Design of an Embedded Controller for Some Applications of an Automotives 387 • The Advanced High-performance Bus (AHB) • The Advanced System Bus (ASB) • The Advanced Peripheral Bus (APB). Fig. 4. Block Diagram of AMBA Bus Design of Proposed Automotive Embedded Controller Fig. 4. Automotive Embedded Controller Design of an Embedded Controller for Some Applications of an Automotives 389 Fig. 6. Flow diagram of functioning of weather data processor Digital Image Processor: This processor processes the digital images captured by video camera placed aside of driver seat. If this processor identifies dust on front window glass, it will communicate with wiper controller to switch on the wiper for short duration to clear the dust. This action can be understand by flow diagram shown in figure 7. Fig. 7. Flow diagram of Digital Image processor Wiper controller: This is a peripheral core, allotted the task of wiper motor controlling. This receives data from multiple masters, as shown in figure and accordingly control the wiper motor. Wiper motor will switch on in three different conditions. • By switching on the user wiper switch • As per communicated by Digital Image Processor (if there is dust on front window glass). In this wiper motor will switch on for short duration. • As per communicated by weather data processor. (if raining condition is identified) Input from Sensors Temp. Sensor Fo g sensor Precipitation sensor Check weather condition Rainin g conditio n Fo g conditio n To wiper controller To Fo g Controller Input from Camera Check dust on front window glass To wiper controller Yes No New Trends and Developments in Automotive System Engineering 390 Fig. 8. Flow diagram of wiper controlling application. 3.2 Air conditioning system Embedded Controller Weather Data Processor Temperature Sensor (inside) Signal Condi tionin g Multi chann el ADC Data Bus Battery controller Data Bus AC System A.C Switch A.C Control S h a r e d B u s Battery Voltage Sensor Signal Condi tionin g Multi chann el ADC Battery electrolyte Battery charger switch A.C flaps Fig. 9. An Embedded controller block diagram for Air conditioning system Air Conditioning systems deliver air to the vehicle interior to provide comfort to passengers. These controller typically have control several motors (for blower and flaps), based on different inputs (e.g., temperature). Figure 9 shows block diagram of an embedded controller. This controller consists of weather data processor and battery controller as master and Air conditioning system as slave. Weather Data Processor: It is a processor processing the data coming from the different sensors regarding temperature condition inside the vehicle. According to the data this processor will decides the hot condition in the vehicle and communicated to AC system (peripheral) for necessary action. Wiper controller User Switch Digital Image Processor Weather Data Processor Wiper Motor Design of an Embedded Controller for Some Applications of an Automotives 391 Battery Controller: This processor monitor the battery condition of vehicle and responsible to take necessary action. It will monitor the charging of battery, if battery get overcharge, it will stop charging and vice versa. It also monitors the lever of electrolyte in the battery and warns the driver accordingly by communicating to other inbuilt core related to driver monitor display. In case of low battery, this processor will communicate with air conditioning module to tern it off to save the battery. Figure 10 shows working flow of this processor. Fig. 10. Flow diagram of working of battery controller Air conditioning system: It is a peripheral core responsible to control all function of vehicle AC. It receives user switch input as well as other command from weather data processor and battery controller regarding the operating of AC. 3.3 Driver alert massage display In modern era, passenger safety and safe drive is one of the most hot issue in automotives. Safe driving also depends on the driver alertness regarding the surrounding conditions. For example if there is raining or fog condition, driver should get alert readings, and suggestion to reduce driving speed if speed extending the defined value. The system for this can be implemented as shown in figure 12. This consists of weather data processor & Dashboard display controller. Both core are having processing power are master core interfaced with AMBA shared bus architecture. Batter y Controller Battery Voltage Sensor Battery electrolyte sensor To AC system, to switch off AC. Switch of char g in g Overcharging Condition Low battery condition Inform to Driver monitor core Low level of electrolyte New Trends and Developments in Automotive System Engineering 392 Fig. 11. Working of AC control system Fig. 12. Embedded controller for driver alert massage display S p eed Speedometer, Tachometer, Indicator Display Driver Alert Displa y Weather Data Processor Preci p itation Sensor Signal Condit ioning Multi channe l ADC Data Bus S h a r e d B u s Dashboard Controller Data Bus Data Bus Fo g Sensor Temperature sensor Fuel Sensor Air Conditioning S y stem User Switch Battery controller Weather Controller A.C switch o n AC. fan Control AC flap control Design of an Embedded Controller for Some Applications of an Automotives 393 Weather Data processor is sensing the weather condition as explain in previous section. It is sharing the weather condition with dashboard controller. Dashboard controller: It is a processor processing data related to dashboard display. Mainly it is handling two displays. Dashboard display- This digital LCD displays speed, distance in Km, fuel level, indicator condition etc. Driver alert display- This display is use to display certain information to driver related to car. Example information of weather, car engine over temperature, any linkage in car, security issue in car, emergency massages propagated by road side base stations, massages of inter vehicular communication or particular sign detection by in-vehicular camera. This display will be placed just side to dash board display and easily seen by driver. In this application weather data processor will process the sensor data and decides the environment condition like raining condition or fog condition. The information will be communicated to dashboard controller to display on alert display. Also dashboard will see the speed of vehicle, if it found more speed it will display massage regarding lower down the speed of vehicle. 