Hello all attached is the code modeled in vhdl
for ADC 0804 IC from national semiconductor.
can be used microprocessor interfacing like with 8080A and 6800 also with 8051 micro controller and so on has many applications
check this pdf file for more applications==> http://www.sonsivri.com/forum/index.php?action=dlattach;topic=26284.0;attach=4874verilog version
for the same is ==>http://www.sonsivri.com/forum/index.php?topic=26284.0
just modify the attached file extension from .txt to .vhd and you can use it with altera, xilinx, modelsim , cadence, and so on....