A new generation of microcontrollers: The RH850 Family of 40-nm MCUs for better, safer motor vehicles – part 2
In this Part-2 Technology Special story, Hiroaki Kaneko, General Manager of the Automotive Systems Division in Renesas Electronics’ Marketing Unit, highlights the high-performance 32-bit MCUs in the RH850 family, the top end of our newest products. He points out that these advanced chips exhibit enormous application potential for automotive ECUs (electronic control units) and describes their important design features and benefits.
Anticipating twice as many automotive MCUs per vehicle (2018 vs. 2010)
Worldwide automotive sales volume is likely to continue growing at 4 to 5% per year, with estimated sales reaching 80 million vehicles in 2013. Rising demand in China, India, and other emerging-market economies is largely responsible for this ongoing growth. China, in particular, is expected to exhibit a very robust market expansion over the next three years. In 2009 China was already second only to the United States in annual sales volume, at over 10 million vehicles, and Renesas expects that volume to double by 2015.
The impact of semiconductors on the automotive industry is an amazing, yet relatively recent phenomenon. Just a few decades ago, cars did not come with embedded MCUs, or even with semiconductors. In the early 1970s, for example, you could find semiconductors in car radios, but not in any of the vehicle’s three basic systems—driving, turning, and stopping. Back then, chips were used only to add value to extra features.
Today though, MCUs are pervasive, critically important components in cars and trucks. They are hidden from view in all of a vehicle’s essential systems. The low emissions, good performance and excellent drivability achieved by modern engines, for instance, is made possible almost entirely by the monitoring, processing and real-time control capabilities of MCU-based electronic modules (ECUs, electronic control units).
Clearly, the availability of more optimized, better performing ICs and other semiconductor chips is the major factor pushing automotive technology today. For that reason, going forward Renesas expects to see a 10% annual increase in the volume of semiconductor devices used in new vehicles, outpacing the unit growth in car and truck sales. In fact, we believe that by 2018 the number of MCUs used in automotive systems will reach double what it was 2010 (see Figure 1).
Figure 1: Projected worldwide sales of automotive MCUs (by volume). By 2018, demand for these vitally important embedded control chips is expected to rise to double what it was in 2010.
Implementing capabilities and features that car buyers want
The major factors car buyers consider when choosing a new automobile traditionally could be broadly grouped into three categories: environmental, safety, and comfort. Recently, though, surveys have identified the emergence of a fourth category that has become quite important: connectivity.
In the environmental category, markets are seeking ways to reduce the greenhouse gases that cars and trucks produce. Microcontrollers play a central role in improving fuel efficiency, which lowers tailpipe emissions. Together with power devices, and other semiconductors, MCUs are vital solutions for improving a motor vehicle’s environmental profile.
In the area of safety, demand is rising around the world for functions that can reduce the incidence and severity of motor vehicle accidents. Studies show that most accidents are caused by driver inattention or by inappropriate situational responses. High-performance MCUs are increasingly being applied to reduce and mitigate the effects of human error. Blind-spot monitoring systems and collision avoidance systems are but two examples of popular new-car features that make vehicles safer.
Another consistently strong requirement among car and truck buyers is for features that deliver greater comfort for drivers and passengers—especially those that improve the driving experience, reduce fatigue and increase the perception of quality in audio systems and other amenities. Automotive MCUs already provide a wide range of advanced added-value features in the comfort area and can enable new innovations. For example, it’s possible for electronic systems to identify automatically drivers and passengers as they enter the vehicle and then perform personalization functions such as adjusting the interior lighting to preferred levels and also making specifically tailored adjustments to seat positions, HVAC settings, control panel layouts, steering and chassis control systems, etc.
The incorporation of MCU-based connectively in automobiles is a strong trend due to the rapid evolution and adoption of wireless technology and associated services. New-vehicle buyers are making it a very important decision factor for their purchases. They want a car or truck that can communicate with smartphones, deliver real-time traffic information, and provide high-quality GPS navigation assistance. Many purchasers are also looking for features that deliver intelligent driver support by monitoring and responding to traffic and road conditions.
Earning the biggest share of the global automotive MCU market
Renesas has a track record of winning—by a significant margin—the leading share of the worldwide market for the MCUs used in car and truck applications. According to data from a leading market research firm(*1), for instance, Renesas captured a 42% share of this global market in 2011, demonstrating a broad preference among automotive engineers for the solutions in our extensive MCU portfolio.
Now we are striving to boost our automotive MCU market share up to at least 50% in the near future. This is a significant challenge for us, one that entails the introduction of new chips offering major new opportunities and benefits for designers of in-vehicle systems. We are making good progress in this regard.
As our global sales numbers imply, Renesas microcontrollers are being incorporated into multiple functions in most new cars. Our high-end 32-bit MCUs, for example, are found in powertrains, chassis components, vehicle bodies, safety features, and instrument clusters. Further, our versatile 16-bit MCUs are essential components for controlling numerous sensors, switches, and other system components.
