17-06-2013, 03:57 PM
DSP Applications Using C and the TMS320C6x DSK
DSP Applications.pdf (Size: 4.01 MB / Downloads: 67)
DSP Development System
• Testing the software and hardware tools with Code Composer Studio
• Use of the TMS320C6711 DSK
• Programming examples to test the tools
Chapter 1 introduces several tools available for digital signal processing (DSP).
These tools include the popular Code Composer Studio (CCS), which provides an
integrated development environment (IDE); the DSP starter kit (DSK) with the
TMS320C6711 floating-point processor onboard and complete support for input
and output. Three examples are included to test both the software and hardware
tools included with the DSK.
INTRODUCTION
Digital signal processors such as the TMS320C6x (C6x) family of processors are like
fast special-purpose microprocessors with a specialized type of architecture and
instruction set appropriate for signal processing. The C6x notation is used to designate
a member of Texas Instruments’ (TI) TMS320C6000 family of digital signal
processors. The architecture of the C6x digital signal processor is very well suited
for numerically intensive calculations. Based on a very-long-instruction-word
(VLIW) architecture, the C6x is considered to be TI’s most powerful processor.
Digital signal processors are used for a wide range of applications, from communications
and controls to speech and image processing. They are found in cellular
phones, fax/modems, disk drives, radio, and so on.These processors have become
the product of choice for a number of consumer applications, since they have
become very cost-effective.
DSK Board
The DSK package is powerful, yet relatively inexpensive ($295), with the necessary
hardware and software support tools for real-time signal processing [21–33]. It is a
complete DSP system. The DSK board, with an approximate dimension of 5 ¥ 8
inches, includes the C6711 floating-point digital signal processor [22] and a 16-bit
codec AD535 for input and output.
The onboard codec AD535 [34] uses a sigma–delta technology that provides
analog-to-digital conversion (ADC) and digital-to-analog conversion (DAC). A
4-MHz clock onboard the DSK connects to this codec to provide a fixed sampling
rate of 8kHz.
A daughter card expansion is also provided on the DSK board.We will illustrate
input and output by plugging an audio daughter card based on the PCM3003 stereo
codec (not included with the DSK package) into an 80-pin connector on the DSK
board.The audio daughter card is available from Texas Instruments and is described
in Appendix F.The PCM3003 codec has variable sample rates up to 72 kHz and can
be useful for applications requiring higher sampling rates and two accessible input
and output channels.
The DSK board includes 16MB (megabytes) of synchronous dynamic RAM
(SDRAM) and 128kB (kilobytes) of flash ROM. Two connectors on the board
provide input and output and are labeled IN (J7) and OUT (J6), respectively.Three
of the four user dip switches on the DSK board can be read from a program (a
project example on voice scrambling makes use of these switches). The onboard
clock is 150MHz. Also onboard the DSK are voltage regulators that provide 1.8V
for the C6711 core and 3.3V for its memory and peripherals.
TMS320C6711 Digital Signal Processor
The TMS320C6711 (C6711) is based on the very-long-instruction-word (VLIW)
architecture, which is very well suited for numerically intensive algorithms. The
internal program memory is structured so that a total of eight instructions can be
fetched every cycle. For example, with a clock rate of 150MHz, the C6711 is capable
of fetching eight 32-bit instructions every 1/(150 MHz) or 6.66 ns.
Features of the C6711 include 72 kB of internal memory, eight functional or execution
units composed of six ALUs and two multiplier units, a 32-bit address bus to
address 4 GB (gigabytes), and two sets of 32-bit general-purpose registers.
CODE COMPOSER STUDIO
The Code Composer Studio (CCS) provides an integrated development environment
(IDE) to incorporate the software tools. CCS includes tools for code generation,
such as a C compiler, an assembler, and a linker. It has graphical capabilities
and supports real-time debugging. It provides an easy-to-use software tool to build
and debug programs.
The C compiler compiles a C source program with extension .c to produce an
assembly source file with extension.asm.The assembler assembles an.asm source
file to produce a machine language object file with extension.obj.The linker combines
object files and object libraries as input to produce an executable file with
extension.out. This executable file represents a linked common object file format
(COFF), popular in Unix-based systems and adopted by several makers of digital
signal processors [21]. This executable file can be loaded and run directly on the
C6711 processor.
CCS Installation and Support
Use the parallel (printer) cable DB25 to connect the DSK board (J2) to the parallel
port on the PC, such as LPT1 or LPT2. Use the 5-V adapter included with the
DSK package to connect to the power connector J4, to turn on the DSK. Install
CCS with the CD-ROM included with the DSK, preferably using the c:\ti
structure (as default).
Support Files
Create a new folder within your PC hard drive and name it sine8_intr. It is recommended
that you place this folder in c:\ti\myprojects (it is assumed that
you have installed CCS in c:\ti). Some of the same support files that are used in
many examples in this book are included on the accompanying disk in the folder
Support. For now, don’t worry too much about the content or functions of these
files. Additional support files are included in the CCS CD with the DSK package.