Web51 - Basic description
Web51 is a complex project of connecting an Intel x51 compatible processor to a Realtek RTL8019AS network controller. The result is a very low-cost Ethernet interface. Since a well-known x51 architecture is used, even small and medium-scale businesses can now network their devices.
The goal of this system is to provide a low-cost platform for applications with low hardware requirements, e.g. telemetry. Extension of a RS232/422/485 link is nearing the upper limit of the performance capabilities. The solution drives hardware costs down at the expense of more complicated development of applications. Taking into account costs of hiring developers etc., Web51 is useful for series of at least 20 to 50 instances of a particular application. Development of application software in assembly might be a disadvantage; however, it is not necessarily a problem for simple applications. In addition, the development kit includes a wide range of examples that present some of the system capabilities and can help you to learn the system quickly.
The x51 compatible processor, in our case a 89C8252, is used in port mode only. The application does not need a 74 373 (or 74 573) latch since there is no address bus to create. The 89C8252 was chosen because it has 8kB of program FLASH programmable through ISP, which streamlines development, and 2 kB of internal EEPROM. Generally, any x51/x52 clone can be used. For other processors, some modifications of the preconstructed TCP/IP headers and the Ethernet controller driver code might be needed. Ethernet interface is provided through a standard RJ45 connector, although the board can provide AUI as well - for example, to connect an optic fiber media convertor. The 10BaseT part uses standard circuit including denoising HV capacitors that suppress voltage spikes. Processor, or the entire board, is reset by a DS1833, software is guarded by the internal 89C8252 watchdog.
Details are in the Web51 schematic (a part of the docs).
If you plan to program the processor over ISP, make sure that RESET and the programming sequence don't interfere with peripherals.
Web51 Software is very large and consists of a number of source files and libraries. To avoid compilation of the entire project every time, the "make" utility is used to manage the sources and compile them. Assembler and linker from the GNU BINUTILS package were enhanced to support x51 processor. They run on both Linux and Win32, as well as on many other platforms. A number of other GNU tools are also used.Related topics:
|Web51 description||News||FAQ||ORDER FORM||DOWNLOAD||Links|
|(c)Copyright 2000 - 2002, HW server & Radek Benedikt