This reminds me of the chess masters that play entire games of chess against people without ever looking at a board.

I will take a stab at the code with no clue of your connections:

"sorry for the confusion.
here is the code of my adc interfacing prog."

This doesn't clear up the confusion..


"is it correct?

mov p0,#0ffh
clr p3.3 ; select channel zero"

All three pins ADD A, ADD B, and ADD C have to be low for channel 0. Not just one. Depends on how you have it wired up.

"clr p3.4
setb p3.4 ; enable ALE"

The example waveform shows ALE rise, then START rise to clock in address and reset SAR register (uh oh - this couldn't be the source of the new respiratory virus could it? And it was bottled up in the ADC0808 all this time...). Strobing ALE alone does nothing.


"setb p3.0 ;enable soc
nop
clr p3.0"

Starts conversion, but didn't latch in the address.


"here: jnb p3.6,here ;wait till conversion ends.
here1: jb p3.6,here1"

You don't know the state of EOC right here! It be either high or low. If EOC is low going into this, it will loop forever here.


"setb p3.2
clr p3.2 ;output enable"

Why strobe OE?

"mov a,p0 "


This code is not sound. Try using a fixed delay. Less to go wrong. Or in my opinion, grab a more modern part.

- Lee