EM-1220 LX User’s Manual
Software Package
EM-1220-LX Software Architecture
The pre-installed µClinux operating system used by the EM-1220-LX follows the standard
µClinux architecture. This means that programs following the POSIX standard are easily ported to
the EM-1220-LX with the GNU Tool Chain provided by www.uClinux.org. In addition to the
Standard POSIX API, device drivers for the buzzer and UART for the serial ports are also
included.
The EM-1220-LX’s Flash ROM is divided into smaller partitions, including the Boot Loader,
Linux Kernel & Root (/) File System Image, and User Directory partitions.
For most applications, users often spend a lot
time maintaining the operating system and
modifying the system configuration. In order to
save on the total cost of development and
maintenance, the EM-1220-LX is specially
designed to partition a “User Directory” for
storing the user’s system configuration
parameters.
The EM-1220-LX has a built-in mechanism that
prevents system crashes to help preserve system
reliability. The procedure is described below.
When the Linux kernel boots up, the kernel mounts the root file system and then enables services
and daemons. The kernel also looks for system configuration parameters via rc or inittab.
User AP
User Directory
(User Configuration)
Mini Root File System
Configuration
Linux Kernel & Root
HW
Boot Loader
Normally, the kernel uses the User Directory to boot up the system. The kernel will only use the
default configuration _etc & _home when the User Directory crashes.
The EM-1220-LX uses ROMFS for the Linux kernel image, Root File System, and Protected
configuration, and uses JFFS2 for the User Directory.
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