Chapter 1 Introduction. Dr. Naim Dahnoun, Bristol University, (c) Texas Instruments 2004 Chapter 1,...

Chapter 1Chapter 1

IntroductionIntroduction

Dr. Naim Dahnoun, Bristol University, (c) Texas Instruments 2004

Chapter 1, Slide 2

Learning ObjectivesLearning Objectives

Why process signals digitally?Why process signals digitally? Definition of a real-time application.Definition of a real-time application. Why use Why use DDigital igital SSignal ignal PProcessing rocessing

processors?processors? What are the typical What are the typical DSPDSP algorithms? algorithms? Parameters to consider when choosing a Parameters to consider when choosing a

DSP processor.DSP processor. Programmable vs ASIC DSP.Programmable vs ASIC DSP. Texas Instruments’ TMS320 family.Texas Instruments’ TMS320 family.


Chapter 1, Slide 3

Why go digital?Why go digital?

Digital signal processing techniques are Digital signal processing techniques are now so powerful that sometimes it is now so powerful that sometimes it is extremely difficult, if not impossible, for extremely difficult, if not impossible, for analogue signal processing to achieve analogue signal processing to achieve similar performance.similar performance.

Examples:Examples: FIR filter with linear phase.FIR filter with linear phase. Adaptive filters.Adaptive filters.


Chapter 1, Slide 4


Analogue signal processing is achieved Analogue signal processing is achieved by using analogue components such as:by using analogue components such as: Resistors.Resistors. Capacitors.Capacitors. Inductors.Inductors.

The inherent tolerances associated with The inherent tolerances associated with these components, temperature, voltage these components, temperature, voltage changes and mechanical vibrations can changes and mechanical vibrations can dramatically affect the effectiveness of dramatically affect the effectiveness of the analogue circuitry.the analogue circuitry.


Chapter 1, Slide 5


With DSP it is easy to:With DSP it is easy to: Change applications.Change applications. Correct applications.Correct applications. Update applications.Update applications.

Additionally DSP reduces:Additionally DSP reduces: Noise susceptibility.Noise susceptibility. Chip count.Chip count. Development time.Development time. Cost.Cost. Power consumption.Power consumption.


Chapter 1, Slide 6

Why NOT go digital?Why NOT go digital?

High frequency signals cannot be High frequency signals cannot be processed digitally because of two processed digitally because of two reasons:reasons: AAnalog to nalog to DDigital igital CConverters, onverters, ADCADC cannot cannot

work fast enough.work fast enough. The application can be too complex to be The application can be too complex to be

performed in performed in real-time.


Chapter 1, Slide 7

DSP processors have to perform tasks DSP processors have to perform tasks in real-time, so how do we define real-in real-time, so how do we define real-time?time?

The definition of real-time depends on The definition of real-time depends on the application.the application.

Example: a 100-tap FIR filter is Example: a 100-tap FIR filter is performed in real-time if the DSP can performed in real-time if the DSP can perform and complete the following perform and complete the following operation between two samples:operation between two samples:

Real-time processingReal-time processing

99

0k

knxkany


Chapter 1, Slide 8

We can say that we have a real-time We can say that we have a real-time application if:application if: Waiting Time Waiting Time 0 0

Real-time processingReal-time processing

Processing TimeProcessing TimeWaiting Waiting

TimeTime

Sample TimeSample Timenn n+1n+1


Chapter 1, Slide 9

Why not use a General Purpose Why not use a General Purpose Processor (GPP) such as a Pentium Processor (GPP) such as a Pentium instead of a DSP processor?instead of a DSP processor? What is the What is the power consumptionpower consumption of a of a

Pentium and a DSP processor?Pentium and a DSP processor? What is the What is the costcost of a Pentium and a DSP of a Pentium and a DSP

processor?processor?

Why do we need DSP processors?Why do we need DSP processors?


Chapter 1, Slide 10

Use a DSP processor when the following are Use a DSP processor when the following are required:required: Cost saving.Cost saving. Smaller size.Smaller size. Low power consumption.Low power consumption. Processing of many “high” frequency signals in Processing of many “high” frequency signals in

real-time.real-time. Use a GPP processor when the following are Use a GPP processor when the following are

required:required: Large memory.Large memory. Advanced operating systems.Advanced operating systems.

