© 2003 Xilinx, Inc. All Rights ReservedFor Academic Use Only

Xilinx Design FlowFPGA Design Flow Workshop

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Objectives

After completing this module, you will be able to:• List the steps of the Xilinx design process• Implement an FPGA design by using default software options

Xilinx Design Flow 3 - 3 © 2003 Xilinx, Inc. All Rights ReservedFor Academic Use Only

Outline

• Overview• ISE• Summary

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Translate

Map

Place & Route

Xilinx Design Flow

Plan & Budget HDL RTLSimulation

Synthesizeto create netlist

FunctionalSimulation

CreateBit File

Attain Timing Closure

TimingSimulation

Implement

Create Code/Schematic

Xilinx Design Flow 3 - 5 © 2003 Xilinx, Inc. All Rights ReservedFor Academic Use Only

Design Entry

• Plan and budget• Two design-entry methods: HDL or schematic

– Architecture Wizard, CORE Generator™ system, and StateCAD are available to assist in design entry

• Whichever method you use, you will need a tool to generate an EDIF or NGC netlist to bring into the Xilinx implementation tools

– Popular synthesis tools: Synplify, Precision, FPGA Compiler II, and XST• Simulate the design to ensure that it works as expected!

Plan & Budget Create Code/Schematic

HDL RTLSimulation

Synthesizeto create netlist

FunctionalSimulation

. . .

Xilinx Design Flow 3 - 6 © 2003 Xilinx, Inc. All Rights ReservedFor Academic Use Only

Xilinx Implementation

• Once you generate a netlist, you can implement the design

• There are several outputs of implementation

– Reports– Timing simulation netlists– Floorplan files– FPGA Editor files– and more!

Translate

Map

Place & Route

Implement

. . .

.

.

.

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What is Implementation?

• More than just “Place & Route”• Implementation includes many phases

– Translate: Merge multiple design files into a single netlist– Map: Group logical symbols from the netlist (gates) into physical

components (slices and IOBs)– Place & Route: Place components onto the chip, connect them, and

extract timing data into reports• Each phase generates files that allow you to use other Xilinx tools

– Floorplanner, FPGA Editor, XPower

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Timing Closure

• The Timing Closure Flow is a recommended method for helping designs meet their timing objectives

• Details on each part of the flow are discussed in this course and in the Designing for Performance course

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Download

• Once a design is implemented, you must create a file that the FPGA can understand

– This file is called a bitstream: a BIT file (.bit extension)

• The BIT file can be downloaded directly to the FPGA, or it can be converted into a PROM file, which stores the programming information

Xilinx Design Flow 3 - 10 © 2003 Xilinx, Inc. All Rights ReservedFor Academic Use Only

Outline

• Overview• ISE• Summary

Xilinx Design Flow 3 - 11 © 2003 Xilinx, Inc. All Rights ReservedFor Academic Use Only

What is ISE?

• Graphical interface to design entry and implementation tools

– Access to synthesis and schematic tools

• Including third-party synthesis tools

– Implement your design with a simple double-click

• Fine-tune with easy-to-access software options

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WebUpdate

• Automatically checks for Service Packs on the web• Alerts you when an update is available• Supports PC platform only

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Creating a Project

• Select File New Project

• New Project Wizard guides you through the process

– Project name and location

– Target device– Software flow– Create or add

source files

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Creating and AddingSource Files

• To include an existing source file, double-click Add Existing Source

• To create a new source file, double-click Create New Source and choose the type of file

– HDL file– IP– Schematic– State diagram– Testbench– Constraints file

Xilinx Design Flow 3 - 15 © 2003 Xilinx, Inc. All Rights ReservedFor Academic Use Only

Implementing a Design

• To implement a design:– In the Sources in Project window,

select the top-level source file • HDL, schematic, or EDIF,

depending on your design flow– In the Processes for Source window,

double-click Implement Design

Xilinx Design Flow 3 - 16 © 2003 Xilinx, Inc. All Rights ReservedFor Academic Use Only

Implementation Status

• ISE will run all of the necessary steps to implement the design

– Synthesize HDL code– Translate– Map– Place & Route

• Progress and status are indicated by icons– Green check mark ( ) indicates that the

process was completed successfully– Yellow exclamation point ( ! ) indicates

warnings– Yellow question mark ( ? ) indicates a file

that is out of date– Red “X” indicates errors

Xilinx Design Flow 3 - 17 © 2003 Xilinx, Inc. All Rights ReservedFor Academic Use Only

Simulating a Design

• To simulate a design:– In the Sources in Project window,

select a testbench file – In the Processes for Source window,

expand ModelSim Simulator – Double-click Simulate

Behavioral Model or Simulate Post-Place & Route Model

• Can also simulate after Translate or after Map

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Sub-Processes

• Each process can be expanded to view sub-tools and sub-processes

– Translate• Floorplan• Assign Package Pins

– Map• Analyze timing

– Place & Route• Analyze timing• Floorplan • FPGA Editor• Analyze power• Create simulation model

Xilinx Design Flow 3 - 19 © 2003 Xilinx, Inc. All Rights ReservedFor Academic Use Only

Hierarchical Simulation Netlists

• Create separate simulation netlists and SDF files for each level of design hierarchy

– Simplifies timing verification– Allows you to re-use testbenches from behavioral simulation

• Hierarchy must be maintained during synthesis• Use the KEEP_HIERARCHY attribute in UCF file• For more information, see Answer #17693

Xilinx Design Flow 3 - 20 © 2003 Xilinx, Inc. All Rights ReservedFor Academic Use Only

Program the FPGA

• There are two ways to program an FPGA

– Through a PROM device• You will need to generate

a file that the PROM programmer will understand

– Directly from the computer• Use the iMPACT

configuration tool

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Outline

• Overview• ISE• Summary

Xilinx Design Flow 3 - 22 © 2003 Xilinx, Inc. All Rights ReservedFor Academic Use Only

Review Questions

• What are the phases of the Xilinx design flow?

• What are the components of implementation, and what happens at each step?

• What are two methods used to program an FPGA?

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Answers

• What are the phases of the Xilinx design flow?– Planning and budgeting, create code or schematic, RTL simulation,

synthesize, functional simulation, implement, timing closure, timing simulation, BIT file creation

• What are the components of implementation, and what happens at each step?

– Translate: merges multiple design files into one netlist– Map: groups logical symbols into physical components– Place & Route: places components onto the chip and connects them together

• What are two methods used to program an FPGA?– PROM– Xilinx iMPACT configuration tool

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Summary

• Implementation means more than place & route

• Xilinx provides a simple “pushbutton” tool to help you through the Xilinx design process

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Where Can I Learn More?

• Complete design flow tutorials– http://support.xilinx.com Documentation Tutorials

• On the phases of implementation– http://support.xilinx.com Software Manuals Development System

Reference Guide• On hierarchical simulation netlists

– http://support.xilinx.com Answer #17693• Configuration Problem Solver

– http://support.xilinx.com Problem Solvers Configuration Problem Solver