Figure 2 highlights two product lines we highly recommend for new designs for automotive electronics. The RL78 family contains excellent choices for functions that can be handled by 16-bit processors, while the RH850 family offers the best solutions for automotive applications that require more electronic ‘horsepower’.
Figure 2: Renesas automotive MCUs recommended for new designs. No matter what in-vehicle function has to be controlled, there is a chip in either the high-end 32-bit RH850 product group or the ultra-low-power 16-bit RL78 product group that is optimum for the task.
Developing the RH850—a new generation of top-end 32-bit MCUs
To meet the ambitious goal of raising our leadership automotive MCU market share above 50%, Renesas management asked our R&D experts to produce a new portfolio of system design solutions that meet or exceed the design requirements of current and future in-vehicle functions. Large, empowered teams of chip, process and system engineers have been aggressively addressing all aspects of this MCU technology challenge. Their success is clearly evidenced by the flash MCUs in the RH850 family—high-performance, power-efficient devices built with our 40-nm semiconductor technology. These advanced 32-bit chips aim at vehicle ECU applications.
The products within the RH850 family play a very important role in our MCU growth strategy. These advanced automotive solutions synergize the proven strengths of our V850 and SuperH architectures—offering the best of both, plus more speed, processing capabilities and functionality. Their key features, which are summarized in Figure 3 and described in more detail below, give vehicle engineers important design advantages. We firmly believe that RH850 MCUs are destined to become the top-performing MCU product line for customers building and applying ECUs in cars and trucks for world markets.
Figure 3: Key features of 40-nm RH850 microcontrollers. The many different devices in this new 32-bit product line deliver the performance and capabilities needed for handling today’s automotive ECU applications, as well as those anticipated in the future.
RH850 MCUs consume very low power relative to the high level of performance they deliver. The 40-nm chips use about 26% less power than an equivalent 90-nm device. Such impressive power savings are extremely beneficial for ECUs because they help to resolve packaging and environmental issues that currently mandate design tradeoffs that sacrifice application potential.
Specifically, automotive ECUs have to be compact so they can be mounted in open places in a car’s body. Yet they must be big enough to be able to dissipate internally generated heat. By saving power, an RH850 MCU enables customers to produce smaller, more capable ECUs that can fit into tighter spaces.
ECUs also have to be able to operate continuously in the high temperatures reached when a vehicle is running, especially on very hot days. Renesas addresses this issue by guaranteeing that RH850 MCUs will function at ambient temperatures(*2) up to 125º C (257º F), and at junction temperatures(*3) up to 160º C (320º F). System engineers can therefore be confident when mounting these new high-end devices into ECUs close to heat sources in engine compartments and elsewhere.
Using a multicore design to ensure functional safety
In recent years, functional safety specifications have become an essential part of car and truck performance profiles. These specs are intended to ensure that the electronics controlling essential functions such as steering and braking will always detect and respond to system failures in ways that maintain the safety of the vehicle’s occupants. In particular, functional safety implementations must conform to international standards IEC-61508 and ISO-26262, which describe requirements for fail-safe protection methods.
Renesas is very knowledgeable about the subject of functional safety, having been involved from the beginning in the drafting of the IEC-61508 standards. For over ten years our technology experts have been acquiring a deep understanding of successful safety concepts and implementations. Their accomplishments in this area are the best in the industry, and our accumulated expertise is the foundation of critically important RH850 capabilities.
These new 32-bit MCUs combine a high-performance multicore CPU with low-power technology to deliver functional safety together with fast calculations and good input/output control. Moreover, our chip designers are able to optimize the functional safety core, high-speed arithmetic core, and input/output core of various RH850 models for specific automotive control system applications and goals. Chips can be configured to provide an application’s required level of performance while consuming the smallest possible amount of power.
Performance levels for RH850 MCUs extend to cores that run as fast as 320 MHz. The functional-safety core uses a proven dual-core lockstep(*4) design that achieves fast, reliable error detection at low power.
Offering MCUs covering the full span of ECU requirements
All of the eight MCU series in the RH850 product group are tailored for high-end automotive ECUs; they are differentiated by optimizations for specific types of control functions and applications (see Figure 4). Devices in the C, D, E, F, P, R, S, and V series meet the specific needs of all of the various in-vehicle functions: powertrains, NVH (noise, vibration and harshness) systems, instrument clusters, bodies, safety features, ADASs (advanced driver assistance systems), and more. The span of MCU models encompasses chips with single or multiple CPU cores and scalable functional IP blocks, memory and pin counts.
Figure 4: The RH850 family of next-generation 32-bit MCUs. Each of the eight device series—C, D, E, F, P, R, S, and V—contains chips with sets of performance characteristics and built-in functions optimized for specific ECU control tasks. Now system-engineering teams can learn and write all necessary programs for a single architecture, saving development time and sharing code to obtain the maximum return on R&D investments.
