EE 475, Computer Architecture, considers the design of digital computers. This page describes some essential VHDL needed for EE 475. We use VHDL for building hardware - hence we concentrate on the synthesis subset of the language. VHDL can also be used to accurately model digital systems. These simulation models can be extremely complex and are beyond the scope of this course.
Every digital circuit has inputs and outputs.
Ports, the inputs and outputs of a circuit have a mode. Ports of IN can only be read, trying to write, or assign a value will result in a error. OUT can only be written, attempting to read the value will result in an error. Don't use it. VHDL literals are not case sensitive.