Question

what are the different ways you can represent the exact same design using:

A.  VHDL

B.  state diagrams

C. sequences

Answer 1

1. VHDL can define a design in three different ways or sometimes can say in four ways namely:

(i) Behavioral : Defines the design behavior without any regard to internal description of the design

(ii) Data Flow : Relates output of the design with the inputs

(iii) Structural : Top level module builds upon multiple submodules

(iv) Mixed Mode : Combination of the three listed above

2. State Diagram

(i) Mealy State diagram: input and output shown on transition arcs

(ii) Moore State diagram: transition arc just mentions inputs. output is state dependent

Further different encoding techniques of states like binary encoding, one hot state assigment etc. causes variation in number of states

3. Sequences

Based on hardware like type of flip flops to be used , truth table is built considering excitation equation, characteristics and transition equations.

Also sequencing circuits are used to move the actuator in defined sequence.