4. Conclusion The embedded system for an automotive control system can be effectively design by extracting the benefit of multicore SoC technology. An integrated automotive controller can be design by using homogeneous or heterogeneous multiple cores (processors) connected with the shared bus like AMBA. The architecture will give better result with efficient resource sharing like peripheral device and memory. 5. References AMBA Specifications (Rev 2.0), ARM Limited 1999. Andy Birnie,(2006). “Centre Body Control: A Finely Balanced Systems”, Freescale semiconductor Foroum, Peris, Andy Birnie (Oct. 2006, “Meeting the Low Power Challenge in Body Systems at Each Performance Level- from 8 to 32 bit”, Freescale semiconductor Foroum, Peris. ARM controller user’s manual David Geer( May 2005). “Chip maker turn to multicore Processor”, IEEE Conf. David Lopez (Oct.2006).“Intelligent Distributed Control (IDC) Small and Cost Efficient Local Intelligence Solutions”, Freescale semiconductor Foroum, Peris. Dimitris Nikolopoulos (2006), “Facing the Challenges of Multicore Processor Technologies using Autonomic System Software”, Proceedings of 20th IEEE International Parallel & Distributed Processing Symposium, P.Peti, R. Obermaisser (2005), “An Integrated Architecture for Future Car Generations”, Proceedings of the Eighth IEEE International Symposium on Object-Oriented Real-Time Distributed Computing (ISORC’2005) Roman Obermaisser et. al, (July 2009). “From a Federated to an Integrated Automotive Architecture”, IEEE Transaction on Computer-Aided Design Of Integrated Circuits And Systems, Vol. 28, No. 7. The LEON Processor User’s Manual New Trends and Developments in Automotive System Engineering 394 Thomas Beck (2001). “ Current trends in the design of automotive electronic systems”, Proceeding of Design, Automation, and Test in Europe Conference pp.0038, Y. Tanurhan, et. Al (1996), “A Rapid Prototyping Approach for Specification and Design of Distributed Automotive Control Systems”, IEEE Proceedings of EURWRTS. 20 Arbitration Schemes for Multiprocessor Shared Bus Dr. Preeti Bajaj and Dinesh Padole G.H. Raisoni College of Engineering, Nagpur India 1. Introduction Performance of Multicore Shared bus Embedded Controller depends on how effectively the sharing resources can be utilized. Common bus in System on Chip is one of the sharing resources, shared by the multiple master cores and also acting as a channel between master core and slave core (peripherals) or Memories. Arbiter is an authority to use the shared resource (Shared bus) effectively, so performance also depends on arbitration techniques. The arbitration mechanism is used to ensure that only one master has access to the bus at any one time. The arbiter performs this function by observing a number of different requests to use the bus. Master may request to bus master (arbiter) to use the bus during any cycle. The arbiter will sample the request on the rising of the clock and then use predefined algorithm to decide which master will be the next to gain access to the bus. On-chip communication architecture plays an important role in determining the overall performance of the System-on-Chip (SoC) design. In the recourse sharing mechanism of SoC, the communication architecture should be flexible to offer high performance over a wide range of data traffic. 2. Arbitration techniques. There are several arbitration techniques has been developed mention as below. 2.1 Static fixed priority algorithm Static fixed priority is a common scheduling mechanism on most common buses. In a static fixed priority scheduling policy, each master is assigned a fixed priority value. When several masters request simultaneously, the master with the highest priority will be granted. The advantage of this arbitration is its simple implement and small area cost. The static priority based architecture does not provide a means for controlling the fraction of communication bandwidth assigned to a component. If masters with high priority requests frequently, it will lead to the starvation of the ones with low priority. Advantages: It is simple in implement & Small area cost Disadvantages: In Heavy communication traffic, master that has low priority value can not get a grant signal. New Trends and Developments in Automotive System Engineering 396 2.2 TDM/Round-Robin algorithm Time division multiplexed (TDM) scheduling divides execution time on the bus into time slots and allocates the time slots to adapters requesting use of the bus. Each time slot can span several physical transactions on the bus. A request for use of the bus might require multiple slot times to perform all required transfers. However, in this architecture, the components are provided access to the communication channel in an interleaved manager, using a two level arbitration protocol. M1 N M2 M 3 M4 N N Y M1 M2 M2 M2 M3 M3 M3 M4 Arbitration time (Request check) Re q uest Ma p Old ( rr2 ) Round Robin TDMA new ( rr ) Fig. 1. Round Robin based arbiter communication architecture The first level of arbitration uses a timing wheel where each slot is statically reserved for a unique master. In a single rotation of the wheel, a master that has reserved more than one slot is potentially granted access to the channel multiple times. If the master interface associated