The following paper has been conceived to deal with the contents of some lectures aimed at enhancing courses on digital electronic, microelectronic or VLSI systems. Those lectures show how to use a hardware description language (HDL), such as the VHDL, to specify, design and verify a custom microprocessor. The general goal of this work is to teach how to handle the design of a complete digital system, using a commercially important HDL, from specification to testing. From a pedagogical point of view, this is very important since it helps students get used to a design flow commonly accomplished within semiconductors and microelectronics industries. (Contains 10 figures.)