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16. Downloading from the web server
b Principle
The Ethernet card has an embedded FTP server which authorizes access to the various URLs available for the HTTP server. A browser
such as Internet Explorer can be used to display the URLs like a disk in the Windows explorer. This “disk” consists of various directories
containing the URL files. It is therefore possible to use the different commands managed by Windows explorer such as deletion, renaming
or writing (downloading) files (check that card IO Scanning has been disabled).
b File management
The memory zone assigned to the web server URLs consists of 24 blocks:
• 23 sectors of 64 Kb for file storage.
• 1 sector of 64 Kb for the file table.
The web server storage capacity is 1.5 Mb, i.e. 1536 Kb.
The file table is used to make the link between the HTTP server, the FTP server and the various “URL” files. This table is dynamic and is
cleared and reprogrammed each time there is a change.
The maximum number of URL files is limited to 150.
The information relating to each file is as follows:
• File name (32 characters max.).
• Location address in the card memory.
• File size in bytes.
• “FTP” storage directory (html, html/lib/js etc.).
• URL processing function. (Access management, etc.). The URLs have a default function which requires a password (“HTTPpassword”)
in order to access them via HTTP, apart from a few exceptions (see below).
VW3A3310d Ethernet card
FTP server
File system
Write to
Flash memory
Read
Read
HTTP server
Internet
Explorer
PC