwari]

  take a multimeter and check the directly vcc and ground pin of your microcontroller after switching the supply….if it gives the correct volatage…. then change your oscillator connected pin 18-19…

[Harsh Pandya]

Firstly you need to understand , a controller works at faster speed compared to lcd so before initializing LCD you need to keep a delay of min 20ms in controller programming.

 

Secondly check foll voltages at controller pins :

 

Vcc – 5V

ALE – 1.68V

PIN 18 and 19 – (around) 2.18 to 2.8 V

 

and then tell me if the problem remains !!!

[Shashank]

check with the capacitor at the reset pin..

[cool]

i checked my program is fine..as it works perfectly..

i am getting 5 volts at vcc 

 

i checked it again and the porblem is just at the lcd…(it doesnt display anything in the start but starts working after some time)

 

i have interfaced a stepper motor with a microcontroller it works well even iff there is nothing on the lcd..

 

so the microcontroller is fine as it is doing its job…but why does lcd cause this problem??

[Mehtab Ali]

may be your lcd have some problem, you try another lcd also if you can post your program so that i can check if there some problem in that

[D.V.G. Krishna]

hi

 

i got the same problem

 

but my guide told me a solution

 

to manually reset the MCU up to 20seconds

 

you need to press the reset switch for not less than 20seconds

 

he said that some times the MCU goes in to sleepmode

 

 

[cool]

thnx ill try this one 

[Author]

Posts