VERILOG BASICS

Design Methodology:

There are two basic types of digital design methodologies: a top-down design methodology and a bottom-up design methodology.

In a top-down design methodology, we define the top-level block and identify the sub-blocks necessary to build the top-level block. We further subdivide the sub-blocks until we come to leaf cells, which are the cells that cannot further be divided. Figure below shows the top-down design process.

Top Down Approach:

              

Bottom Up Approach:

          

Behavioural or Algorithmic level:

This is the highest level of abstraction provided by the verilog HDL. A module can be implemented in terms of desired design algorithm withouth concern for the hardware implementation details. Designing this level is very similar to “C” programming.

Data flow level:

At this level ,module is designed by specifying the dataflow. The designer is aware of how data flows between hardware registers and how the data is processed in the design.