Digital Signal Processing Reference
In-Depth Information
Figure 4.2
Lpm_counter0 MegaWizard edit window.
Special hardware blocks have been designed to support the easy use of the
advanced I/O features found on the FPGA board. They include pushbuttons,
LCD displays, keyboard, mouse, and video output. More details on all of these
FPGAcore functions are provided in Chapter 5. The FPGAcore functions
needed for this tutorial have already been placed in this project's directory.
Several symbols from the FPGAcore library appear in the project library and
are available to be entered in a design.
As an alternative to copying these files to each project's directory, under
Project
Add/Remove Files in Project,
in the left column you can click on
Libraries
and enter another path to an external library such as the FPGAcore
library.
4.3 Browse the Hierarchy
In engineering, the principle of functional decomposition is normally used in
large designs. Complex designs are typically broken into smaller design units.
The smaller design units are then more easily understood and implemented. The
smaller designs are interconnected to form the complex system. The overall
design is a hierarchy of interconnected smaller design units. This also promotes
the re-use of portions of the design.
The current schematic is a view of the top level of the design. In this design,
the problem was decomposed into a module (design unit) or symbol with logic
for a counter and another design unit to display the count. Each symbol also has
an internal design that can be any combination of another schematic,
megafunction, VHDL, or Verilog file.
