Embedded Linux

1
Embedded Linux

• CS-423
• Dick Steflik

2
Desktop vs. Embedded

• GUI
• Lots of User Apps
• Full complement of device drivers
• Lots of memory
• Hard drive, CD,DVD, USB, printer, mouse and
  keyboard support standard

• No GUI
• Linux kernel
• Typically Busybox rather than user apps
• Bootstrap Loader
• Some memory
• TTY support
• Flash or MMC support

3
Embedded Distributions

• UCLinux - www.uclinux.org
• BlueCatLinux LynuxWorks
• MontaVista Linux
• VxWorks, Wind River Systems
• QNX Quantum Systems
• Linux Embedded
• OpenMoko FIC

4
Kernel Ports

• X86 - www.kernel.org
• ARM - www.arm.linux.org.uk/developer
• PowerPC penguinppc.org
• MIPS - www.linux-mips.org
• SuperH linuxsh.sourceforge.org
• M68K - www.linux-m68k.org

5
Your Embedded System

• For optimum performance you must configure your
  kernel for your hardware
• How To Configure a Kernel
• http//www.faqs.org/docs/Linux-HOWTO/Kernel-HOWTO.
  htm
• NGW100 is already configured for all of the NGW
  features
• USB, Ethernet, SD/MMC
• May have to build a new kernel to add GPIO,
  USARTS,I2C and LCD

6
Your Embedded System

• In general
• Only configure for the specific hardware you are
  going to use
• You may configure options that serve your
  development needs (RS-232, SPI), but in final
  build for production rebuild kernel with only
  what you absolutely need
• If you may need to do updates make sure that you
  have a build that supports your download path

7
Four Main Configuration Options

• make config
• Command line interface that asks you about each
  option
• make oldconfig
• Uses an existing .config file and prompts you for
  only the options not previously configured
• make menuconfig
• Displays a curses-based configuration menu, if a
  .config file is present it uses it for defaults
• make xconfig
• Displays a Tk-based X Windows GUI

8
AVR32 Kernel Config and Compile

• http//www.avr32linux.org/twiki/bin/view/Main/Comp
  ilingTheKernel