duel-line RS232 interface
The software package includes embedded Linux operating system, device driver package, embedded graphic package, GNU cross compiler and debugger. Embedded Linux operating system includes embedded Linux core, ROM/RAM document system. The core uses the popular open sourced embedded Linux-cLinux.
The system structure of Embedded Linux software development platform is shown in the figure below. The parts surrounded by dot lines are going to be supported in the next release.
Introduction of embedded Linux operating system.
The core of the embedded Linux system implemented on this platform is based on the world wide known embedded Linux - cLinux. This embedded Linux system is oriented towards embedded operating systems that have a CPU without MMC support. The core expands from Linux 2.0 kernel and supports Linux Kernel Version 2.0.X right now.
This embedded Linux operating system use a generic Linux API- the standard Posix interface. The embedded Linux OS kernel is less than 512KB. Kernel and tools(fs) are less than 900kB.
This embedded Linux operating system has powerful network functions. It supports PPP, Ethernet and several other network connection methods including complete TCP/IP protocol. Currently, supports for many network protocols are in development. Since Linux is an open OS, new protocols can be easily added into the system core.
This embedded Linux operating system supports many external devices. Currently at the system core level, many external devices support is implemented, including LCD, touch screen, keyboard, multi-line serial port, modem, IrDA, PWM sound output, etc. At the same time, the core supports many document systems: ROM-Disk, Ram-Disk, NFS, ext2, FAT16/32, etc.
Embedded GUI graphic packages based on MicroWindows
Embedded GUI graphic package provides ample graphic functions, including advanced functions such as Alpha mixture, 3D support, TrueType font support. It also has localized Chinese support, including GB2312 support, Chinese input method etc.
Embedded GUI graphic package can be used directly on the embedded Linux Operating system. In the 32 bit system, typical application with one type of font needs about 100K space.
Embedded GUI graphic package provides two types of interfaces for the software application developers: Win32 and Nano-X APIs. They have the same interface as the ones used in Windows and X-windows. Developers with experiences in Win32 and Nano-X development can develop embedded graphics software with ease.
Embedded GUI graphic package includes an X11 driver. It allows embedded GUI software applications to be executed in X windows. This driver imitates the embedded environment display and ignores the display characteristic of the desktop. It lets the display characteristics of the target system to be previewed directly on the desktop. Thus provides a great simulated environment for the users to develop embedded graphical software applications. Developers develop software on the X Windows desktop systems and debug embedded graphics software applications. After the defects have been removed, software can be debugged directly on the target system. This method can increase speed and save the time of the development significantly.
The following functions have been implemented.
1. Embedded GUI widget: Implemented based on FLTK. Supports many types of GUI control such as menu, button, and scroll bar etc.
2． Embedded web server: Supports CGI.
3． Chinese handwriting input: Provides complete Chinese input solution for the customers by integrating third party Chinese handwriting input software.
Cross compile and debug tool kit
To support a new processor, tools such as compiler, assembler and debugger are required to generate binaries files executed on the processor. This embedded Linux development platform uses GNU development tool kit including a series of development, compile and debug tools. It is free to our customers and helps them to build their own software application development environment quickly.
The main components included
GCC: Compiler can be used as a cross compiler. Users can develop and compile binary files on the host machine.
Binutils: Supporting tools, including objump (disassembler), as (assembly compiler), ld (link device), etc.
GDB: debugger. Uses remote cross compile method on COM2, including gdbserver (target system), gdb (local host)
Download tool: It is to download the executive files that operate in the object machine from the host to the object machine and also a coupling tool with gdb.
Linux print terminal: Usually the default terminal uses serial port. Kernel prints all information to terminal through serial port. At the same time, developers interact with system through this terminal.
The development environment under Embedded Linux:
The main environment of embedded Linux development platform's GNU development tool kit is desktop Linux. Red Hat 6.x is recommended. The desktop Linux is the platform on which the embedded Linux applications are developed. The development tool kit consists of cross compiler (GCC), utilities, debugger (GDB) and download tool that includes 'send' which runs on the desktop Linux and 'receive' which runs on the object machine and GDBSERVER.
The debugger uses serial port 2. Serial port 1 connects the simulated terminal on the host to the object machine. The main method of debugging is to debug the executive file remotely that runs in the object machine through serial port; The gdbserver on the object machine receives the control commands from gdb running on the host and controls this executive program then returns the state information to gdb through serial port.
Embedded Linux real time solution
The uClinux hasn't solved the real time problem itself because its purpose isn't to solve this kind problem. Instead, we use Rt-Linux to solve this problem. In RT-Linux processor manager's point of view, the Linux kernel is just like an ordinary task. Of course, RT-Linux processor manager also handles other real time process and non-real time processes will be handled by Linux kernel. This method is used to improve the real time performance of this operating system. Such systems include commercial UNIX and window NT and so on. The uClinux with supporting real time process may support hard clock and widely used to applications such as the industrial control and process control and so on.
The picture of development platform.
Commercial cooperative model:
Neusoft will cooperate with our clients in many different commercial cooperative models. At present, following are the models:
1．Neusoft provides this embedded software development platform to embedded system developers and take the responsibility to train them.
2．Neusoft can migrate the embedded operating system to client's object system and develop the device drivers according to demand.
3．The clients will be charged for our software platform after having developed their products on our platform. The price and other details can be negotiated.
4．Neusoft provides integrated solution that consists of product design including hardware design, development which includes system software development and applications development for our clients. And the clients will be charged for our solution.