Why do we need DSP processors?Why do we need DSP processors?


Chapter 1, Slide 11

What are the typical DSP algorithms?What are the typical DSP algorithms?

Algorithm Equation

Finite Impulse Response Filter

M

kk knxany

0

)()(

Infinite Impulse Response Filter

N

kk

M

kk knybknxany

10

)()()(

Convolution

N

k

knhkxny0

)()()(

Discrete Fourier Transform

1

0

])/2(exp[)()(N

n

nkNjnxkX

Discrete Cosine Transform

1

0

122

cos).().(N

x

xuN

xfucuF

The Sum of Products (SOP) is the key The Sum of Products (SOP) is the key element in most DSP algorithms:element in most DSP algorithms:


Chapter 1, Slide 12

Hardware vs. Microcode multiplicationHardware vs. Microcode multiplication

DSP processors are optimised to perform DSP processors are optimised to perform multiplication and addition operations.multiplication and addition operations.

Multiplication and addition are done in Multiplication and addition are done in hardware and in one cycle.hardware and in one cycle.

Example: 4-bit multiply (unsigned).Example: 4-bit multiply (unsigned).

10111011x 1110x 1110

10111011x 1110x 1110

HardwareHardware MicrocodeMicrocode

1001101010011010 000000001011.1011.1011..1011..1011...1011...

1001101010011010

Cycle 1Cycle 1Cycle 2Cycle 2Cycle 3Cycle 3Cycle 4Cycle 4

Cycle 5Cycle 5


Chapter 1, Slide 13

Parameters to consider when choosing a DSP Parameters to consider when choosing a DSP processorprocessor

Parameter

Arithmetic format

Extended floating point

Extended Arithmetic

Performance (peak)

Number of hardware multipliers

Number of registers

Internal L1 program memory cache

Internal L1 data memory cache

Internal L2 cache

32-bit

N/A

40-bit

1200MIPS

2 (16 x 16-bit) with 32-bit result

32

32K

32K

512K

32-bit

64-bit

40-bit

1200MFLOPS

2 (32 x 32-bit) with 32 or 64-bit result

32

32K

32K

512K

TMS320C6211 (@150MHz)

TMS320C6711 (@150MHz)

C6711 Datasheet: C6711 Datasheet: \Links\TMS320C6711.pdf C6211 Datasheet: C6211 Datasheet: \Links\TMS320C6211.pdf


Chapter 1, Slide 14

Parameters to consider when choosing a DSP Parameters to consider when choosing a DSP processorprocessor

Parameter

I/O bandwidth: Serial Ports (number/speed)

DMA channels

Multiprocessor support

Supply voltage

Power management

On-chip timers (number/width)

Cost

Package

External memory interface controller

JTAG

2 x 75Mbps

16

Not inherent

3.3V I/O, 1.8V Core

Yes

2 x 32-bit

US$ 21.54

256 Pin BGA

Yes

Yes

2 x 75Mbps

16

Not inherent

3.3V I/O, 1.8V Core

Yes

2 x 32-bit

US$ 21.54

256 Pin BGA

Yes

Yes

TMS320C6211 (@150MHz)

TMS320C6711 (@150MHz)


Chapter 1, Slide 15

Floating vs. Fixed point processorsFloating vs. Fixed point processors

Applications which require:Applications which require: High precision.High precision. Wide dynamic range.Wide dynamic range. High signal-to-noise ratio.High signal-to-noise ratio. Ease of use.Ease of use.

Need a floating point processor.Need a floating point processor. Drawback of floating point processors:Drawback of floating point processors:

Higher power consumption.Higher power consumption. Can be more expensive.Can be more expensive. Can be slower than fixed-point counterparts and larger in size.Can be slower than fixed-point counterparts and larger in size.


Chapter 1, Slide 16

Floating vs. Fixed point processorsFloating vs. Fixed point processors

It is the application that dictates which It is the application that dictates which device and platform to use in order to device and platform to use in order to achieve optimum performance at a low cost.achieve optimum performance at a low cost.

For educational purposes, use the floating-For educational purposes, use the floating-point device (C6711) as it can support both point device (C6711) as it can support both fixed and floating point operations.fixed and floating point operations.


