Technical information

W24 Embedded Web Server
2-78 AT+i Commands Reference Manual May 31, 2008
and queried using:
> AT+itemperature?
When the host issues a Set Parameter Tag Value command, W24 links the updated value to the
Parameter Tag and stores it in its internal RAM. In response to a browser's GET request, the real
value is substituted everywhere in the page where the Parameter Tag exists while the page is
being served, on-the-fly.
Parameter Tag values are printable ASCII text. This convention allows implementing any part of
an HTML or WAP page as a parameter tag: numeric values, links, file names, HTML code, etc. A
Parameter Tag value is limited to 256 characters.
Parameter Tag values can be changed and submitted from the browser end using HTML forms.
W24 stores the updated values and responds appropriately to host AT+i parameter query
commands. Thus, the host can poll specific parameters for value changes. Status Report 7
(AT+iRP7) can be used to facilitate polling on all application web parameters. RP7 returns a
bitmap result, where bit 10 is set to '1' if one or more application web parameters have been
remotely changed. The W24 DATA_RDY signal is an associated hardware signal that can be used
to generate an interrupt on the host CPU when new data has been buffered in W24. The ISR can
issue an RP7 to determine if the new data is a result of an application web parameter change.
The AT+iWNXT command can be issued to scan through the application web parameters that
have been remotely updated and not yet retrieved by the application.
The W24 application site is located at:
HTTP://<W24_IP_Address>/
Website Creation, Packing, and Uploading
Device manufacturers can design their own embedded website using any typical web authoring
tool. A website can include one or more files residing in a dedicated file directory structure on the
designer's PC. The topmost directory of this structure is referred to as the website root directory.
The root directory must contain an HTML page named index.htm, which serves as the default
home page.
Before downloading the website to a W24 device, the entire website needs to be packed. In order
to pack the site into an uploadable image file, the designer must run the web packing utility and
specify the root directory of the site. The utility packs all files in the root directory and its
subfolders in a format suitable for W24. If the site contains Parameter Tags, the user is prompted
to enter a maximum value length for each Parameter Tag. Any Parameter Tag specified with a
zero length value will not be included in the resulting packed file. After the user has entered all
parameters' max value length, the user is prompted to specify a destination for the packed file.
The following restrictions apply when creating the packed website:
• The length of a single Parameter Tag must not exceed 256 characters.
• The sum of all Parameter Tags' value lengths must not exceed 8K.
• The total packed file must not exceed 64K.
To take effect, the packed website file needs to be uploaded to W24. This is done through W24's
configuration website over the Internet.