COE4OI5Engineering Design

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Course Outline

• Design process, design of digital hardware

• Programmable logic technology

• Altera’s UP2 and UP3 boards

• Nios II soft core processor and system on a programmable chip

• Using VHDL for synthesis of digital hardware (including macrofunctions and primitives)

• UP3core library functions (VGA, mouse, keyboard interfaces)

• Design examples

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Project

• Students are supposed to complete a project in groups of two

• Every group can choose the subject of their project

• A typical project should involve the design of a digital system (e.g., FIR filter, a robot control system)

• The design should be entered into CAD tool (e.g., Quartus) using VHDL and be simulated to make sure it meets the specified requirements

• A hardware implementation of the project using the UP2 or UP3 boards available in the lab is required.

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Students’ responsibilities for the project

• Get a pass-card for the lab

• Form groups

• Choose a project

• Actively engage in work on the project

• Prepare a project proposal

• Prepare a progress report

• Prepare a final report

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Lab location, time and facilities

• Lab: ITB-155

• Lab hours: Monday, Tuesday, Wednesday, Thursday, Friday 2:30 to 5:30

• Student can use the lab facility for their projects at additional time: Monday-Thursday 7:30 AM- 11:00 PM, Friday 7:30 AM-9:00 PM, Saturday and Sunday 10:00 AM-10:00 PM

• The door to the lab has a card sweep lock

• This is the only course using the ITB-155

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Suggestions and requests • Start working on the project as soon as possible• Partition your project into modules and implement and test

each module separately• Do not take the UP3 boards out of the lab• A limited number of UP2 boards are available for students to

sign out (if their project require e.g., for a robot project). These boards will be handed on a first come first serve basis.

• Do not play with equipment not related to this course which is in the lab

• Do not drink or eat in the lab• Do not login on a computer and leave it idle • The lab has video surveillance

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CD -ROM

• Contains the Quartus software from Altera.

• Contains the UP2 and UP3 manuals (in booksoft/chap2)

• Contains the UP3core library functions (in booksoft/chap5 directory)

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Definition of Engineering Design

• The process of devising a system, component, or process to meet desired needs

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Required product

Design specifications

Initial design

Simulation

Design correct?

Redesign

Prototype implementation

Testing

Meets specifications?

Finished product

Minor errors?

Make corrections

No

Yes

No

Yes

Yes

No

The development process

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Design Process• Define specifications: essential features of the product are

identified.– Specifications must be tight enough to ensure that the developed

product will meet the general expectations, but not be unnecessarily constraining.

• Initial design: is generated from the design specifications– This step is usually performed by a human designer.

– It requires considerable design experience and intuition.

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Design Process• Simulation: CAD tools are used to simulate the behavior of

the initial design to determine whether the obtained design meets the required specifications.

• If errors are found appropriate changes are made and verification is repeated through simulation.

• Usually all except subtle problems are discovered in this way.

• When simulation indicated that the design is correct, a prototype of the product is constructed.

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Design Process• The prototype is thoroughly tested for conformance with the

specifications.

• Minor errors are often eliminated by making small corrections directly on the prototype.

• In the case of large errors, it is necessary to redesign the product.

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Design of digital hardware

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Design interconnection between blocks

Functional simulation of complete system

Correct?

Physical mapping

Timing simulation

Correct?

Implementation

No

Yes

No

Yes

Design one block Design one block

Partition

Design conceptA

B

C

D

Figure 1.6 Design flow for logic circuits

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Development of a complex digital hardware

Implementation

Finished

Build prototype

Testing

Correct?

Modify prototype

No

Yes

Minor errors?

Yes

Go to A, B, C, or D

No

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Design of digital hardware• A common way of dealing with complexity in digital

hardware is to partition the circuit into smaller blocks and design each block separately.

• Having successfully designed all blocks, the interconnection between blocks must be defined.

• The complete circuit is simulated and errors are corrected

• Errors caused by incorrect connections: connections are redefined (path C)

• Some blocks have not been designed correctly: erroneous blocks are redesigned (path B)

• Some functionality missing: incorrect partitioning (path A)

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Design of digital hardware• Physical mapping: physical location of each chip on the board

and wiring pattern– CAD tools are relied on

• Does the physical layout affect the performance of the circuit (even though the functional behavior of complete system is correct)?

• Physical wiring introduce resistance and capacitance. It may have an impact on the speed of operation.

• Timing simulation is used to check the performance of the circuit after wiring.

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Design of digital hardware• Having completed timing simulation a prototype of the circuit

is implemented.

• The prototype is tested.

• Minor errors are corrected on the prototype.

• Large problems require a redesign.

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CAD tools

• A CAD system has tools for performing the following tasks:– Design entry

– Initial synthesis

– Functional simulation

– Logic synthesis and optimization

– Physical design

– Timing simulation

– Chip configuration

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Design conception

Truth table VHDLSchematic capture

Simple synthesis Translation

Merge

Boolean equations INITIAL SYNTHESIS TOOLS

DESIGN ENTRY

Design correct?

Logic synthesis, physical design, timing simulation

Functional simulation

No

Yes

The first stages of a CAD system

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Design conception

Design correct?

Chip configuration

Timing simulation

No

Yes

Design entry, initial synthesis, and functional simulation

Physical design

Logic synthesis/optimization

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CAD tools

• The starting point in the process of designing a digital circuit is the conception of what the circuit is supposed to do and the formulation of its general structure.

• This step is done manually. The rest is done by CAD tools.

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CAD tools• Design entry: a description of the circuit being designed

should be entered into CAD system

• Different ways of doing this:– Truth tables

– Schematic capture

– Hardware description languages

• Initial synthesis: produces a network of logic gates

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CAD tools• Functional simulation: is used to verify the functionality of

the circuit based on input provided by the designer

• This simulation is performed before any optimization and propagation delays are ignored.

• Goal: validate the basic operations of the circuit

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CAD tools• Logic synthesis and optimization: produces an equivalent but

better circuit

• The measure of what makes one circuit better depends on the needs of a design project and the technology chosen for implementation

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CAD tools• Physical design (layout synthesis): how to implement the

circuit in the target technology• This step consists of placement and routing• Placement: where in the target device each logic function in

the optimized circuit will be realized• Routing: which wires in the chip are to be used to realize the

required interconnections

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CAD tools• Timing simulation: determines the propagation delays that are

expected in the implemented circuit

• Timing simulation: ensures that the implemented circuit meets the required performance

• Some of timing errors can be corrected by using the synthesis tool

• If the logic synthesis tool cannot resolve the timing problem, it is necessary to return to the beginning of the design flow to consider other alternatives

• Final step: configure the target chip to implement the circuit

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Summary

• Design and development process

• Design of digital hardware

• CAD tools

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Design concept

Successful design

Initial design

Simulation

Design correct?

Redesign

No

Yes

The basic design loop