E-CPU-1000 Series / Software on board
Our ARM-9 CPU-modules will be deliverd with a boot-loader (U-Boot), a Linux-kernel and a file system.
All the software modules are also pre-configurated and compiled at the flash memory of the CPU board. Of course you will be able to modify and compile the modules if necessary.
In the following we will go into more detail about the modules:
The Boot-Loader U-BOOT
After turning-on the supply voltage the bootloader U-BOOT will be loaded and started from FLASH. It waits 3 seconds to see if there is an input from the user to hold the furthermore bootsequence.
If there is no input the bootloader starts the Linux kernel and beginns to execute it.
If the bootloader is aborted by input, it starts a commandlinetool able to execute several commands.
- Administrating of environment variables. These can be created, changed and saved to the socalled "Enviroment"-area at the FLASH chip of the CPU board.
- Files can be loaded by TFTP-protokoll from a TFTP-server.For example this could be a new Linux-kernel or a new filesystem.
- Writing the FLASH by command. This way a kernelupdate, loaded by TFTP before, can be writen to the FLASH at the CPU board.
- Executing of loaded programms. This way you are able to load a new kernel via TFTP (without updating the FLASH) and to test it.
The Linux-kernel
The Linux kernel holds the software- hardware interfaces. They realise the Hardware-adressing e.g. for the ethernet controller, the serial interfaces and much more.
The file system
The filesystem includes the whole file directory tree, as well as all executable programms at compiled form. The file system is loaded to the FLASH as a JFFS2-file and then unpacked to a "ramdisk". This way the Programms aviability is very high and its not needed to read them from the "slower" FLASH.