Web 51 Applications
- Simple control of devices over TCP/IP...
- Communication module for your instruments...
- Interface that can handle any protocol...
- Collecting of data and making them available over a network...
- Extension of a RS 232/422/485 serial port...
- Connection of common appliances to a computer network...
Basic capabilities of Web51 are demonstrated on an example that simply converts serial line communication to TCP/IP based communication and vice versa. In practice, Web51 is connected to a network, and any computer on the same network can communicate over Web51's serial line using a telnet application. Web51 makes communicating over the network similar to using Hyperterminal to talk to a PC's local serial port.
The Project description implies several limitations of the possible applications, mainly in hardware.
- In the basic version, CPU AT89C8252 = 8 kB FLASH / 256 bytes RAM / 2 kB EEPROM. (Not much.)
- Possibly CPU T89CRD2 = 64 kB FLASH / 1280 bytes RAM / 2 kB EEPROM.
- Basic communication modules of Web51 take up about 4 kB FLASH - the rest is free for HTML pages or the application itself.
- External EEPROM can contain other HTML pages etc., up to the filesystem limits.
- 16 I/O lines are available to the user (entire P1, part of P3, two pins of P2). However, these 16 lines include I2C bus, RS232, or onboard buttons and LEDs if used. All of them are accessible via the PFL34 connector.
- Full version of Web51 is ideal for series of at least 20 to 50 instances of a particular application, since the simple hardware decreases cost but increases development time.
- For smaller series, LITE version can sometimes be used. Application can be controled over RS232. Details about the LITE versions are in Project description.
- Web51 is not intended for bandwidth over 50-100 kbit/s.
- Input variables (pin status, RS232, or specialized devices) can be embedded into a HTML page
- Supports .JPG and .GIF images (small Flash is a limit, though)
- Supports internal CGI scripts in HTML
- Extensive library of examples
- It is possible to add custom scripts
- Basic "Telnet" server listening at port 23. Carries data from an open TCP/IP connection to the serial line, and vice versa.
- "Active Telnet" - a client that establishes a TCP/IP connection as above if none is open.
Telnet supports both passive and active connection (can be disabled). Unlike the WWW server, it fully supports retransmission of lost or corrupted packets. However, if the memory runs out while waiting for acknowledgements, communication slows down. Connection is automatically closed approximately 50 seconds from the last received acknowledgement.
Web51 contains one TCP stack for each port. It is possible to have two connections open at the same time, one on each port.
- Sends e-mail according to a given input condition.
- E-mail is fully textual, conditions are used to modify contained strings.
- E-mail is sent through the specified SMTP server.
- Ideal for logging device status, etc.
After reading Project description, you can surely think of more applications of Web51.
- Standard TEA algorithm with 128-bit key.
- Support for mutual authorisation of operations.
- Typical usage of OTP (One Time Paswords).
- TEA control may be used = authorisation from Java scripts.
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