Hello Kostas,
I redrew your schematic so that other could understand what you are trying to do. Hope this clears up your problem. I hope I faithly reproduced the ASCII drawing. Let me know if there are any mistakes and I will update the drawing.
Regards,
Charles Bannister

kostas paulidis wrote:
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Hi,i use a circuit in order to observe if a device is under the net of 220 volt.
But ,when i do not have 220v i take an instant sign that i have 220v.Can anybody help me?
The optocoupler TIL 111 ensure the isolation between the net of 220v and 8051.
I have to mention that the output of optocoupler is a pulse current,for this reason i use the capacitor c1 that makes the T1 transistor to have an output of 5v continuity .
i use this rutin with the method of polling.
where i do wrong?

	SETB	P1.2
	MOV	A,P1
	ANL	A,#00000100b
	JNZ	SIG
	CALL	sign_on
	JMP	EXIT
SIG:	CALL	sign_off
EXIT:	END

thank you for any help