242 CHAPTER 6 / NONARITHMETIC COMBINATIONAL LOGIC DEVICES
assist the reader in developing good design practices, the following six-step sequence is
recommended:
Step 1: Understand the device. Describe the function of the device; then clearly
indicate its input/output (I/O) specifications and timing constraints, and con-
struct its block diagram(s).
Step 2: State any relevant algorithms. State all algorithms and/or binary ma-
nipulations necessary for the design. Include a general operations format if
necessary.
Step 3: Construct the truth tables. From step 2, construct the truth tables that
detail the I/O relationships. Truth tables are usually presented in positive logic
form.
Step 4: Obtain the output functions. Map or use a minimization program to