dsp casestudy

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Introduction:

Digital signal is one of the core technologies, in rapidly

growing applications areas, such as wireless communications, audio and video

processing and industrial control dramatically over the last few years . DSP has

become a key component, in many of the products that include some form of

digital signal processing using microprocessors. DSP’s are processors or micro-

processors whose hardware, software and instruction sets are optimized for

high-speed numeric processing applications, an essential for processing digital

data, representing analog signals in real time. The DSP processors have gained

increased popularity because of various advantages like reprogram ability in the

field, speed, energy efficiency etc.

DSP techniques have been very successful because of the development of

low-Cost software and hardware support.for example, modems and speech

recognition can be less expensive using DSP techniques. DSP processors such as

the TMS320C6X family of processors are like fast special-purpose micropro-

cessors with a specialized type of architecture and an instruction set appropriate

for signal processing.

The TMS320C6X are the first processors to use velocity architecturehaving implemented the Very Long Instruction Word(VLIW). This new

architecture supports features that facilitate the development of efficient

high level language compiler. The TMS320C6713 is a low-cost standalone

development platform that enables users to evaluate and develop applications

for the TI C67xx DSP family. The DSK also serves as a hardware reference

design for the TMS320C6713 DSP. Schematics, logic equations and application

notes are available to ease hardware development and reduce time to market.



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Difference between DSP processors and othermicroprocessor

DSP processors are designed for application such as image processing,

speech recognition & telecommunication.

DSP processors are more efficient.

DSP processors are faster in calculation.

DSP’s perform parallel operation.

DSP’s are very costly.

DSP’s are found in devices such ascell phones,DVD players and Digital

cameras.

Microprocessors are designed to run software applications such as word

processors, spreadsheet and Web browsers.

Microprocessors are less efficient.

Microprocessors are slower in calculation. Microprocessors perform serial operation.

Microprocessors are cheaper.

Microprocessors are the core of desktop, Laptop , netbooks, tablet pc’s.



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Important features of DSP processors

As the DSP processors are designed and optimized for implementations of

various DSP algorithms, most processors share common features to support the

high Performance, repetitive numeric intensive tasks.

1) MACs and Multiple Execution Units The most commonly known and used feature of a DSP processor is the

ability toPerform one o multily-accumulate operation(also known as”MACs”) in

a single instruction cycle.The MAC operation is useful in DSP algorithms that

involve com-putting a vector dot product, such as digital filters,correlation, andfourier transform.

2) Efficient Memory AccessDSP processor also share a feature of efficient memory access i.e the ability

to complete several access to memory in a single instruction cycle. Due to

Hardware architecture in DSP processor , i.e physically separate storage and



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signal pathways for instructions and data, the processor is able to fetch an

instruction while simulta- neously fetching operants and/or storing the result of

previous instruction to memory.

3) Circular BufferingThe need of processing the digital signal in real time, where the output have

to be produced at the same time at which the input samples are being acquired,

evolves the concept of circular buffering. Circular buffering allows to processors

to access a block of data sequentially and then automatically wrap around to the

beginning address .for instance circular buffering is needed in telephone

communication,hearing aids etc.

4) Dedicated Address Generation UnitThe dedicated address generation unit help to speed up the performance of

the arithmetic processing on DSP. Once an appropriate addressing registers have

been configured, the address generation unit operates in background. DSP

processor address generation unit typically support a slection of addressing

modes tailored to DSP applications.

5) Specialized Instruction SetsThe instruction sets of the DSP processors are designed to make maximum

use of the processors resources and at the same time minimize the memory space

required to store the instructions.



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Typical Applications

Telecommunications : Telephone lines modem , FAX, Cellular

telephones, Wireless Networks, Speaker Phones.

Voice/Speech : Speech Digitization and Compression, Voice mail,

Speaker verifyication and Speech synthesis.

Automotive : Engine control, Antilock brakes, Active suspension,

System diagnosis.

Control systems : Laser printer control, Robot control, Engine and Motor

control, Numeric control of automatic machine tools.

