Incorporating Internet features into a new product under development presents exciting challenges to embedded engineers.

by Craig Borax, Tidal Engineering Corp.

Despite the draw of Internet dating, investing and free music downloads, embedded devices are getting online even faster than people. From Internet monitoring of instruments, process control and air conditioners, embedded devices use the Internet to provide greater value without substantially increasing costs.

Environmental test chambers, building temperature monitoring systems and Internet cameras are all products that are now found with Internet capabilities.

From manufacturing to personal uses, remote control and data acquisition applications have benefited substantially from this trend. The Internet connected refrigerator, picture frame, camera and test instrument are out of the R&D lab in a big way.

Many embedded engineers will be finding themselves tasked with incorporating these Internet features into a product they are designing, that is if they haven't already. This presents a new and exciting challenge to many embedded engineers.

Engineers doing embedded software and hardware usually work in small teams with familiar tools. In some instances, many software engineers single-handedly write all the code for the project. Although available for nearly every processor, Real-Time Operating Systems (RTOS) aren't often desired or affordable.

Networked devices require a gaggle of unfamiliar services like the TCP/IP stack and server applications including HTTP, FTP, DNS, SMTP, PPP, SLIP, DHCP, IP, TCP and UDP. Thus, many embedded engineers will face a considerable challenge developing the new wave of devices.

These new software components are fairly substantial, relatively new to the embedded engineer and typically require much more computing horsepower than systems without these features. In most cases, developing any of these components from scratch does not make sense when considering time-to-market and cost requirements.

Integrated circuit, software and system vendors are happily working to help the engineer face this challenge and bridge the gap with modules, boards and software tools. Products are being introduced every day that make the power of the Internet more accessible to the embedded engineer who spends his hours "bit-banging" peripherals, and even those who have never used an RTOS before can now deliver his product.

Software is the most difficult challenge when designing an embedded network and several approaches are available for solving it. Desktop Operating System (OS) vendors have been working to shrink their products to fit comfortably in small embedded systems. Of these, Microsoft's Windows CE is a popular choice for medium to large embedded systems. Though often requiring a fairly powerful CPU and substantial memory, Windows CE is a complete solution with its Graphical User Interface, Real-Time performance, Networking and professional development tools.

The increasingly popular open source Linux operating system is available from many vendors offering real-time extensions and tools for embedded applications. Companies like Lineo, Red Hat, MontaVista Software and Linux Devices are a few that offer Linux embedded tools and support. Of course, open-source networking software and applications are available for Linux.

In addition to the OS, Web server software is being made available from a wide range of sources. Recently, Tim John presented a compact embeddable Web-server written in 400 lines of C. (Dr. Dobbs Journal, September 2001).

Another offering is the GoAhead Webserver from GoAhead Software of Bellevue, Wash. GoAhead has made this open source server available on their Website in versions for Wind River VxWorks, Windows CE, Window 95/98/NT/2000, Lynx, Linux, QNX and eCOS.

Java

Dallas Semiconductor developed a small Java enabled embedded controller called TINI™(Tiny InterNet Interface). Now part of Maxim, Dallas's TINI is an 8051 derived microcontroller-based development platform that executes Java code for embedded Web servers. The platform includes a Java™ programmable runtime environment.

The TINI board includes 1 MB of SRAM, processor, Flash ROM containing the firmware, and an Ethernet controller with interface circuitry in a 72-pin SIMM form factor for less than $70 in single unit quantities.

Microchip

Microchip, a leader in small microcontrollers, is promoting its products for use on these new embedded network devices. Microchip offers a PICDEM.net™ Internet/Ethernet demonstration board with a PIC16F877 microcontroller and TCP/IP firmware for under $300.

The firmware used for the network interface was developed by Jeremy Bentham of Iosoft Ltd. based on his book TCP/IP Lean: Web Servers for Embedded Systems.

SitePlayer

Netmedia claims its SitePlayer is the world's smallest Ethernet Web server. At $25, it could also be the least expensive. Based on the ubiquitous 8051, the SitePlayer does a remarkable job of packaging. In approximately one square inch, SitePlayer includes a Web server, 10baseT Ethernet controller, flash Web page memory, graphical object processor and a serial device interface.

Netmedia recently announced its internal SitePlayer language, which executes programs within SitePlayer. This can eliminate the need for external processors for many applications. It also makes it much more capable when using SitePlayer to enhance an existing product.

Scenix

Ubicom Inc., formerly Scenix, commonly known for making super fast low-end Microchip PIC compatible processors, has recently announced its IP2022 processor. This processor implements a much more capable architecture than its predecessors and maintains its frantic clock speed. The IP2022 is tailored to networking and the embedded Ethernet.

ZILOG

Zilog, creator of the significant Z80, has introduced an enhanced processor called the eZ80, which is aimed at embedded Webservers and includes the software for Internet connectivity. Supporting the full range of TCP/IP stack and applications, the eZ80 and software tools are a capable and cost-effective solution. An evaluation kit is available.

Rabbit Semiconductor

Rabbit Semiconductor, a spin-off of Z-World, the value added integrator of Zilog processors, has recently added TCP/IP to its offering of Rabbit2000 processor based single board computers and modules. The Rabbit2000 processor is available with the Dynamic C development environment, the royalty-free TCP/IP stack with source and extensive library and example applications. Rabbit Semiconductor offers the processor itself, a series of processor core modules and a wide range of single board computers based on these. In addition, a complete range of development kits support development with each of these.

Tidal Engineering's eSBC488

Tidal Engineering offers the eSBC488, an Ethernet capable single board computer with serial and GPIB capabilities. This board and the available software tools are targeted at the OEM instrument designer tasked with developing a test and measurement device with IEEE 488 and Ethernet. This requirement is becoming more and more commonplace. With a 10BaseT Ethernet port, GPIB interface, four serial ports and optional plug-in analog and digital I/O modules, the eSBC488 supports instrument developers. With a full complement of TCP/IP protocols including HTTP, telnet, DHCP, ICMP, SMTP and others, along with tools that support IEEE488.2 and SCPI parsers, almost any instrument, translator or gateway device can be implemented.

Texas Instruments TCP/IP Stack

Texas Instruments (TI) is offering a TCP/IP stack for its latest high-performance TMS320C6000 Digital Signal Processor that is the powerhouse of the bunch. The power of this DSP from TI allows the network controller functionality to run as a task on the same C6000TM DSP as the TCP/IP stack and the application. This allows designers to eliminate the Ethernet controller IC that is commonly required with all the other TCP/IP products discussed previously. TI offers a TCP/IP Network Developer's Kit (NDK) based on the TMS320C6000TM that includes complete hardware and software tools for evaluation and development with TI's TCP/IP stack. Production use of the TCP/IP stack requires a license from TI.

The products discussed in this article are just a few of those available that one might consider using to jumpstart a project. From our experience as embedded engineers, the development of Internet enabled devices can be a big challenge that can produce big rewards and satisfaction.