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ECE 477 Design Review Team 9  Spring 2009

ECE 477 Design Review Team 9  Spring 2009. Isaac Jones. Brett Mravec. Greg McCoy. Danielle Miller. Outline. Project overview Project-specific success criteria Block diagram Component selection rationale Packaging design Schematic and theory of operation PCB layout

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ECE 477 Design Review Team 9  Spring 2009

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  1. ECE 477 Design Review Team 9  Spring 2009 Isaac Jones Brett Mravec Greg McCoy Danielle Miller

  2. Outline • Project overview • Project-specific success criteria • Block diagram • Component selection rationale • Packaging design • Schematic and theory of operation • PCB layout • Software design/development status • Project completion timeline • Questions / discussion

  3. Project Overview • Mobile digital audio player • Plays FLAC audio files stored on a removable SecureDigital (SD) card • Synthesizes the sound data to a 3.5mm headphone jack • LCD Display and buttons for user input • Integrated lithium Ion battery and on-board charging circuit

  4. Project-Specific Success Criteria • An ability to decode files stored in the FLAC format • An ability to select files stored on the device • An ability to display visualization information • An ability to output audio to a headphone or speaker port • An ability to pause and resume playback on user input.

  5. Block Diagram

  6. Component Selection Rationale • Considerations for all components • Lightweight • Low power consumption • Small size

  7. Component Selection Rationale Audio DSP Sufficient processing capabilities Easy audio interfacing SPI interface for SD card and other peripherals D/A High performance for audio Easy to interface to DSP, or built-in

  8. Component Selection Rationale

  9. Component Selection Rationale • LCD & Battery two largest components • Both need to be extremely thin • 15 mm allowance for LCD & Li-Ion battery • 8.9 mm LCD + 5.8 mm battery = 14.7 mm • LCD preferably graphics capable (not character-based, but not TV-quality either)

  10. Packaging Design • Off-the-shelf enclosure • Larger than competitors such as the iPod and Sandisk Sanza, but still highly portable • Very tight tolerances for parts fit!

  11. Schematic/Theory of Operation Digital Signal Processor Analog Devices ADSP-21262 144 Lead LQFP Visual DSP++ Debugger & Evaluation Board Program Flash memory Atmel AT25F2048 2 Mbits in 8 bit words Used to store Instruction Memory SD Card socket User interface for loading FLAC files

  12. Schematic/Theory of Operation

  13. LCD Screen Crystalfontz CFAG12864B-TFH-V Built-in LCD Controller 128x64, B&W VIN minimum = 3.5 V SHARC can only guarantee 2.4 V Level Translators TI CD4504B, 3.3 V to 5 V For interfacing 3.3 V SHARC to LCD and D/A Schematic/Theory of Operation

  14. Schematic/Theory of Operation

  15. Schematic/Theory of Operation • Digital to Analog Converter • Analog Devices AD1854 • Delta-sigma type • Accepts 16/18/20/24 bit data; 96 kHz sample rate • I2S communication Protocol • 5 V, but 3.3 V input tolerant • Audio Operational Amplifier • Analog Devices SSM2135 • Used as headphone amplifier/buffer with low pass filter

  16. Schematic/Theory of Operation

  17. Voltage Regulators Design Requires 3 Voltage levels 5.0V provided by Linear Technology LT1302 3.3V provided by Texas Instruments TPS63030 1.2V provided by AME8890 Coulomb Counter LTC4150 Battery Gas Gauge Interrupt-Driven Operation Provides capacity to monitor bi-directional charge flow. Schematic/Theory of Operation

  18. Schematic/Theory of Operation

  19. PCB Layout Constrained by enclosure!

  20. PCB Layout

  21. PCB Layout LCD header & trimmer pots Program Flash SPI to Parallel Shft.R 3.3 to 5 V Boost Reset Button SD socket SHARC Audio output amplifier and passives D/A Power circuitry

  22. Software Requirements: • FLAC decoding • Already implemented in C • Most peripherals interface with SPI • Flash memory • SD Card • LCD Controller (special case) • D/A interface with I2C Serial • Visualization Computation

  23. Software Design – Other Functions Timer-Based Functions • LCD Screen Update • Output decoded data to D/A Interrupt-Based Functions • Coulomb Counting • User push-button interrupts Miscellaneous Functions • Requesting new data block from SD Card • Computing visualization information

  24. Project Completion Timeline • 25 March - Power circuitry functional (stable power supply, burn-in complete) • 1 April - DSP “Heartbeat” established, software loading functional • 3 April - Audio output circuitry complete • 8 April - FLAC decoding software functional • 10 April - LCD hardware & software functional • 17 April - Able to read files from SD Card • 24 April - All PSSCs implemented

  25. Questions / Discussion

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