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THE eZ80 WEBSERVER

An 8-Bit CPU Takes on the Internet

by James Antonakos

Start ý Software Model ý Memory Map ý Instruction Set ý On-Chip Peripheral Registers ý Hardware Architecture ý TCP/IP Stack Operation ý eZ80 Evaluation Board ý Connecting the System ý Developing the Hardware and Software ý Application: A Web-Based Security System ý Other Applications ý Win Your Own! ý Sources and PDF

This month, Iým doing what I enjoy most, playing with new hardware and software. Even though it is brand new, there is an air of familiarity about my interest this month, which is Zilogýs new eZ80 Webserver microprocessor.

Zilog took its 8-bit Z80 microprocessor and supercharged it with many new features. Included is 50-MHz clock speed; 16-MB memory addressing space (along with the familiar 64 KB of the original Z80); pipelined fetch, decode, and execute logic; 8-, 16-, and 24-bit registers; Ethernet connectivity; support for TCP/IP; programmable timer/counters; built-in DMA and serial I/O; and 32 bits of programmable I/O.

I believe that there are still many applications that can be implemented using 8-bit processor technology. For example, itýs a waste to put a 500-MHz Pentium III processor inside a robot arm that will just be spraying red paint on a door all day long. An 8-bit CPU, like the eZ80 Webserver, is powerful enough to perform the required axis movement calculations for the robot arm. And, best of all, the arm can be networked with the eZ80, making it easy to download a new paint program into it or run an online, web-based diagnostic.

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