ADC0804 control using VHDL

Discussion in 'Embedded Systems and Microcontrollers' started by jag1972, Dec 10, 2012.

  1. jag1972

    Thread Starter Active Member

    Feb 25, 2010
    Hello All,
    I have been trying to control the ADC0804 using a VHDL code. The aim is to connect an analogue input (potentiometer) to the ADC and interface that with a CPLD.

    I have been studying the conversion and read processes.
    Make chip select low
    Make write low
    Make chip select high
    Wait for INTR pin to go low (implying end of conversion).
    I have managed implement the code for this using the simulator in Altera quartus 2. The target board I am using has a 25 MHz crystal. I have reduced the frequency to just over 600 KHz.
    After each step I have waited for at least one clock cycle, could someone please have a look at the code and let me know if I am on the right track. Is could you please give me some hints how to read the value from the ADC. Thanks in advance.