Computers Today, May 16-31, 1999, Tech Trends; The Cells of Intelligence

As sophisticated microchips enter application-specific environments, the line between embedded systems and PCs is fast blurring.

How many times have you wondered about the grey cells in your different household devices? How does your washing machine know whether the load is half or full? How does your microwave make smart "auto" grilling or warming functions? Why is your new refrigerator called "intelligent"? Welcome to the world of embedded chips-sophisticated microprocessors that aid a range of devices and machines to make smart decisions and run effectively.

Any mention of chips or microprocessors pops up the inevitable image of the traditional desktop computer having a monitor, hard disk and keyboard and a mouse. But try becoming more aware: chips and microprocessors are present all around us. Small chips are embedded inside traffic lights, microwaves, VCRs, talking dolls, camera, bank ATMs, security and medical devices. These chips do their specified tasks without repetitive instructions. For example, you don't need to stand next to a traffic light and punch buttons to change the signal from red to green-the embedded chip placed within the traffic lights automatically do that at regular time intervals as per the program.

Embedded chips come in many forms. The most basic type is a single chip which may be "embedded" with other chips in a hybrid system or application-specific integrated circuit (ASIC). Its input comes from a detector or sensor; its output goes to a switch for starting or stopping the operation of a machine.

Embedded PC Architecture

Today most high-performance embedded systems are based on PC technology. The key advantage of the PC platform approach is that embedded products can be developed faster and at a lower cost. Besides, developers and designers can enjoy the advantages of widely available PC-compatible hardware, software, peripherals and third-party development tools. It opens doors to innovative and functional hardware options that go way beyond desktop-style disk drives and pointing devices. For example, display technologies, touch sensors and speech recognition.

The minimum configuration needed to create a PC-compatible system is a processor, memory and board-level peripherals such as an 8254 timer, 8259 interrupt controller and an 8237 DMA controller. The embedded product can be tied to the PC platform via any bus protocols including ISA (industry standard architecture), PCI (peripheral components interconnect), and USB (the universal serial bus).

A major part of the total cost of designing an embedded application constitutes software development. Using software written for the PC platform is a less costly option than custom programming. Also, a PC can be used to develop the embedded software design, including build and debug tasks, in line with hardware development. This results in quicker time-to-market.

Embedded systems are written in a low-level language, usually Assembler. The object code is burned into the chips ROM memory to ensure that the code cannot be altered, except in specific cases where ROM needs to be updated.

Market research organisations like the Gartner Group. divide the embedded systems into three core categories: microcontrollers, microprocessors and large-scale systems. Microcontrollers cannot be programmed and most often do not have a real-time clock. They are usually found in small devices such as temperature sensors and smoke and gas detectors.

The microprocessors carry out the more sophisticated functions such as complex calculations and control sequences. They are mostly found in telephone exchanges, lifts, diagnostic devices, among others. It is estimated that about seven percent of the microprocessors will have transient Y2K bug problems while two percent may have "persistent" problems. Generally, an embedded microprocessor looks after a group of different microcontrollers.

The proliferation of embedded systems can be attributed to two key factors: convenience and cost. Smart microchips make devices and equipment more flexible, effective and secure. They take over mundane chores. Since these processors are inexpensive, it makes sense to boost their overall performance by dedicating them to do a specified job. Today, it is less expensive and easier to add new features to an embedded system. For example, earlier a robot's arm would have had a single chip: today it would have at least ten of them-one each for a specialised task such as elbow, fingers, and so on.

Time is the key in embedded systems. In most cases, the system has to accept and respond to inputs within a predictable period of time. A late answer is often a "wrong" answer. Take the case of aircraft flight controls-everything has to run in precision sequence-in nanoseconds. Most embedded system languages specify the maximum and minimum number of clock cycles an instruction will take to execute.

There are other soft spots too. The Y2K problem looms high on the list. Flaws in embedded systems are more difficult to find and check since they are spread out and they don't have easily readable systems. Examples of high-risk devices include advanced phone systems, fax machines, security systems, ATMs, card-readers etc. A common belief is that anything and everything that has a power cord or a battery is a candidate for the Y2K. It's not so (see check list). In most cases, if there is no way to display or update the date (even on a machine or device with an installed chip) then that product is unlikely to fail with a Y2K problem. That should be reason enough for embedded chip users to heave a hurrah of relief.

Anatomy of the Chip Power

The embedded chips work round the clock, all across the world and make our life easier, comfortable and secure. It is estimated that more than 90 percent of chips go into embedded systems. From retail to medical to telecom, embedded systems are used industrywide across different platforms.

Industrial computing is a key application area for embedded products. They provide the "grey cells" to the factory machines to read, monitor and control situations. For example, rugged PCs placed around factory floors which monitor floor activities and controllers on doors.

The telecom sector primarily uses embedded technology for routing communications. For example, when a call comes in, it is transmitted to a room where there's a box-like electronic device filled with different electronic cards, each of which have their own embedded chips. On receiving a call, the chips process the transmittal information, determine which phone line is free and send the communication accordingly.

Similarly in the retail industry, embedded chips provide the brain power and assist the smooth and accurate functioning of point of sale systems, electronic cash registers and handheld tracking devices. These chips not only maintain detailed inventory but also enable this critical data to be shared across different departments or geographically distributed offices via the network.

Embedded chips are being increasingly used in imaging and networking applications such as laser printers, modems and gaming devices. The processor takes information from your PC's CPU and communicates this data to the print head which then imprints the image directly on the paper. Even basic ink-jet printers today have embedded chips to tell the engine when to put the print head on paper and when to lift it. Likewise, chips within a router can receive data, determine where it needs to go next, and relay it to the requisite destination.