Background of Automotive Embedded Systems

Every year, automobile manufacturers worldwide pack new embedded system into their vehicles. Tiny processors under the hood and in the deep recesses of the car gather and exchange information to control, optimize, and monitor many of the functions that just a few years ago were purely mechanical. The technological advancements of embedded system and electronics within the vehicle are being driven by the challenge to make the vehicle safer, more energy efficient and networked. Flash-based microcontrollers, from on-chip system to FPGA, are the command center for embedded system design.

In 1968, the Volkswagen 1600 used a microprocessor in its fuel injection system, launching the first embedded system in the automotive industry. Historically, low-cost 8 and 16-bit processors were the norm in automotive controllers, and software engineers developed most of the code in assembly language. However, today's shorter development schedules and increased software complexity have forced designers to resort to select the more advanced CPUs and a higher level language in which designers can easily reuse modules from project to project. A successful automotive-electronic design depends on careful processor selection. Modern power train controllers for the engine and transmission generally require 32-bit CPUs to process the real-time algorithms. Other areas of the automobile, such as safety, chassis, and body systems, use both 16-bit and 32-bit processors, depending on control complexity. Although some critical timing situations still use assembly language, the software trend in automotive embedded systems is toward C. The control software is more complicated and precise for the current vehicles.

Advanced usage of embedded system and electronics within the vehicle can aid in controlling the amount of pollution being generated and increasing the ability to provide systems’ monitoring and diagnostic capabilities without sacrificing safety/security features that consumers demand. The electronic content within the vehicle continues to grow and more systems become intelligent through the addition of microcontroller based electronics. A typical vehicle today contains an average of 25-35 microcontrollers with some luxury vehicles containing up to 70 microcontrollers per vehicle. Flash-based microcontrollers are continuing to replace relays, switches, and traditional mechanical functions with higher-reliability components while eliminating the cost and weight of copper wire.

Embedded controllers also drive motors to operate power seats, windows, and mirrors. Driver-information processors display or announce navigation and traffic information along with vehicle diagnostics. Embedded controllers are even keeping track of your driving habits. In addition, enormous activity occurs in the entertainment and mobile-computing areas. Networks are a recent addition to embedded controllers which are the challenge of squeezing in the hardware and code for in-car networking. To satisfy new government emissions regulations, vehicle manufacturers and the Society of Automotive Engineers (SAE) developed J1850, a specialized automotive-network protocol. Although J1850 is now standard on US automobiles, European manufacturers support the Controller-Area Network (CAN). High-bandwidth, real-time control applications like power train, airbags, and braking need the 1Mbps speed of CAN and their safety critical nature requires the associated cost. Local Interconnect Network (LIN) typically is a sub-bus network that is localized within the vehicle and has a substantially lower implementation cost when compared to a CAN network. It serves low-speed, low-bandwidth applications like mirror controls, seat controls, fan controls, environmental controls, and position sensors. Embedded system in the automotive shares the general characters of common embedded system, but it has its own primary design goals of automotive industry. Reliability and cost may be the toughest design goal to achieve because of the rugged environment of the automobile. The circuitry must survive nearby high-voltage Electronic Magnetic Interference (EMI), temperature extremes from the weather and the heat of the engine, and severe shock from bad roads and occasional collisions. The Electronic Control Units (ECUs) should be developed and tested on the all kinds of situations with low cost. Although testing time grows with the complexity of the system, a reliable controller also requires complete software testing to verify every state and path. A single bug that slips through testing may force a very expensive recall to update the software. Therefore the development of high-ability tools is also active in the field of automotive embedded system.