The different RH850 MCU series combine to meet the diversity of system design requirements of applications found in both advanced and emerging economies. Also, the various sets of features and performance levels provided by the broad span of Renesas products lets automotive engineers cost-effectively select the characteristics and capabilities needed to produce all types and models of automobiles within a brand, from luxury vehicles to economy ones.
Because system engineers who specify RH850 MCUs can create solutions for entire ranges of vehicle control applications, they gain major benefits by using chips with the same basic architecture. Especially, they can reuse code and hardware to obtain time and cost savings and maximize their returns on engineering investments.
Making it easier to develop control software
Additionally, MCUs in the RH850 product group accelerate software development projects by providing a consistent platform for all control-related applications. Until recently, automotive ECU platforms tended to vary, depending on the vehicle type and application. As a result, separate software development programs were required for each platform. Today, though, system designers are beginning to reject this approach because it creates significant inefficiencies, adding extra engineering and testing costs and causing unnecessary schedule delays.
Renesas helps customers reduce their software development workloads, shorten design cycles and cut expenses by offering a single architecture for all types of automotive ECUs. Only one IDE (integrated development environment) is needed to support the entire RH850 family of MCUs, and this software tool enables a smooth migration path from legacy designs to advanced automotive products.
Providing strong AUTOSAR support
In particular, Renesas is a strong supporter of AUTOSAR, the Automotive Open System Architecture. Companies in the European ECU industry are rapidly adopting this open platform because it simplifies and speeds up software development. Renesas joined the AUTOSAR consortium as a premium member in July 2004. Since then our experts have actively participated in efforts to standardize software platforms and the associated software design and test processes.
The AUTOSAR architecture provides a hardware abstraction level that hides hardware differences. Thus it allows vehicle and electronics manufacturers to take a component-based programming approach to application development. The resulting components can be ported and reused throughout the automotive industry. As a result, use of this architecture is expected to greatly improve the efficiency of software development for all companies that adopt it.
Software for AUTOSAR implementations includes a device driver—MCAL (Microcontroller Abstraction Layer)—that hides differences between the MCUs in various ECUs from higher system layers. Renesas has facilitated the adoption of this design methodology by including MCAL with our automotive MCUs since 2007. The new RH850 chips incorporate an MCAL conforming to the latest AUTOSAR version: AUTOSAR 4.0.
The strategy of providing both a single MCU platform and an industry-standard software platform allows Renesas to ease customers’ software development burdens.
Eliminating constraints caused by memory limitations
The limited size of a typical microcontroller’s internal flash memory has often been a vexing constraint for software developers. Unless the engineers could restrict code size to fit within an MCU’s relatively small storage space, they were forced to make difficult fixes or accept design compromises. The 40-nm fabrication process used for RH850 chips helps eliminate this type of system design challenge, though, by allowing up to 8 MB of internal flash—a generous amount for code and data. Moreover, blocks of data flash are included that emulate EEPROM functionality for reliable long-term storage.
By selecting an RH850 chip, software developers needn’t constantly worry about low memory limits. The device’s expansive on-chip flash might well make it possible to reintegrate applications that previously had to be broken up and run on multiple MCUs. additionally, the extra memory space the MCU provides facilitates the addition of functions and features previously precluded by low memory limits.
Ultimately, the larger memory size available in RH850 MCUs should enable more sophisticated ECU control programs that achieve higher levels of functional safety for cars and trucks, while also accelerating the development of new operational, comfort and connectivity features and capabilities. The resulting advanced ECUs will open the way to the next generation of motor vehicles.
Maintaining a technology edge beneficial to the global automotive industry
In continuing our technology and market leadership in automotive applications, Renesas has developed 40-nm, 32-bit RH850 MCUs chips that anticipate the emerging needs of automotive ECU applications for global markets. These new high-end MCUs, along with our 16-bit RL78 devices, hold great promise for enabling and enhancing in-vehicle electronic control systems now and long into the future. Automotive engineers who specify our products can take advantage of key features and benefits to gain sales advantages in fiercely competitive world markets.
Footnotes:
(*1) Source: The IHS iSuppli ‘Competitive Landscaping Too
(*2) Ambient temperatures: A term that refers to the temperature in a localized environment; i.e., in a room, inside a vehicle, in a car’s engine compartment, etc.
(*3) Junction temperatures: The internal, on-chip temperatures of a semiconductor device
(*4) Dual-core lockstep operation: Two independent CPU cores on an MCU chip execute the same operations, the results of which are compared to determine whether or not an error has occurred. If it has, fail-safe routines are implemented to protect the occupants of the vehicle.
About the author: Hideto Hidaka is General Manager, Embedded Memory Core Development Division of Renesas Electronics’ Technology Development Division.
To read the first part of this two-part article click here.
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