problem in reset circuit for 89s52

[hassan ali]

hi,.....sorry for my English

i have build up my own project but there is a problem, always when i power up my circuit the controller doesn't work from the first time it needs a reset button and it hang up more times i don't know why it's hang up i change the controller with another but the problem is still exists , and i want to know the problem in reset circuit , please help me in short time.

 

[ckshivaram]

check the reset circuit
**broken link removed**
use 10k or the 8.2K as shown in figure
or post your circuit..

 

[hassan ali]

i build up this circuit but the controller still hang up , how can i fix this problem??????
also , why the program doesn't work from the first time ??????

 

[ckshivaram]

check the voltage at pin 9 when you press the switch.. how much voltage are you getting... put a 0.1uf or 100nf capacitor at the supply and ground points of controller....

 

[hassan ali]

when i pressed on reset switch the voltage on pin 9 is equal to 5.12volt!!!!!!!!!!!!!!!!!

 

[ckshivaram]

can you put your circuit or replace the controller and try it.......

Also please check for any spikes or spurious or noise in the 5V supply.......

 

[gun]

1) yes there may be problem in reset circuit.
2) please check 5v powersupply it should not rock solid

 

[dimas_lilik]

I think your 89S52 broken. I always make this schematic NO Problem.