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RL-ARM User's Guide (MDK v4)

RL-RTX RL-FlashFS RL-TCPnet TCP Socket Opening TCP Connection TCP Active Open TCP Passive Open Sending TCP Data Example for Sending Data Multiple TCP Connections UDP Socket Opening UDP Connection Sending UDP Data When DHCP Enabled When ARP Cache Empty Example for Sending Data IP Multicasting Multiple UDP Connections Configuring RL-TCPnet Static Configuration System Definitions Ethernet Network Interface PPP Network Interface SLIP Network Interface UDP Socket TCP Socket BSD Socket HTTP Server Telnet Server TFTP Server TFTP Client FTP Server FTP Client DNS Client SMTP Client SNMP Agent SNTP Client Error Function Runtime Configuration Library Files Using RL-TCPnet Stand Alone With RTX Kernel Event Driven Operation IP Address Assignment Ethernet Interface PPP Interface SLIP Interface Localhost Applications HTTP Server Script Language CGI Functions Ajax Support Using XML XML Example How it works SOAP Support SOAP Interface Large POST Messages Web Pages Default Page Error Pages Web on SD Card Web Update File System Interface Http Caching How it works Internal Web External Web Multi-user Authentication Using RAM File System FCARM File Converter PRINT Directive NOPRINT Directive PAGEWIDTH Directive PAGELENGTH Directive ROOT Directive Telnet Server Command Line Interface Multi-user Authentication Sending Reply Message Short Reply Long Reply Continuous Screen Update TFTP Server File System Interface TFTP Client File System Interface FTP Server File System Interface Multi-user Authentication Supported Commands FTP Client File System Interface SMTP Client SNMP Agent MIB Database MIB Interface MIB Entry MIB Table DNS Resolver Starting DNS Device Drivers Ethernet Driver Interrupt Mode Modem Driver Serial Driver Using Serial Link Cable Connection Modem Connection Windows Dial-up Add Direct Serial Link New Dial-up Connection Configure PPP Dial-up Configure SLIP Dial-up Debugging Enabling Debug Debug Level Redirecting Output Function Overview BSD Routines CGI Routines Ethernet Routines FTP Routines HTTP Routines IGMP Routines Miscellaneous Routines Modem Routines PPP Routines Serial Routines SLIP Routines SMTP Routines SNMP Routines System Functions TCP Routines Telnet Routines TFTP Routines UDP Routines RL-CAN RL-USB Example Programs Library Reference Appendix

External Web

The Web server also supports the browser local caching of Web pages stored on SD Card at the Web server. In general the files on SD Card are bigger, and so the performance gain, much better. The space, available for Internal Web pages is limited with the size of internal flash memory. So all large images, java script archives and other large web resources, have to be located on externally attached SD Card.

Static Web Resources

The static web resource files are copied to SD Card when the application is built and are not modified later. You might use the SD Card Reader attached to PC to copy the files. In this case, the file modification date is set correctly by the PC. If you use an embedded application to copy the files, the file modification date is most likely set to the FlashFS default time. This however does not create any problems in browser local caching. Once the web is locally cached by the browser, the cache is always valid and is used in subsequent browser requests.

Using Web Update

Web resource files, which are updated later with one of the update options provided by RL-TCPnet, are dynamic Web resource files. You must provide the file modification date and time to the Flash File System. If this information is not available, the FlashFS uses a default file modification time. This might create troubles in local caching by the browser.

If you upload an updated web page to the server, but the FlashFS adds a default file modification date, the Web server is not able to recognize the updated files. It always reports the same Last-Modified date. The the browser then uses locally cached, but outdated web resources instead of the updated ones.

To load the updated web page in the browser, you have to manually clear the cache in the browser first and then reload the web page again.


  • If the FlashFS does not have a Real Time Clock information, the Web Server will not work for updated Web pages.
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