Final Presentation

1
Final Presentation

• April 13, 2004

2
Project Results

• Operating System
• Web Based Interface
• MP3 Decoding
• Stereo Sound Output

3
Operating System

• uClinux
• File System
• Pre-built applications
• tftp, thttpd, top
• Debug tools
• Examine files ls, cat, more, vi
• Log files
• Powerful development environment
• bootloader, example code

4
Web based interface

• thttpd web server
• CGI based dynamic web pages
• Decode, play, stop controls
• Fast upload and download capability
• 1.3 Mbps upload
• 2.2 Mbps download
• Multiple Upload/Download capability

5
MP3 decoding

• MAD algorithm
• Decodes all sample frequencies
• 32 kHz, 44.1 kHz, 48 kHz
• decodeMP3 user application
• Compiled with Kernel
• Audio module
• File Interface
• Copy from User to Kernel Space
• 6MB buffer

6
Stereo Sound Output

• PCM1770 Digital-to-analog converter
• Hardware DAC controller
• Huge FIFO (512 x 32) (4ms of sound)
• Buffer wrapping
• Audio Interface
• Linux kernel device driver
• Interrupt service routine

7
Strengths

• Versatility uClinux gives easy portability for
  other applications.
• File system
• thttpd Secure, stable web server
• Large Hardware Buffer (512 x 32)

8
Weaknesses

• Interrupt latency bug
• Multiple data copies
• uClinux Memory usage
• High kernel overhead
• 50 kernel processor time

9
Novel Features

• Debug features (cat /proc/interrupts)
• Fast Flash updates tftp
• Bootloader
• Additional applications (top, games, etc)
• Usable for true commercial products

10
Next Three Weeks

• Real time MP3 decoding and playing
• MAD optimization
• Improve memory usage
• File system size
• Larger buffer OR reverse FSL link
• Improved CGI functionality
• Polish the interface
• Network File System (NFS)
• Play files directly over the network