The EtherSmart Wildcard User Guide
Table of ContentsAppendix G: Hardware Schematic (pdf)
You’ll use a web browser running on your PC to interact with the web server running on the EtherSmart Wildcard. Popular browsers include Microsoft Internet Explorer, Netscape based browsers such as Firefox and Mozilla, and other high quality free browsers such as Opera. All of these browsers work with the web demonstration program that comes with the EtherSmart Wildcard (see the demonstration program source code listings at the end of this document).
Additional considerations can limit the performance of some of these browsers if your application needs to serve out more complex web pages that require more than one TCP/IP connection per web page. This can occur, for example, when mixed text and image data originating from the XPort are served out in a single web page.
The Lantronix XPort hardware on the EtherSmart Wildcard supports only one active connection at a time. However, the HTTP/1.1 standard (and consequently all browsers in their default configuration) expect the webserver to be able to host two simultaneous connections. A default-configured browser will try to open a second connection when two or more content types (for example, HTML text and a JPEG image) are present in a single web page. The second connection will typically be refused by the XPort hardware, causing an incomplete page load. The solution is to configure the browser to expect only one connection from the webserver.
Appendix F explains how to reconfigure Internet Explorer to work with any web page that the EtherSmart can serve out. For the best solution, though, consider downloading the free Opera browser and using it for all your interactions with the EtherSmart Wildcard.
To be able to browse mixed text and graphics pages from the EtherSmart Wildcard without modifying your default browser, go to www.opera.com and download the latest version of the Opera browser for Windows desktop machines. It's free, the download file is compact, and the install takes only a few seconds.
Simply go to www.opera.com and select "Download Opera", then double-click on the resulting file to install the browser on your desktop. It is very easy to configure Opera for the EtherSmart webserver. Once Opera is installed, simply go to its Tools menu, and select:
Preferences->Advanced->Network->Max Connections Per Server
and enter 1 in the box. Now you’re ready to use Opera with the EtherSmart Wildcard dynamic webserver. The webserver is described in more detail in a later section.
During program development and testing of the EtherSmart Wildcard, it is very useful to be able to interact with the Wildcard using an Ethernet terminal program. A popular option is the "Putty" program, a simple and small freeware program that can be downloaded from the web.
To obtain the free Putty Ethernet terminal program, type
into your search engine (such as Google) and download the executable program from one of the listed sites. It is a simple yet generally useful program.
When you double-click on the Putty desktop icon, a configuration screen appears with a box for the "Host Name or IP address" and another box for the port number. For example, if your EtherSmart Wildcard has an IP address of 10.0.1.22 and uses the standard local port value of 80, simply type these values into the appropriate boxes.
A set of radio buttons on the Putty configuration screen allows you to select one of four protocols: "Raw", "Telnet", "Rlogin", and "SSH". The "Raw" mode is a straightforward implementation of a TCP/IP connection, and is recommended for the Tunnel_Test function in the demo program as described in the section below titled "Serial Tunneling". This test shows how to programmatically control transmission and reception of data over an Ethernet link.
"Telnet" is very similar to raw mode, but sends a line of configuration bytes at the start of the session that passes through the XPort device to the controller. For this reason, the Raw mode is superior to Telnet for use with the EtherSmart Wildcard. The Telnet configuration bytes have the most significant bit set, and can be filtered out by an application program by passing the appropriate flags to routines such as Ether_Add_Chars, Ether_Add_Line, Ether_Get_Chars, Ether_Get_Line, or by using Ether_ASCII_Key or E_ASCII_Key. These functions are discussed in the "Serial Tunneling" section below.
The revectored serial via Ethernet test is best conducted using Putty’s "Rlogin" mode. The Rlogin protocol mimics the echo and carriage return handling of the standard QEDTerm serial terminal, and so is perfect for performing code downloads and interactive testing with Ethernet replacing the serial port. This capability is described in the "Code Downloads and Interactive Communications via Ethernet" section below.
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