eZ80 Remote Access

The eZ80 Webserver is a powerful connectivity engine, it is a complex system as well. This chapter describes how the Remote Access software is made to simplify the user geting along with the eZ80 Webserver to achieve the advantages listed in the General Overview.

To enable flexible server configuration the configuration data is organized as a special configuration file. This file is stored in the flash memory of the eZ80 Development Board. After a reset during the boot phase the server initialization occurs according to the date stored there. The server thus starts with a proper most recent configuration.

The Metro IPWorks TCP/IP stack is running on the operating system named XINU. This is a real time multitasking OS. The Remote Access server software is basically implemented as a process of XINU. To start this process the firmware calls the ra_init() function. This hides most of stack level APIs from the user and enables the connectivity.

Indeed it enables the following:

• the datagram command server is started. The Server accepts UDP connections on port 3000. Port 3000 of the server is called a control port. It is used by Client for passing commands in ASCII format to the Server and receiving literal responses consisting of a code number and a verbal answer from the server. The Server parses the commands and performs accordingly. For example, once the Server received a scan command, it reports its IP address and EMAC address to the client.
• the Server supports a configuration file management. Client can command to read and store the configuration to the flash. This requires binary data transfer to be performed. For this purpose TCP connection oriented transaction on port 3001 is used.
• for different application purposes, such as webfile transfer, or firmware download, the other commands are used and the callback functions for those commands are implemented on the Server side to make the commands work. Thus the Server application is flexible and the user can add custom commands to manage the eZ80 Webserver.

The client part of the Server Update software implements the user interface and supports the interface protocol to the Server. The Client accesses the server by its IP address through port 3000. Each transaction between client and server begins with the client sending one of the control commands. For the description of the control command protocol see the Control Socket Functions section.