ADC0804 interfaced with CPLD

Thank you very much for the reply and advice. On most of the circuit diagrams I look at the RC network used to clock the ADC has the following value: C=150 pF and R=10 kohm. I am using the matrix multimedia CPLD target board which has a 25 MHz crystal. I have reduced the clock frequency to 625 KHz as read that is the most frequently speed used. I have followed the steps given on the data sheet for starting the conversion and reading the value. No success yet unfortunately. Does what I wrote see correct to you?