"please iam confuse "

But I thought you were Enjen Jaenal Abidin!! OK no offense just kidding...

Well from your statement, it does appear that you have not FULLY understood the conversion process. To read from ADC 0808 these are the steps:

1. Apply a clean and good 500 kHz clock

2. Tie the Start and ALE pins and apply a high going pulse of at least 100nS. OK for your case something like 1 or 2 microsecond is fine.

3.Ensure that your analog input is stable after the above pulse time.

4.Keep watching for the EOC pin to go high.

5. When it goes high, read read the output data.

It can't get simpler than this for a start. If you want to drive the ADC0808 to its limits, then grab the data sheet, see the clock limits, minimum pulse times etc.

And finally dont forget to...Enjoy.

Raghu