Tuesday, 25 October 2011

Computers and Cars


Computers and Cars


Your car has as many as 100 microprocessors onboard. If someone said that to you would you believe them? Well it's true. Would you believe me if I said your car may contain more lines of software code than a fighter jet? Well it's true. Premium-class automobiles these days have somewhere in the neighborhood of 100 million lines of codes, about 95 million lines of software code more than a U.S. military fighter jet.
Lines of software code are necessary to operate 50 to 100 microprocessors known as ECUs (Electronic Control Units) onboard vehicles. Somewhere in the future automobiles are expected to use 200 million to 300 million lines of code to operate ECUs. This enables ECUs to make decisions in 15 to 40 milliseconds. It is estimated that more than 80 percent of car innovations come from computer systems and that software has become the major contributor of value (as well as sticker price) in cars. Over the years the number of microprocessors has increased to meet emissions, fuel economy standards, reduction of wiring, and meet new safety features. In the future there is even a possibility of connecting your car computer system to a network specialist that can download data, analyze data, and upload needed software.
Microcontrollers (MCUs) located in the automobiles engine control system are small computers containing a core processor, RAM (random access memory), and input/output peripherals. These microcontrollers have gone from 12 MHz 8051 CPU's to 32-bit processing power with multiple sets of peripherals. Microcontrollers are used to control the transmission, anti-lock brakes, air bag system, climate controls, and other key components within a car. Multiple microcontrollers work alone and need to send information to other MCUs. As a result, three different network bus systems were developed named CAN, LIN, and MOST.
CAN (Controller Area Networks) is a fast serial bus used in automobile applications. CAN uses twisted pair cable to allow ECU's and other devices to communicate with one another without a host computer (server). Data can be sent up to eight bytes using non-return-to-zero binary pattern bit rates, up to 1 Mbps- the same speed as some satellite downloads.
LIN (Local Interconnect Network) is a low-speed communication bus with one master and up to 16 slave buses. LIN uses sub-networks in order to communicate with CAN up to 20 kbps.
MOST (Media Oriented System Transport) is a high speed multimedia network used to transmit video, audio, and data in automobiles. The network uses a ring topology with synchronous communication. MOST is broken down into three generations. MOST25 was first introduced which only had a bandwidth of 705.6 kbit/s. Second, MOST50 increased bandwidth and was capable of transmitting data up to 1024 kbit/s. MOST150 was released in 2007 and increased data transfer rates up to 3072 kbit/s.
All in all, cars these days are becoming more sophisticated than ever before. Computer technology has taken a major toll on how automobiles are manufactured today. Cars now are not all about the rims, paint job, and sunroofs like they have been in the past. Consumers want GPS, satellite television, heat sensing cameras, and more; so software and hardware equipment has been on the rise by many automobile manufacturers. Who knows where this technology will take us, there may come a day that all we do is press a button to start the car; lean back, and let the car take over duties like accelerate, steer, and stop. Given the amount of code lines projected to be in automobiles in the next few years this day is not far away.
Written by DeVry University student studying Network Management & Communication.
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