VHDL
Subject and UNIT: Digital Logic Circuits: Unit V: VHDL
• The listing shows the VHDL structural description for half-adder. In the VHDL description, the entity part is same as that of behavioral description. However, architecture part has two components : declaration and instantiation.
VHDL
Subject and UNIT: Digital Logic Circuits: Unit V: VHDL
The circuit is an AND-OR circuit in which signals A, B, C, D and E are input signals, signal Y is an output signal and signals II and 12 are intermediate signals.
VHDL
Subject and UNIT: Digital Logic Circuits: Unit V: VHDL
• An entity declaration describes the external interface of the entity. It specifies the name of the entity, the names of input/output ports, and the type of ports. The syntax for an entity declaration is as shown below.
Subject and UNIT: Digital Logic Circuits: Unit V: VHDL
• VHDL supports a variety of data types. The type of a variable, signal, or constant determines the operators that are predefined for that object as well as the range of values that it can take on. The VHDL data types can be broadly classified into following five data types :
Signal, Variable, Constant, File
Subject and UNIT: Digital Logic Circuits: Unit V: VHDL
• A data object holds a value or a range of values of a specified type. It is created by means of an object declaration. In VHDL, there are four classes of data objects, signals, variables, constants and file.
with example
Subject and UNIT: Digital Logic Circuits: Unit V: VHDL
There are two types of identifiers in VHDL : • Basic identifiers • Extended identifiers
Behavioral, Dataflow, Structural | VHDL
Subject and UNIT: Digital Logic Circuits: Unit V: VHDL
• In a VHDL or Verilog program, architecture body (VHDL) or the module (Verilog) contains a series of concurrent statements.
Subject and UNIT: Digital Logic Circuits: Unit V: VHDL
• The main components of a VHDL description consists of following kinds of declarations : ■ Package (optional) ■ Entity ■ Architecture ■ Configuration (optional)
necessity, need
Subject and UNIT: Digital Logic Circuits: Unit V: VHDL
• We are familiar with the design of a digital system. The basic steps involved in this process are, a. Specify the desired behaviour of the circuit. b. Synthesize the circuit. c. Implement the circuit. d. Test the circuit to check whether the desired specifications meet.
Digital Logic Circuits
Subject and UNIT: Digital Logic Circuits: Unit V: VHDL
Digital Logic Circuits: Unit V: VHDL : Syllabus, Contents
Introduction to Programmable Logic Devices | Digital Logic Circuits
Subject and UNIT: Digital Logic Circuits: Unit IV: (c) Introduction to Programmable Logic Devices
Digital Logic Circuits: Unit IV: (c) Introduction to Programmable Logic Devices : University Questions with Answers (Long Answered Questions)
Introduction to Programmable Logic Devices | Digital Logic Circuits
Subject and UNIT: Digital Logic Circuits: Unit IV: (c) Introduction to Programmable Logic Devices
Digital Logic Circuits: Unit IV: (c) Introduction to Programmable Logic Devices : Two Marks Questions with Answers