Military : Radar and Sonar signal processing, Navigation systems missile

guidance , HF radio frequency modems, Secure spread spectrum radio’s

and Secure voice.

Medical : Hearing aid, MRI imaging, Ultrasound imaging.

Instrumentation : Spectrum analysis, Transient analysis, Signal

generators.

Image Processing : Image enhancement, Image compression and

Transmission, 3-d rotation and Animation.



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TMS320C6713 DSK SUPPORT TOOLS

1) TI’s DSP starter kit (DSK).The DSK package includes:

(a) Code Composer Studio (CCS), which provides the necessary software

support tools. CCS provides an integrated development environment

(IDE), bringing together the C compiler, assembler, linker, debugger, and

so on.

(b) A board, shown in Figure 1.1, that contains the TMS320C6713 (C6713)

floating-point digital signal processor as well as a 32-bit stereo codec for

input and output (I/O) support.

(c) A universal synchronous bus (USB) cable that connects the DSK board

to a PC.

(d) A 5V power supply for the DSK board.

2) An IBM-compatible PC.The DSK board connects to the USB port of the PC

through the USB cable included with the DSK package.

3) An oscilloscope, signal generator, and speakers.A signal/spectrum analyzer is

optional.Shareware utilities are available that utilize the PC and a sound card

to create a virtual instrument such as an oscilloscope, a function generator, or

a spectrum analyzer.



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Diagram of TMS320C6713 DSK

FIG: Block Diagram of TMS320C6713 DSK

Features of TMS320C6713 DSKThe DSK comes with a compliment of on-board devices that suit a

Variety of application enviroments.key features include

A Texas Instruments TMS320C6713 DSP operating at 225 MHz.

16 Mbytes of synchronous DRAM.

512 Kbytes of non-volatile Flash Memory.

4 user accessible LED’s and DIP switches.

Configurable boot options.

Interface or external emulator

Single voltage power supply(+5v).



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Functional Overview of the TMS320C6713 DSK

The DSP on the 6713 DSK interfaces to on-board peripherals

through a 32-bit wide EMIF (External Memory InterFace). The SDRAM,

Flash and CPLD are all connected to the bus. EMIF signals are also

connected daughter card expansion connectors which are used for third

party add-in boards. The DSP interfaces to analog audio signals through an

on-board AIC23 codec and four 3.5 mm audio jacks (microphone input, line

input, line output, and headphone output).

The codec can select the microphone or the line input as the

active input. The analog output is driven to both the line out (fixed gain) and

head-phone (adjustable gain) connectors. McBSP0 is used to send commandsto the codec control interface while McBSP1 is used for digital audio data.

McBSP0 and McBSP1 can be re-routed to the expansion connectors in

software. A program-mable logic device called a CPLD is used to implement

glue logic that ties the board components together. The CPLD has a register

based user interface that lets the user configure the board by reading and

writing to its registers.

The DSK includes 4 LEDs and a 4 position DIP switch as a simpleway to provide the user with interactive feedback. Both are accessed by

reading and writing to the CPLD registers. An included 5V external power

supply is used to power the board. On-board switching voltage regulators

provide the +1.26V DSP core voltage and +3.3V I/O supplies. The board is

held in reset until these supplies are within operating specifications. Code

Composer communicates with the DSK through an embedded JTAG emulator

with a USB host interface. The DSK can also be used with an external

emulator through the external JTAG connector.



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Major board components on the TMS320C6713 DSK.

1) CPLD (Programmable Logic)

The C6713 DSK uses an Altera EPM3128TC100-10 Complex Programmable

Logic Device (CPLD) device to implement:

• 4 Memory-mapped control/status registers that allow software

control of various board features.

• Control of the daughter card interface and signals.

• Assorted "glue" logic that ties the board components together.

2) AIC23 Codec

The DSK uses a Texas Instruments AIC23 (part #TLV320AIC23) stereo codec

for input and output of audio signals. The codec samples analog signals on the

microphone orline inputs and converts them into digital data so it can be

processed by the DSP. When the DSP is finished with the data it uses the codec

to convert the samples back into analog signals on the line and headphone

outputs so the user can hear the output.