with the current slot has an outstanding request, a single word transfer is granted, and the timing wheel is rotated by one slot. To alleviate the problem of wasted slots, a second level of arbitration is supported. The policy is to keep track of the last master interface to be granted access via the second level of arbitration, and issue a grant to the next requesting master in a round-robin fashion, at figure 1, the current slot is reserved for M1, but it has no data to communicate. The second level increments a round-robin pointer rr2 from its current position at M2 to the next outstanding request at M4. Advantages: Easy to implement Disadvantages: Leads to the mistake of data transfer However, these techniques are often inadequate. In the former, low priority components may suffer from starvation, while high priority components may have large latency. Low system performance because of bus distribution latency in a bus cycle time. Hence there is need to design some more efficient arbitration scheme. The chapter presents four arbitration schemes for system on chip communication as below. • Static Lottery Bus architecture • Dynamic lottery bus architecture • ATM switch architecture • Fuzzy Logic based arbiter [...]... capabilities during runtime Finally, we conclude the chapter in Section 7 414 New Trends and Developments in Automotive System Engineering 2 Self-adaptation in the context of automotive embedded systems Under the umbrella term self-adaptation a set of terms is defined, e.g self-x properties In this section we will explain relevant terms in the domain-specific context of automotive embedded systems Self-adaptive... driving situation Car manufacturers may specify distinct scenarios (e.g driving situations) in which defined functions of the automobile are necessary 420 New Trends and Developments in Automotive System Engineering Fig 2 Integration of SystemC validation on EAST-ADL layers of abstraction For the iterative validation of the design we use SystemC simulations SystemC is a standardized system modeling and. .. predefined scenarios may be a potential trade-off for automobiles To use the full potential of the previously described self-x properties in automotive embedded systems, certain challenges must be met In the next Section we will describe these challenges in detail 416 New Trends and Developments in Automotive System Engineering 3 Challenges in realizing self-x properties in automotive embedded systems... manage these systems from the outside 412 New Trends and Developments in Automotive System Engineering In recent years, a lot of research has been done, trying to explore new methods for the management of general complex software systems Within the research area of Selfadaptation (McKinley et al., 2004) and Self-organization (Serugendo et al., 2004) new paradigms for the management of complex systems have... interact with several in- vehicle domains, e.g the power-train and infotainment domain In future, the trend of establishing more and more interactions between software components will continue, e.g through x-by-wire features, where mechanical transmission is replaced by electrical signals This results in a growing interdependency of separated software domains and in an increased need for interconnection Another... the hardware platforms (Nodes) and the interconnecting LocalBus Components in the FDA are interconnected with FunctionConnectors and in the HDA 422 New Trends and Developments in Automotive System Engineering Fig 3 Composite diagram of the use case at Analysis Level with HardwareConnectors Additionally, LocalDeviceManagers exist for each depicted Sensor and Actuator in the Functional Design Architecture... boundaries are vague, and the transition from member to nonmember appears gradual rather than abrupt A fuzzy set can be defined mathematically by assigning to each possible individual in the universe of discourse a value representing its grade of membership in the fuzzy set This 404 New Trends and Developments in Automotive System Engineering grade corresponds to the degree to which that individual is similar... functionalities in the comfort domain (e.g new infotainment features) Most of these functionalities will be realized in software, which increases the amount and importance of software within the automotive domain necessarily But these new features will also increase the complexity of future vehicular system architectures For instance, driver assistance systems increase the complexity because they interact... and S Dey, (2001) System Level Performance analysis for designing on-chip communication architecture”, IEEE Trans Computer- Aided Des Integr Circuits Syst Vol 20 K Lahiri, A Raghunathan, G, Lakshminaray,(2001) “Lotterybus : A new high-performance communication architecture for system- on-chip designs” Proc Design Automation Conf pp 15-20 410 New Trends and Developments in Automotive System Engineering. .. guarantee and meet the safety requirements of automotive systems even in adaptive systems (for example the ability to satisfy hard timing constraints) This results in an implied limitation of possible configurations of the system The mandatory system constraints must be extracted during the design process and enforced during runtime Thereby, the reconfiguration process of the system must not influence . Of Integrated Circuits And Systems, Vol. 28, No. 7. The LEON Processor User’s Manual New Trends and Developments in Automotive System Engineering 394 Thomas Beck (2001). “ Current trends. of char g in g Overcharging Condition Low battery condition Inform to Driver monitor core Low level of electrolyte New Trends and Developments in Automotive System Engineering 392. chosen in a pseudo-random way, favoring components with larger numbers of tickets. The probability of granting component C i is given by New Trends and Developments in Automotive System Engineering