Challenges brought by the hottest automotive elect

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Automotive electronics: multi-core processors bring various challenges

dual core CPU has made rapid application in automotive electronics system, and the system software and hardware, power consumption and heat dissipation also need to be changed accordingly

most microcontrollers used in today's automobiles basically adopt the traditional single core structure, but promote industrial upgrading; The dual core processor, which has been widely used in the computer industry, will also develop rapidly in the automotive industry and will soon become a standard configuration. The power system and safety system have taken the lead in adopting dual core processors, and other systems have gradually begun to change their architectures

"multicore is actually a new generation of product design standard for power train," said Kent Helfrich, director of electronic integration and software of general motors. "In the past decade, we have carried out some multi-core designs in the engine control module, and now we are integrating these designs into one chip."

however, the application of multi-core processors in some systems such as infotainment systems is still limited, but it is expected to achieve rapid growth in the next few years. Chipmakers expect big changes in their product mix

Freescale dual core processors used in safety and power systems are often used to synchronize redundant tasks of the system

"we expect that by 2015, the market capacity of multi-core processors will be quite large, accounting for about half of our shipments," said Amrit vivekanand, marketing manager of automotive business unit of renesastechnology America Inc

like most electronic designs, software is the biggest challenge faced by electronic control designers. To realize the speed of dual core processors, it is necessary to clearly distinguish the tasks of single core and dual core processors

most chip manufacturers say that the speed of dual core processors is about 1.7 times that of single core processors. However, because memory access and other problems will slightly affect the speed of dual core processors, the clock speeds of the two processors are very similar. However, programs with poor segmentation also affect the performance of the processor

"if the program segmentation is not done well, it is difficult for you to enjoy the performance advantages and achieve the performance improvement goal," said julienfabregues, marketing manager of automotive microcontroller of STMicroelectronics

the increase in demand for infotainment system will increase the multi-core shipment of Renesas technology by 50% by 2015

in the field of automotive applications, vehicle manufacturers and primary suppliers do segment coding by themselves, rather than relying on operating systems or other software tools. This is especially important for some systems, such as power systems and safety systems, because the commands in these systems must be started accurately when required

"now, we have to assign part of the code to the 0 processor and the other part to the 1 kernel. There is a conversion problem," Helfrich said. The proportion of exports to emerging countries will also be greatly increased. Technical staff Michael Grimes pointed out that this method (called static distribution) has formed a fixed model. "The operating system in the computer field adopts a dynamic allocation method, and the system decides which kernel to use to run the code," he said. "We decided to make the 0 core as an extrusion technology company by ourselves, and especially demonstrated the extrusion drive concept that can freely choose the electromechanical situation, and what the 1 core can do."

hardware changes

although software may be the key problem of multi-core processors, it does not mean that the work of hardware engineers is simple. Just upgrade it. When two processors exist on a silicon chip at the same time, the characteristics of power consumption, clock speed and electromagnetic interference are completely different

storage issues are equally important. Silicon chip space is basically used for storage and processor work. Flash memory generally takes up half of the space, while adding a processor core takes up only 5%, Grimes said

in order to improve the efficiency of flash memory, designers must adopt a system allocation scheme that can ensure that each kernel can read data when needed - and these data must be up-to-date. This is the time for storage management

"in terms of storage, you need an intelligent storage controller and an intelligent read ahead cache," fabregues said

safety system components such as airbags will drive the growth of STMicroelectronics business

on the other hand, engineers also need to figure out what they want to do through the second core. In some applications, such as infotainment, the kernel is responsible for different tasks. However, in the power train and safety system, many processors execute the same program to provide fault tolerance

"in many security applications, processors run sequentially, which is the most effective way to meet the iso26262 standard," fabregues said

the chip specially designed for this application must have a unique logical relationship, and the results of each processor can be compared. "The chip should be specially designed for the lock step operation, and the logical relationship is responsible for the comparison of results, so that errors can be quickly identified," said ray Cornyn, director of automotive microcontrollers at Freescale Semiconductors

energy consumption and heat

the challenge of heat and energy management will not disappear with the adoption of dual core processors. These problems are actually the driving factors for the application of dual core processors. However, the improvement of clock speed also leads to the increase of energy consumption and system temperature

the low clock speed of dual core chips performs well in the power train. The lower clock speed also gives dual core chips an advantage over single core chips. "The operating temperature of the power system is very high, and the chip certainly does not run as fast as it does at room temperature," Grimes said

in other systems on the vehicle, engineers are more concerned about the reduction of the number of electronic control boxes. In the case of many vehicles with a large number of controllers, a slight reduction in the demand for each module can save a lot of energy consumption

"energy consumption will become a big problem, especially for electric vehicles," said chriswunderlich, automotive system application engineer of infineontechnologies. "You can turn off a processor in order to reduce energy consumption, and you can also start it to improve processing performance when you need the investment later to raise a total of 28.56 million pounds."

wunderlich also said that in the transmission system, every shift involves many actions. An additional processor can be turned on when needed to handle these tasks, and turned off before the next shift to save energy

the increase of electronic components has also brought other problems, such as electromagnetic coupling. EMC will affect the operation of chips on the vehicle and the consumer electronics connected to the vehicle, so a lower clock speed can bring many benefits

Ken Helfrich of General Motors said that software is the main problem in the process of engine system changing to dual core processor architecture

(such as ECOTEC Di turbine engine in 2010)

"if you increase the processor frequency from 200MHz to 400MHz in order to improve the system performance, the increase of electromagnetic radiation is very obvious - several orders of magnitude more than a single EMC," vivekanand said. He pointed out that in some applications, such as entertainment information systems, dual core processors can enable engineers to double the clock speed, but the energy consumption has not increased so much, so it will not increase too much energy consumption

although dual core processors will still be the mainstream architecture in the computer market in the next few years, automotive engineers have begun to plan to adopt more processors in the automotive field. Of course, multi-core processors with higher performance may not be applied to automobiles in the next few years, but some companies have begun to carry out relevant R & D projects and seek cooperation

"about a year and a half ago, we started discussing with Continental to develop three core processors for automotive braking and chassis systems," Cornyn said

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