Design Process Tutorial

PwnHero COE 758 Design Tutorial Page 1 COE 758 - Design Process Tutorial I. Introduction This tutorial describes a formal design process for the creation of digital systems. The aim of this design process is to provide a systematic approach to the design of digital components, beginning with a design specification, and ending with a working component which meets all specifications. The process being described limits itself to digital designs. Throughout the document, a simple example circuit is used to better illustrate each step. The process begins with the introduction of Design Specifications, and their analysis. Based on these specifications, a Symbol for the component is created. This describes the system’s inputs and outputs, and all interfaces to the surrounding environment. Once the symbol is complete, a block diagram is constructed, based on the required functionality of the system. The elements of the block diagram are then implemented as VHDL code, and integrated into a single design. This design is then implemented as a circuit and testing and verification can take place. Each stage will be described in more detail in the following sections. To recapitulate, the steps of the design process are: 1. Specification Analysis. 2. Symbol Creation. 3. Block Diagram and Behavioural Description Creation. 4. HDL Implementation. 5. System Integration. 6. Synthesis and circuit implementation. 7. Test and Verification. II. Design Specifications Design specifications are the starting point of any design. These are the requirements that the digital circuit being implemented must address. Such specifications come in two types: Functional and Technical specifications. Functional specifications describe the functionality that a given circuit must implement. They describe the required behaviour of the circuit. Technical specifications describe specific technical aspects associated with the circuit as well as surrounding systems. They augment the functional specifications, by accurately describing the parameters of the circuit behaviour. EXAMPLE: Consider the creation of a Reset Block, a circuit which monitors an external reset signal, and generates three auxiliary reset signals which will be used in other designs. This circuit example will be used as an illustrative example for the remainder of this document. Below are listed the functional specifications for the circuit. PwnHero.com