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3) Synchronous DRAMThe DSK uses a 128 megabit synchronous DRAM (SDRAM) on the 32-bit

EMIF. The SDRAM is mapped at the beginning of CE0 (address 0x80000000).

Total available memory is 16 megabytes. The integrated SDRAM controller is

part of the EMIF and must be configured in software for proper operation. TheEMIF clock is derived from the PLL settings and should be configured in

software at 90MHz. This number is based on an internal PLL clock of 450 MHz

required to achieve 22.

4) Flash MemoryFlash is a type of memory which does not lose its contents when the

power is turned off. When read it looks like a simple asynchronous read-only

memory (ROM). Flash can be erased in large blocks commonly referred to assectors or pages. Once a block has been erased each word can be programmed

once through a specialcommand sequence. After than the entire block must be

erased again to change the contents. The DSK uses a 512Kbyte external Flash as a

boot option.

5) LEDs and DIP SwitchesThe DSK includes 4 software accessible LEDs (D7-D10) and DIP switches

(SW1) that provide the user a simple form of input/output. Both are accessed

through the CPLD USER_REG register.

6) Daughter Card InterfaceThe DSK provides three expansion connectors that can be used to accept

plug-in daughter cards. The daughter card allows users to build on their DSK

platform to extend its capabilities and provide customer and application specific

I/O. The expansion connectors are for memory, peripherals, and the Host Port

Interface (HPI).The memory connector provides access to the DSP’s asynch-

ronous EMIF signals to interface with memories and memory mapped devices. It

supports byte addressing on 32 bit boundries. The peripheral connector brings

out the DSP’s peripheral signals like McBSPs, timers, and clocks. Both conn-

ectors provide power and ground to the daughter card.



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Memory Mapping in TMS320C6713 DSK

The C67xx family of DSPs has a large byte addressable address space. Program

code and data can be placed anywhere in the unified address space. Addresses

are always 32-bits wide.The memory map shows the address space of a generic

6713 processor on the left with specific details of how each region is used on the

right. By default, the internal memory sits at the beginning of the address space.

Portions of the internal memory can be reconfigured in software as L2 cache

rather than fixed RAM.

The EMIF has 4 separate addressable regions called chip enable spaces

(CE0-CE3). The SDRAM occupies CE0 while the Flash and CPLD share CE1.

CE2 and CE3 are generally reserved for daughtercards.



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Programming with TMS320C6713

Steps involved in programming is as follows:

i) Connecting the C6713 DSK



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ii) Programming

1] Create a folder called “myprojects” on the desktop.

Fig : Code composer Studio

2] Run the C6713 DSK Code composer Studio(C6713 DSK CCS).

3] Go to the Project : New, create a new project dtmf.

4] Make sure the Project type is Executable(.out) and target is TMS329C67XX.

5] Download the dtmf.cdb file from http://www.ece.mtu.edu/labs/EElabs/EE3306/resources.

6] Once the project is created , go to project, Add files to project , add the DSK

C6713 Board Support Library(BSL) file. This library will simplify the



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Communication with the board using c language. More information about this

library can be found in Help TMS320C6713 DSK Software Board support

Library.

7] Next include the “dtmf.cdb” file form the web page.

8] Finally you can create a new file and begin the laboratory assignment.

Remember to save the file as ” dtmf.c” and include it to the project in order for

it to run

iii) Compiling into machine language1) After writing the code ,the next step is to compile the code to manchine

language.

Go to project Build

2)The build command will compile all the files that are include in this

Project and make an executable file for the dsp.

3)Compiler results are shown at the bottm of the window.



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iv) Loading program into DSP processor 1) Finally to run the program, load the program into dsp.

Go to File Load program Load the executable file.

Fig : Load program



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2) Run the file loaded into the dsp.

Go to debug Run

Fig : Program running

3) Output is displayed.



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Physical layout of the TMS320C6713 DSK and itsconnectors.

