Description

OpenEZ is an open source, multi-tasking operating system with a built in TCP/IP stack. The TCP/IP stack is a version of LwIP specifically ported for the eZ80 with the CS8900A Ethernet chip. LwIP is released under a BSD-style license and my port of that code released under those same terms. The rest of my OS code is released under the GPL license. This means all the software here is free for you to use, including for commercial purposes, provided you make available any derived works that you create on that same basis. If you need a different license for the OS, get in touch with me and perhaps something can be worked out.

Features

Multi-tasking operating system, designed for the eZ80 and optimized for embedded systems.
Mutex functionality, similar to Linux threads recursive mutexes.
TimerQueue feature adds unlimited callback scheduling, with millisecond precision. Makes it easy to schedule something to happen after a delay while the task goes ahead with other work. Callbacks can be scheduled to occur once, or to repeat at the selected interval indefinitely.
msleep() function to put a task to sleep for a given number of milliseconds
Extremely fast dispatcher / scheduler supports by-task priority and time slicing.
Tasks can be set to run within a time slice, until voluntarily giving up control, event driven or a combination of these.
Tasks can be dynamically created and ended, or started at system initialization and run unendingly
Each task has it’s own stdin, stdout and stderr streams, which can be directed to a UART or a TCP/IP port. Multiple tasks can share the same output stream. Tasks can operate with no stdio streams, as well.
Included are interrupt drivers for UARTs, Timer0 (1000 interrupts/sec), Timer1 (time slice timing) and RTC (1 interrupt/sec)
Built in HTTP, Telnet, Echo, and ping servers,
Utilities provided for decoding HTML requests, whether GET or POST method.
Supports login by username/password. Partial telnet negotiation, passwords not echoed, for example.
Optional DHCP client for dynamic IP configuring
Built in Shell: dump, load memory, set time, date, view I/O registers, presently 18 commands and growing.
Proven IP stack ported from the open source LwIP project
Driver for the CS8900A Ethernet chip, runs in the polled mode as recommended by Crystal.
Routines provided for writing and erasing flash memory.
Comes configured for the L92 version of the Zilog development platform, but easily adjusted for other memory-I/O configurations
Less than 100KB of code, for everything. Unused software routines automatically omitted for an even smaller footprint.
Extensive security functions included: AES, Blowfish, SHA-1, MD5, HMAC-MD5, HMAC-SHA-1
All source code is available

More Information

To Do List / Wish List / Future Plans

Add kill <pid> command to shell
Add PPP support for transmissions over the serial ports
Let me know if you see something you need that is missing. I would also be happy to have a few experienced programmers join in the development process. OpenEZ will be better if several people contribute to it and are testing the code to ensure it’s the best it can be.

Links / Resources

Zilog eZ80 user group’s home page
eZ80 Public Discussion board
An Embeddable HTTP Server, the starting point for the httpd server in OpenEZ
Home page for LwIP, the stack used in OpenEZ
Web site for LwIP downloads
Home page for DHCP and CS8900 driver, DHCP used as is in OpenEZ, CS8900 driver was rewritten for 8 bit.
Cirrus Logic page on the CS8900A Ethernet chip documentation
Page to download the Cirrus Logic 8 bit sample driver for the CS8900A. This was used as a guide for writing the OpenEZ driver.
Application notes regarding the CS8900A from Cirrus Logic
Product specs for Micron Flash Memory MT28F800B3

This project is supported by

Robert Laughlin

Digital Systems Corp

Walkersville, Maryland, USA