Building an audio player using the Texas Instruments OMAP-L137

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Building an audio player using the

Texas Instruments OMAP-L137

with LinuxLink 3 0

with LinuxLink 3.0

Webinar Series

Building a custom system with

Session 2

Building a custom system with

audio playback functionality

We will start our webinar in few minutes. Thank you for your patience

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Series Overview

Session 1

Assembling a small footprint Linux platform for the

OMAP-L137

Session 2 – today

Building a custom system with audio playback

functionality

Session 3 – September 10, 2009 11:30am EST

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Agenda – Session 2

Recap of what we have done so far

Modify the Linux kernel

• Reconfigure to add support for Bluetooth

Modify RFS design

• Add packages for audio playback with codecs for desired media playback • Add Web server

• Use overlay to deploy custom codeUse overlay to deploy custom code • Enable Bluetooth

Create a custom content for a Web server

• Create an HTML static page

• Create CGI scripts for audio playback

Create a RFS overlay with modifications

• Web content

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What we have accomplished so far

Built a starting point with Online Factory

• Experiment on day one with a pre-built starting point

Modified Linux kernel using desktop tools

• Optimized for footprint

O i i d f f b

• Optimized for fast boot

Altered root filesystem

• Removed unneeded startup scripts

Deployed the system on target with network mounted

RFS

• Transferred images via TFTP

• Configured bootloader for autobootg

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Browsing the kernel sources

GIT is … part of the update service

• Git is an open source, distributed version control system

currently used by a number of projects including: currently used by a number of projects including:

– Kernel.org – X.org

– Perl – Android

• Every Git clone is a full-fledged repository with complete

history and full revision tracking capabilities

B hi g d gi g f t d t d

• Branching and merging are fast and easy to do

Timesys GIT

• Provides code for a number of TI’s platforms, including:

¾ OMAP-35x ¾ OMAP-L137 ¾DM355 ¾DM6446 https://linuxlink.timesys.com/git?repo=linux-2.6-davinci.git https://linuxlink.timesys.com/git?repo=linux-2.6-omap.git

READ more on the GIT update service here:

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Platform adjustments

Linux kernel

• Linux kernel configuration

E bl b t t ( i tk)

– Enable verbose output (printk) – Enable audio

– Enable Bluetooth (for future use)

Desktop factory command: # make kernel-menuconfig

Root filesystem

• Add the following packages to the RFS definition

– alsa-utils – alsa-utils – thttpd – haserl

– bluez-utils (for future use)( ) – mplayer

– (codecs)

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Custom Code for the Web server

Static web page

• Provide a static index.html

B tt t l b k di

– Button to playback audio

CGI script for audio playback

• Sections

– Calls haserl to translate to a web page – Lists all audio files at an assumed location – Allows to stop the playback

– Starts a media player with selected stream

Create an overlay that includes the following:

• Create a tar file with overlay directory structure • Create a tar file with overlay directory structure

Using desktop factory merge the overlay into the

system’s RFS

y

• Using Desktop Factory navigate to:

– Target Configuration->Build RFS->RFS Content Tarball

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Deployment

We’ll use TFTP service to transfer images to the target

• Runs typically as xinetd process

Di bl d h l i t ll d M dif / t / i td d/tft d

• Disabled when newly installed. Modify /etc/xinetd.d/tftpd

Setup NFS to mount RFS via network for initial

development

• Runs as a daemon on your host

• Export FS via /etc/exportsp / / p

• Restart the NFS server via /etc/init.d/nfs service

Assign a static address or use dhcp

Bootloader setup procedure

setenv bootdelay 3

setenv bootfile uImage

setenv bootargs mem=32M console=ttyS2,115200n8 root=/dev/nfs rw ip=dhcp setenv bootcmd dhcp;bootmp

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What we have accomplished today

Modified our design to

• Enable audio

Add W b

• Add Web server

• Add media playback capability

A hi d b

Achieved by

• Device driver enablement

• Root filesystem adjustments

Added contents for the web server

• Static html page

• CGI script to playback audio files

System deployment

• Deploy an overlay onto our system RFS

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Next Time

Session #3 is scheduled for Thursday, September 10th

at 11:30am EST

Subject: System debugging and testing with the

OMAP-L137

OMAP L137

• Test additional technologies: i.e. Bluetooth

• Build our system for debugging

• Remotely debug application e ote y debug app cat o

• Verify the quality of the solution with a testware

S t i htl b ild t b d th D kt F t

• Setup nightly build system based on the Desktop Factory

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How Do I Learn More?

Go to

www.timesys.com

to learn more

• Webinars

• LinuxLink Radio Podcasts

• Request a Free Factory Test Drive

Schedule a more detailed introduction/training

session

• WebEx