[51] AT89C51 Port pins output issue

[manumj4]

HI
Im using at89c51 mcu for controlling relay, that circuit is working fine but when i am reconnect the power supply port pins are giving pulse output instead of constant output(5v). if i give hardware reset again it is working fine...

 

[FvM]

Either you are triggering a regular program action (check your code how it's possible) or the power-on reset isn't working properly (check your circuit).

 

[manumj4]

Either you are triggering a regular program action (check your code how it's possible) or the power-on reset isn't working properly (check your circuit).

Actually when im powering up the circuit is working fine, when im reset the power the port pins are not working until i give hardware reset...

FYI... before tat i used P89V51RD2 mcu in this setup tat time it was working fine...

 

[manumj4]

Hi
you are correct, i did some mistake in reset circuit... now my circuit is working fine..
thank u...