Chapter 1, Slide 17

General Purpose DSP vs. DSP in ASICGeneral Purpose DSP vs. DSP in ASIC

Application Specific Integrated Circuits Application Specific Integrated Circuits (ASICs) are semiconductors designed (ASICs) are semiconductors designed for dedicated functions.for dedicated functions.

The advantages and disadvantages of The advantages and disadvantages of using ASICs are listed below:using ASICs are listed below:

AdvantagesAdvantages

• High throughputHigh throughput• Lower silicon areaLower silicon area• Lower power consumptionLower power consumption• Improved reliabilityImproved reliability• Reduction in system noiseReduction in system noise• Low overall system costLow overall system cost

DisadvantagesDisadvantages

• High investment costHigh investment cost• Less flexibilityLess flexibility• Long time from design to Long time from design to

marketmarket


Chapter 1, Slide 18

Texas Instruments’ TMS320 familyTexas Instruments’ TMS320 family

Different families and sub-families exist Different families and sub-families exist to support different markets.to support different markets.

Lowest CostLowest CostControl SystemsControl Systems Motor ControlMotor Control StorageStorage Digital Ctrl SystemsDigital Ctrl Systems

C2000C2000 C5000C5000

EfficiencyEfficiency Best MIPS perBest MIPS perWatt / Dollar / SizeWatt / Dollar / Size Wireless phonesWireless phones Internet audio playersInternet audio players Digital still cameras Digital still cameras ModemsModems TelephonyTelephony VoIPVoIP

C6000C6000

Multi Channel and Multi Channel and Multi Function App'sMulti Function App's

Comm InfrastructureComm Infrastructure Wireless Base-stationsWireless Base-stations DSLDSL ImagingImaging Multi-media ServersMulti-media Servers VideoVideo

PerformancePerformance & &Best Best Ease-of-UseEase-of-Use


Chapter 1, Slide 19

TMS320C64x: The C64x fixed-point DSPs offer the industry's highest level of performance to address the demands of the digital age. At clock rates of up to 1 GHz, C64x DSPs can process information at rates up to 8000 MIPS with costs as low as $19.95. In addition to a high clock rate, C64x DSPs can do

more work each cycle with built-in extensions. These extensions include new instructions to accelerate performance in key application areas such as digital communications infrastructure and video and image processing.

TMS320C62x: These first-generation fixed-point DSPs represent breakthrough technology that enables new equipments and energizes

existing implementations for multi-channel, multi-function applications, such as wireless base stations, remote access servers (RAS), digital subscriber

loop (xDSL) systems, personalized home security systems, advanced imaging/biometrics, industrial scanners, precision instrumentation and multi-

channel telephony systems.

TMS320C67x: For designers of high-precision applications, C67x floating-point DSPs offer the speed, precision, power savings and dynamic range to

meet a wide variety of design needs. These dynamic DSPs are the ideal solution for demanding applications like audio, medical imaging,

instrumentation and automotive.


Chapter 1, Slide 20

C6000 RoadmapC6000 RoadmapP

erf

orm

an

ce

Time

C62x/C64x/DM642: Fixed PointC67x: Floating PointC62x/C64x/DM642: Fixed PointC67x: Floating Point

Highest

Perform

ance

Object Code Software CompatibilityFloating PointFloating Point

Multi-coreMulti-core C64x™ DSP 1.1 GHz

C64x™ DSP 1.1 GHz

C6201

C6701

C6202C6203

C6211C6711

C6204

1st Generation

C6713C6713

C6205

C6712

C6412C6412 DM642DM642

2nd Generation

C6415C6415

C6416C6416

C6411C6411

C6414C6414


Chapter 1, Slide 21

Useful LinksUseful Links

Selection Guide: Selection Guide: \Links\DSP Selection \Links\DSP Selection Guide.pdfGuide.pdf

\Links\DSP Selection Guide.pdf (3Q 2004)\Links\DSP Selection Guide.pdf (3Q 2004)

\Links\DSP Selection Guide.pdf (4Q 2004)\Links\DSP Selection Guide.pdf (4Q 2004)

Chapter 1Chapter 1

IntroductionIntroduction

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