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DSP Development System
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• Installing and testing Code Composer Studio Version 3.1
• Use of the TMS320C6713
• Programming examples
This chapter describes how to install and test Texas Instruments ’ integrated development environment (IDE), Code Composer Studio (CCS), for either the TMS320C6713 Digital Signal Processing Starter Kit (DSK). Three example programs that demonstrate hardware and software features of the DSK and CCS are presented. It is recommended strongly that you review these examples before proceeding to subsequent chapters. The detailed instructions contained in this chapter are specific to CCS Version 3.1.
1.1 INTRODUCTION
The Texas Instruments TMS320C6713 Digital Signal Processing Starter Kits are low cost development platforms for real - time digital signal processing applications. Each comprises a small circuit board containing either a TMS320C6713 floating - point digital signal processor and a TLV320AIC23 analog interface circuit (codec) and connects to a host PC via a USB port. PC software in the form of Code Composer Studio (CCS) is provided in order to enable software written in C or assembly language to be compiled and/or assembled, linked, and downloaded to run on the DSK. Details of the TMS320C6713, TLV320AIC23, DSK, and CCS can be found in their associated datasheets [36 – 38] . The purpose of this chapter is to introduce the installation and use of either DSK.
A digital signal processor (DSP) is a specialized form of microprocessor. The architecture and instruction set of a DSP are optimized for real - time digital signal processing. Typical optimizations include hardware multiply - accumulate (MAC) provision, hardware circular and bit - reversed addressing capabilities (for efficient implementation of data buffers and fast Fourier transform computation), and Harvard architecture (independent program and data memory systems). In many cases, DSPs resemble microcontrollers insofar as they provide single chip computer solutions incorporating onboard volatile and nonvolatile memory and a range of
peripheral interfaces and have a small footprint, making them ideal for embedded applications. In addition, DSPs tend to have low power consumption requirements. This attribute has been extremely important in establishing the use of DSPs in cellular handsets. As may be apparent from the foregoing, the distinctions between DSPs and other, more general purpose, microprocessors are blurred. No strict definition of a DSP exists. Semiconductor manufacturers bestow the name DSP on products exhibiting some, but not necessarily all, of the above characteristics as they see fit.
The C6x notation is used to designate a member of the Texas Instruments (TI)
TMS320C6000 family of digital signal processors. The architecture of the C6x digital
signal processor is very well suited to numerically intensive calculations. Based on a very - long - instruction - word (VLIW) architecture, the C6x is considered to be TI ’ s most powerful processor family.
Digital signal processors are used for a wide range of applications, from communications and control to speech and image processing. They are found in cellular phones, fax/modems, disk drives, radios, printers, hearing aids, MP3 players, HDTV, digital cameras, and so on. Specialized (particularly in terms of their onboard peripherals) DSPs are used in electric motor drives and a range of associated automotive and industrial applications. Overall, DSPs are concerned primarily with real - time signal processing. Real - time processing means that the processing must keep pace with some external event; whereas non real - time processing has no such timing constraint. The external event to keep pace with is usually the analog input. While analog - based systems with discrete electronic components including resistors and capacitors are sensitive to temperature changes, DSP - based systems are less affected by environmental conditions such as temperature. DSPs enjoy the major advantages of microprocessors. They are easy to use, flexible, and economical.
A number of books and articles have been published that address the importance of digital signal processors for a number of applications [1 – 22] . Various technologies have been used for real - time processing, from fiber optics for very high frequency applications to DSPs suitable for the audio frequency range. Common applications using these processors have been for frequencies from 0 to 96 kHz. It is standard within telecommunications systems to sample speech at 8 kHz (one sample every 0.125 ms). Audio systems commonly use sample rates of 44.1 kHz (compact disk) or 48 kHz. Analog/digital (A/D) - based data - logging boards in the megahertz sampling
rate range are currently available.
1.2 DSK SUPPORT TOOLS
Most of the work presented in this book involves the development and testing of short programs to demonstrate DSP concepts. To perform the experiments described in the book, the following tools are used:
1. A Texas Instruments 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 circuit board (the TMS320C6713 DSK is shown in Figure 1.1 ) containing a digital signal processor and a 16 - bit stereo codec for analog signal input and output.
© A universal synchronous bus (USB) cable that connects the DSK board to a PC.
(d) A +5 V universal power supply for the DSK board.
2. A PC . The DSK board connects to the USB port of the PC through the USB
cable included with the DSK package.
3. An oscilloscope, spectrum analyzer, signal generator, headphones, microphone, and speakers . The experiments presented in subsequent chapters of this book are intended to demonstrate digital signal processing concepts in real - time, using audio frequency analog input and output signals. In order to appreciate those concepts and to get the greatest benefit from the experiments, some forms of signal source and sink are required. As a bare minimum, a microphone and either headphones or speakers are required. A far greater benefit will be
acquired if a signal generator is used to generate sinusoidal, and other, test signals and an oscilloscope and spectrum analyzer are used to display, measure, and analyze input and output signals. Many modern digital oscilloscopes incorporate FFT functions, allowing the frequency content of signals to be displayed. Alternatively, a number of software packages that use a PC equipped with a soundcard to implement virtual instruments are available.
All the files and programs listed and discussed in this book (apart from some of the student project files in Chapter 10 ) are included on the accompanying CD.
1.2.1 C 6713 DSK Boards
The DSK packages are powerful, yet relatively inexpensive, with the necessary hardware and software support tools for real - time signal processing [23 – 43] . They are complete DSP systems. The DSK boards, which measure approximately 5 8 inches, include either a 225 - MHz C6713 floating - point digital signal processor or a 1 - GHz C6416 fixed - point digital signal processor and a 16 - bit stereo codec TLV320AIC23 (AIC23) for analog input and output.
The onboard codec AIC23 [38] uses sigma – delta technology that provides analog - to - digital conversion (ADC) and digital - to - analog conversion (DAC) functions. It uses a 12 - MHz system clock and its sampling rate can be selected from a range of alternative settings from 8 to 96 kHz. A daughter card expansion facility is also provided on the DSK boards.
Two 80 - pin connectors provide for external peripheral and external memory interfaces.
The DSK boards each include 16 MB (megabytes) of synchronous dynamic RAM (SDRAM) and 512 kB (kilobytes) of flash memory. Four connectors on the boards provide analog input and output: MIC IN for microphone input, LINE IN for line input, LINE OUT for line output, and HEADPHONE for a headphone output (multiplexed with line output). The status of four user DIP switches on the DSK board can be read from within a program running on the DSP and provide the user with a feedback control interface. The states of four LEDs on the DSK board can be controlled from within a program running on the DSP. Also onboard the DSKs are voltage regulators that provide 1.26 V for the DSP cores and 3.3 V for their memory and peripherals.