Digital System Design with VHDLIntroduction to digital system designStart the session with an introduction to DIGITAL ELECTRONICS.

● Review of Binary system and Boolean algebra● Review of Logic gates, Multiplexer (combinational

circuits), Flip Flop, Registers, Counters (sequential circuits), etc.

● Discrete components● Digital ICs● Fab devices

➔ Microprocessor (CPU)Wrist watch to satellite vehicle

➔ Microcontrollers (SoC)(Interactive questions related to De Morgan's Law,

Universal gates, Digital circuits, Digital ICs etc.)

Digital System Design with VHDLProgrammable Logic Devices (PLD)● To build reconfigurable digital circuits● Field devices● General purpose chip for implementing logic

circuits● Developed by Rone Cline from Signetics (Later

Philips, now Xilinx)

Digital System Design with VHDL

Programmable Logic Devices (PLD)

Different types :

1. ROM (ASIC)➢ Not as memory➢ m input lines (address lines), n output lines

(data lines)➢ 2m Boolean functions allows 2n logic

functions produced at output

Digital System Design with VHDLProgrammable Logic Devices (PLD)

Basic ROM Structure:

Digital System Design with VHDLProgrammable Logic Devices (PLD)

Basic ROM Structure:● The logic array are of mask, fusible wires or

special charge-storage mechanism● Along with flip flops sequential logic can be

implemented

Digital System Design with VHDLProgrammable Logic Devices (PLD)

2. Programmable Logic Array (PLA):● More flexible than ROM● Internal decoder is replaced with AND array

Basic PLA structure:

Digital System Design with VHDLProgrammable Logic Devices (PLD)

3. Programmable Array Logic (PAL)● Economical and easy to program ● Same as PLA, but AND array is only

programmable● All these PLDs are available with Flip flops● Lattice Semiconductors, Cypress

Semiconductors, Atmel , Xilinx, Altera, Texas Instruments are some vendors of PLDs

Digital System Design with VHDLProgrammable Logic Devices (PLD)

4. Complex PLD (CPLD)● ROM, PLA and PAL are not flexible for

sequential and more complicated combinational digital circuit design

● Upto 10,000 logic● Contains many PAL blocks called macro cells

Digital System Design with VHDLProgrammable Logic Devices (PLD)

Typical structure of macro cells:

Digital System Design with VHDLProgrammable Logic Devices (PLD)Structure of typical CPLD:

Digital System Design with VHDL

Programmable Logic Devices (PLD)CPLD:● Typical CPLD consists 2 to few 100 PAL blocks

Digital System Design with VHDLProgrammable Logic Devices (PLD)

CPLD:

Some CPLD vendors and the devices are:● Altera MAX 7000 Family● AMD Mach Family● Lattice Family● Cypress Flash 370 Family● Xilinx XC9500 Family

Digital System Design with VHDL

Programmable Logic Devices (PLD)

Field Programmable Gate Array (FPGA):● For large number of logic circuits● More than 10,000 logic

Digital System Design with VHDLProgrammable Logic Devices (PLD)

Field Programmable Gate Array (FPGA):

Digital System Design with VHDLProgrammable Logic Devices (PLD)

Field Programmable Gate Array (FPGA):

Some vendors are:● Xilinx● Actel● Atmel● Lattice● Altera● Quick Logic

Digital System Design with VHDLElectronic Design Automation (EDA) Tools:● Software tools for designing electronic system

like PCBs, ICs, PLDs, CPLDs, FPGAs, etc.➔ Simulation, analysis and verification,

manufacturingSome vendors of EDA softwares are:

● Cadence Design System● Cadsoft● Impulse Accelerated Technologies● Labcenter● Mentor Graphics

● National Instruments Electronics Workbench Group

● Synopsys● Visionics

Digital System Design with VHDLHardware Description Language (HDL)● Used to model the intended operation of a

piece of hardware● To describe the architecture and behavior of

digital electronic systemVarious softwares:

➔ ABEL (Advanced Boolean

Expression Language)➔ AHDL (Altera HDL)➔ C to Verilog➔ Impulse C➔ JHDL (Java HDL)

➔ RHDL (Ruby HDL)➔ System C➔ System Verilog➔ Verilog➔ VHDL

Digital System Design with VHDLSyllabus

Module 1:

✔ Design flow of digital system✔ Introduction to EDA and HDL, Simulation etc✔ Basics of VHDL

Module 2:

✔ VHDL syntax and statements✔ VHDL models for basic combinational and sequential circuits

Module 3:

✔ VHDL model for digital circuits✔ State machines and its VHDL model ✔ Synthesis✔ Designing of CPLD and FPGA

Digital System Design with VHDLReferences:

1. Zainalabedin Navabi, VHDL: Analysis and modeling of digital systems (For all lectures and tutorials)

2. Perry D. L, VHDL Programming by Example.(Some lectures all tutorials)

3. Roth C. H., Digital System Design Using VHDL (Some lectures and some tutorials)

4. Mano M. M. and Ciletti M. D, Digital Design (Some lectures and some tutorials)

5. Pedroni V. A., Circuit design with VHDL. (Reading)

6. Peter J. Ashenden, The Designer's Guide to VHDL (Reading)

7. Sudhakar Yalamanchili, VHDL Starter's Guide (Reading)

8. J.Bhasker, VHDL Primer(Reading)

9. Wakerly J. F, Digital Design – Principles and Practices (Reading)