This chapter provides a series of applications.

1

• Chapter 20
• This chapter provides a series of applications.
• Part 1 Applications using the PCM3003 AUDIO
  DAUGHTER CARD TMDX326040A)
• by Richard Sikora
• Part 2 USB Daughter Board.
• by ATE Communications
• Part 3 PCI C6711 DSP Educational Board.
• by ATE Communications

2
Introduction

• Some audio applications for the TMS320C6711 DSK
  with Audio Daughter Card have been provided.
• These include
• Alien Voices Changing voices using ring
  modulation. Widely used in science- fiction films
  for alien voices.
• Delays and Echo Using buffers to delay a signal
  up to 4 seconds to simulate echo from a valley /
  cavern.
• Electronic Crossover Dividing audio signal into
  bass and treble using Finite Impulse Response
  (FIR) filters.

3
Introduction

• These include
• Guitar Effects Changing sound of an electric
  guitar by adding reverberation, treble boost and
  distortion.
• Guitar Tuner Tuning the strings of an electric
  guitar using an adaptive filter. Display of
  accuracy of tuning on LEDs.
• Playback and Record Using buffers to record and
  playback sounds. Half speed and double speed
  playback. Introduces concepts of decimation and
  interpolation.
• Reverberation Simulation of reflections from
  walls to make a small room sound like an
  auditorium.

4
Introduction

• These include
• Signal Generator Generating test waveforms
  sine and triangle, continuous, burst and sweep
  between 60 Hz and 12 kHz.

5
Code Location

• The CCS projects are in the following location
• \Code\Chapter 20 Other Applications\Audio
  Daugtercard
• See the following for more information
• \Links\Using the Applications.pdf

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Chapter 20, Part 2 USB Daughter Board by ATE
Communications (www.ate.co.uk)
7
Overview

• Combined signal acquisition/generation and USB
  interface card
• Data acquisition/generation via 1 audio CODEC, 2
  ADCs and 2 DACs. (See Chapter 8 for
  applications).
• PC interface to DSK via USB chipset.
• USB chipset to DSP on DSK via EMIF.

8
Audio CODEC CS4218(see Chapter 8)

• High quality stereo audio input and output.
• Sampling rate of 48 kHz.
• 16 bit output (same resolution as audio CD).
• Interface to DSP via serial ports.

9
ADCs and DACs AD9220 and AD768

• Two ADCs for digital to analogue conversion of
  high frequency signals.
• Two DACs for arbitrary waveform generation of
  high frequency signals.
• Interface between DSP and converters via DSP's
  EMIF.

10
USB Interface Chipset

• USB revision 1.1 full speed device.
• 16 bit interface to DSP via EMIF.
• Data transfer rates between DSP and PC of up to
  7M bits per second.
• Internal FIFOs with programmable empty and full
  flags connected to DSP's timer input pins.

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Using the Audio CODEC (1)

• Set up transmit and receive serial ports' pins.
  Serial ports should be set up to use external
  frame synch and clock signals.
• Rising edges are used to clock transmit/receive
  data and frame synchs are active high.

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Using the Audio CODEC (2)

• Set up the serial ports to use 32 bit words, the
  data are delayed by one clock edge, no companding
  is used.
• The sample data are in the upper 16 bit words of
  each 32 bit word. The lower 16 bits are used for
  control information.

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Using the DACs and ADCs (1)

• The DACs and ADCs are connected to the DSP's
  EMIF.
• DACs and ADCs can be accessed by reading from and
  writing to the DSP's CE3 memory space.

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Using the DACs and ADCs (2)

• A 32 bit read from the CE3 memory space reads
  packed data, two 16 bit words per 32 bit word.
  The ADCs have 12 bit resolution and should be
  converted to 2's complement signed values.
• A 32 bit write to the CE3 memory space writes
  data to both DACs. The data are packed, two 16
  bit words per 32 bit word. The DACs have 16 bit
  resolution.

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Using the USB interface (1)

• Using the USB interface from the PC requires
  software to communicate with the device driver.
• The USB chipset is connected to the DSP via the
  EMIF.
• The USB chip is mapped to the DSP's CE2 memory
  space.
• The CE2 memory space should be set up using the
  following value for the CE2 control register
  0x7136C424.

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Using the USB interface (2)

• Reading and writing to USB accomplished by
  accessing CE2 memory space.
• FIFO flags connected to DSPs timer inputs
  provide information on USB chips FIFO status.
• DSP should monitor FIFO flags to avoid under or
  overruns.

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PC - USB daughter board communication

• Communicating with the board from the PC requires
  code to interface to the USB device driver.
• Lower level details of communicating with the
  device are handled by the device driver.
• Code running on a built-in micro controller on
  the USB chip is used to move the data between the
  USB buffers and external port FIFOs.

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PC - USB daughter board communication
Application FFT processed on the DSK, results
sent to the PC via the USB interface and the
spectrum is display on the PC. Files
location \Chapters\Usb
19
Chapter 20, Part 3 PCI C6711 DSP Educational
Board, PCIC67AT by ATE Communications
(www.ate.co.uk) Datasheet Block Diagram
20
Overview (1)

• C6711 based PCI card with a variety of signal
  acquisition and generation peripherals.
• Video encoder for acquisition of video data.
• Video decoder for generation of video signals.
• Stereo audio CODECs for acquisition and
  generating audio signals.
• High frequency ADCs and DACS for high frequency
  signal acquisition and generation.

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Overview (2)

• Additional features
• PC has access to DSP via PCI interface.
• JTAG controller for tight integration with CCS.
• Bus matching FIFOs for managing high bandwidth of
  video data on video encoder and decoder.
• Large amount of SDRAM for program and data
  storage.

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Video encoder

• DSP has access to video encoder output data via
  memory mapped FIFO.
• FIFO flag connected to DSP's external interrupt
  to facilitate using EDMA to move data from FIFO
  to other memory locations.
• Video encoder set up using I2C bus.
• Video encoder should write framing codes to FIFO
  to facilitate synchronising to data stream.

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Video decoder

• DSP has access to video decoder input port via
  memory mapped FIFO.
• Video decoder data input format compatible with
  output format of encoder.
• Video encoder internal registers set up via I2C
  bus.

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Audio CODECs CS4218

• Connected to DSP's serial ports.
• Two stereo audio CODECs available providing four
  input and four output channels.
• Audio CODECs use 16 bit data at 48 kHz sampling
  rate.

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ADCs and DACs AD9220, AD768

• High frequency ADCS for capturing of high
  frequency signals
• ADCs memory mapped in DSP for high bandwidth
  parallel interface
• DACs useful for outputting processed waveforms or
  arbitrary waveform generation
• DACs memory mapped in DSP for high bandwidth
  parallel interface

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Programming the DSP

• Use of JTAG emulator connected to JTAG header on
  board.
• Directly in CCS via on board JTAG controller.
• Single step debugging of DSP possible when using
  CCS .
• Access to all internal memory locations of DSP
  via HPI connected to PCI interface.

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Accessing data on DSP from PC

• Using PCI device driver.
• PCI devices are plug and play, set up of devices
  in PC straightforward.
• PCI device connected to DSP's HPI.
• Via DSP's EMIF programmer has access to all
  peripherals connected to EMIF.

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Stand alone operation

• External power connector for stand alone
  operation.
• Programming DSP via JTAG header using JTAG
  interface board such as XDS510.
• Less complex than PCI set up, no operating system
  trouble or need for device drivers.

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Chapter 20 - End -