Understanding Smart Sensors - Nomads.usp

Communications for Smart Sensors 145entertainment products. In addition, intelligent transportation system (ITS)efforts to improve the efficiency and safety of surface transportation will requirenew technology in several consumer-oriented products to achieve their objectives.However, auto manufacturers are concerned that the reliability and functionalityof existing systems may be compromised by the addition of hardwareand software that they did not develop or qualify for use in vehicles. As a result,the SAE has developed the ITS databus (IDB) standard. The IDB really acts asa firewall, controlling and limiting the flow of information between the twonetworks to only that information that is valuable to both. The ITS databusapproach uses a gateway MCU to interface a network of consumer electronicscomponents and systems with existing vehicle systems as shown inFigure 6.15 [28].6.9.4 The Protocol as a ModuleThe protocol can be easily reconfigured into a new MCU design using themodular design methodology described in Chapter 5. In addition to the CPUand other modules, serial communications protocols, including CAN, both versionsof SAE J1850, SPI, SCI, and I 2 C can be treated as a modular peripheral.CellCellphonePhoneE-callE-callControllercontrollerGPS GPSreceiverReceiverPagerPagerGatewayGatewaycontrollerControllerMessage flowgateway controller(OEM)Steering buttonsSteering buttonsIn-dash displayIn-dash displayDoor/locksDoor/locksAudioAudioiDENiDENSensorsSensors(Other)(Other)ITS data busExisting busFigure 6.15 The IDB, which isolates consumer-added products from the manufacturerinstalledsystems in the vehicle.