Introduction to FPGA

Created & Presented By Ali Masoudi

For Advanced Digital Communication Lab (ADC-Lab)

At Isfahan University Of technology (IUT)

Department Of Electrical & Computer Engineering

Content

FPGA Advantages FPGA Structures Useful Tools HDL – Verilog

FPGA Advantages

Designing with FPGA: Faster, Cheaper Ideal for customized designs

Product differentiation in a fast-changing market Offer the advantages of high integration

High complexity, density, reliability Low cost, power consumption, small physical size

Avoid the problems of ASICs high NRE cost, long delay in design and testing increasingly demanding electrical issues

FPGA Advantages

Very fast custom logic massively parallel operation

Faster than microcontrollers and microprocessors much faster than DSP engines

More flexible than dedicated chipsets allows unlimited product differentiation

More affordable and less risky than ASICs no NRE, minimum order size, or inventory risk

Reprogrammable at any time in design, in manufacturing, after installation

User Expectations Logic capacity at reasonable cost

100,000 to a several million gates On-chip fast RAM

Clock speed 150 MHz and above, global clocks, clock management

Versatile I/O To accommodate a variety of standards

Design effort and time synthesis, fast compile times, tested and proven cores

Power consumption must stay within reasonable limits

Field Programmable Device

Basic Section of FPD: Logical Block Routing (Switch Matrix) Input Output Block

More Advanced FPD Contains: On-chip Memory Embedded Processor Clock Management High-Speed Transceiver

FPGA Structures

Basic Lookup Table (LUT)

FPGA Structures

Synchronous Look-UP

FPGA Structures

Routing Local ( Local connections )

CLB to CLB CLB to IOB

Global ( Span all section of chip ) Global Set/Reset Global Tri-Sate Clock

FPGA Structures

FPGA Structures Configurable Logic Block (CLB)

Two identical slices in each CLB Two LUT in each slice

RAM Blocks Xilinx core generator Synplify ( Best Synthesizer in the world )

CLK - Delay Locked Loop (DLL)

CLB Slice

CLK - DLL

In dealing with a DDR-RAM , CLK-DLL can multiply frequency of CLK by factor 2 , by generating the same signal with 180 degree shift in phase .

Global Clock Distribution

Spartan-II FPGA Family

Spartan-II FPGA Family

Design Flow

Simulation a) Functional b) Timing c) Gate Level

Design Flow

Synthesis HDL Code to Netlist conversion

Mapping Digital Circuit Element to Technology Element

Mapping Place & Route

Sitting place for each element of circuit?

Design Constraints

Combinational: PAD to PAD

Sequential

Basic Sequential Paths: PAD to clock/Register Register to Register Clock/Register to PAD

ISE Implementation Flow

Translate: ngdbuild

Putting all thing together, so that we need all part of project

Inputs: Project synthesized EDIF file UCF constraints file Core’s .ednfile

Output: Native Generic Database (internal format) Complete hierarchy .ngdfile

Map

MAP Operation: Map the generic form to device Make necessary optimization, eliminate

unnecessary logic Estimate resource usage, just % (110%!) Check the connection Input: .ngdfile Output: .map file

PAR (Place & Route)

PAR Operation: Place and Route all the logics Some of placing process done in previous steps Overused area give error in this section Input: Unrouted.ncd Output: Routed.ncd

Bit File Generation & Device Programming

Recommended Directory Structure

Recommended Tool Set

Design Entry HDL Designer / Active HDL / Text Pad

Simulation ModelSim / Active HDL / NC Sim

Synthesis XST / Amplify / Synplify

Place & Route ISE

HDL – Verilog

Verilog Syntax is almost similar to language C , so that learning & understanding of Verilog is very simple .

It’s Module-based like C that is Function-based .

For more information on Verilog , look at 1) Verilog VHDL Golden Reference Guide

2) Verilog Quick Start