VHDL Code Examples for Flip Flop, Serial to Parallel Converter, 4 bit Counter, State Machine, and ADDER. VHDL Code Examples. VHSIC (Very High Speed Integrated Circuits) Hardware Description Language IEEE-1076. This is just a quick reference of some short VHDL code fragments. Above each code segment is a circuit which represents the fragment. In most cases the Process, and end of Process.