1) Board LayoutThe C6713 DSK is a 8.75 x 4.5 inch (210 x 115 mm.) multi-layer board which

is powered by an external +5 volt only power supply. Figure shows the layout

of the C6713 DSK.

2) Connector IndexThe TMS320C6713 DSK has many connectors which provide the user access

to the various signals on the DSK



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3) Expansion ConnectorsThe TMS320C6713 DSK supports three expansion connectors that follow the

Texas Instruments interconnection guidelines. The expansion connector pinouts

are described in the following three sections.

I is on an Input pin

is on an Output pin Z is on a High Impedance pin

4) Audio ConnectorsThe C6713 DSK has 4 audio connectors. They are described in the following

sections.

a) J301, Microphone Connector

The input is a 3.5 mm. stereo jack. Both inputs are connected to themicrophone so it is monaural. The signals on the plug are shown in the figure

below.



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b) J303, Audio Line In ConnectorThe audio line in is a stereo input. The input connector is a 3.5 mm stereo

jack.The signals on the mating plug are shown in the figure below.

c) J304, Audio Line Out ConnectorThe audio line out is a stereo output. The output connector is a 3.5 mm

stereo Jack. The signals on the mating plug are shown in the figure below.

d) J303, Headphone Connector

Connector J4 is a headphone/speaker jack. It can drive standardheadphones or a High impedance speaker directly. The standard 3.5 mm jack

is shown in the Figure below.



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5) Power ConnectorsThe C6713 DSK has 2 power connectors. They are described in the

following sections.

a) J5, +5 Volt ConnectorPower (+5 volts) is brought onto the TMS320C6713 DSK via the J5

connector.The connector has an outside diameter of 5.5 mm. and an inside

diameter of 2.5 mm. A diagram of J5 is shown below.

b) J6, Optional Power ConnectorConnector J6 is an optional power connector. It will operate with the

standard personal computer power supply. The table below shows the

voltages on the respective pins.



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Support filesFollowing are the support files.

1) C6713dskinit.c :Contains function to initialize the DSK, the Codec, the

serial ports, and for I/O. It is not included with CCS.

2) C6713dskinit.h : Header file with function prototypes.Features such as

those used to select the mic input in lieu of line input (by default), input

gain, and soon are obtained from this header file (modified from a similar

file included with CCS).

3) C6713dsk.cmd: sample linker command file. This generic file can be

changed when using external memory in lieu of internal memory.

4) Vectors_intr.asm: a modified version of a vector file included with CCS

to handle interrupts. Twelve interrupts, INT4 through INT15,are available,

and INT11 is selected within this vector file.They are used for interrupt-

driven programs

5) Vectors_poll.asm: vector file for programs using polling.

6) rts6700.lib,dsk6713bsl.lib,csl6713.lib: run-time, board, and chipsupport library files, respectively. These files are included with CCS and are

located in C6000\cgtools\lib, C6000\dsk6713\lib, and c6000\bios\lib,

respectively.



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Conclusion:

There are many applications for which the Digital Signal Processor

becomes an ideal choice as they provide the best possible combination of

performance, power and cost. Most of the DSP applications can be simplified

into multipli -cations and additions, so the MAC formed a main functional

unit in early DSP processors. The designers later incorporated more features,

like pipelining, SIMD, VLIW etc, in the processors to deliver improved

performance.

There has been a drive to develop new benchmarking schemes as the

improvement in the processor architecture made the earlier benchmarking

schemes, obsolete and less reliable.Power issues are gaining importance as

DSP processors are incorporated in to handheld, mobile and portable devices.This leads to development of an important class of DSP processors namely

fixed-point processors. Based on the current trends seen in the DSP processor

development we may predict that the manufacturers will follow the path of

general purpose processors. With new IC manufacturing technologies

available we may expect to see more on-chip peripherals and memory; and in

fact the system on chip may not be too far away.



References:

Digital signal Processing & Applications with C6713 and C6413 DSK

- By Rulph Chassaing.

DSP Application using TMS320C6X DSK

-By Suvad Selman.

The Scientists & Engineering Guide to Dsp

- By Steven .W. Smith

WWW.Wikipedia .Com

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