On the engineering community website Element 14, a keyword search on “microcontrollers” and “automotive” generated over 80 results by way of application notes, design tips, product information, etc. It’s not hard to understand why there’s interest among electronic design engineers around the globe for this topic.
In recent years, advanced silicon processing has paved the way for the rapid development of electronics that enhanced and simplify our lifestyle. To illustrate further, recent development shows that there is a change of paradigm from the basic fuel enabled automotives towards a hybrid and fully electric vehicles with the debut of FlexRay technology in 2007 that provides high-speed communications bandwidth (up to 10 times the speed of existing communications protocols for automotive networks) required by today's active driving systems and tomorrow's autonomous cars with drive-by-wire capabilities. In general, FlexRay is a real-time communications system combining a static and a dynamic part. It is based on an extended TDMA (time-division multiple access) media access strategy.
The high speed networking communication protocol has enabled many new features that greatly elevated both safety and comfort and which required more complex and high capacity quantitative enabled microcontroller with a large embedded software capability. Thus, there is a substantial demand for more sensitive, robust and advanced electronics chips for the automotives power train (e.g. steering and brakes), chassis, infotainment (e.g. GPS, entertainment, Instrumentation), environment (e.g. LED lighting), safety (e.g. airbags) as well as the comfort of the driver.
In order to attain that, electronics chip makers have been working on innovative ways to create different range of microcontrollers that provide high speed communication, low power, large memory and even small footprints featuring 8-bit, 16-bit and 32-bit microcontrollers (MCU). In this article, three brands of microcontroller chipmakers discussed are Freescale, Microchip and STMicroelectronics.
Freescale has been actively driving the FlexRay within the FlexRay Consortium since 2000. Freescale is the first semiconductor company to introduce to the automotive market a FlexRay controller based on a 16-bit architecture. Currently, Freescale has a couple of 32 bit MCU running on Power Architecture. The company’s latest technology includes the MPC5674F that is running at 264MHz with Dual-channel FlexRay controller that is meant to provide for green power trained application by enabling precise control of engine events, such as combustion, without sacrificing performance while outpaces all powertrain MCU.
On the other hand, STMicroelectronics, also one of the leaders in the MCU for automotive, also provide four types of 32-bit MCUs embedded with an e200-core 32-bit Power Architecture with an application-optimized peripheral set and huge embedded Flash memory, to increase the ease of integration, maximize design reuse, shorten time to market, and reduce costs. All of the company’s new families of automotive MCUs are designed to support the latest automotive standards, including the AUTOSAR (AUTomotive Open System ARchitecture) open-systems architecture and FlexRay high-performance vehicle networking. To complement with the many applications available in an automotive electric systems, there is a planned memory ranging from 128kB to 4MB of Flash from the company’s four families of 32-bit MCUs.
Another leader in the automotive MCU market is Microchip, which provides low cost embedded solutions from their PIC32 family. Microchip’s PIC32 has the integrated USB 2.0 On-The-Go (OTG) functionality that helps the designer to solve for growing requirements of advanced USB OTG connectivity. Furthermore, PIC32 brings more convenience for the designers by having pin, peripheral and software compatibility with Microchip’s 16-bit MCU and DSC (digital signal controller) families. Most importantly, Microchip provides a common IDE platform for all their MCUs.
Moving on from 32 bit to 16 bit MCU, Freescale also provides FlexRay technology in its 16-bit MCU S12X family so as to broaden the choice of FlexRay solutions for automotive system engineers. STMicroelectronics has its own unique 16 bit MCU, the ST10 family, which comes with a DSP unit integrated with 40-bit wide MAC (Multiplier–Accumulators). In addition, the ST10 combines high CPU performance with high peripheral functionality and enhanced I/O (Input/Output) capabilities but with only two integrated CAN (Controlled Area Network) modules.
Comparatively, Microchip’s DSC from the dsPIC30F family has a system-on-a-chip (SoC) architecture that seamlessly combines the control features of a 16-bit MCU with extensive DSP functionality. In addition, Microchip also has its own low power RISC-based architecture that is based on its nanoWatt XLP (eXtreme Low Power Technology).
Now, let’s look at the low cost implementation of automotive systems using 8-bit MCUs. Freescale has a large scale of 8-bit MCU portfolio from its S08 family, which provides extended range of peripherals from USB (Universal Serial Bus) to LIN and 8-bit MCU solutions to support 5V operation.
For its part, STMicroelectronics’ 8-bit family of MCU consists of the ST6, ST7, ST9 and the latest STM8A. The STM8A devices are particularly suited for applications requiring non-volatile data storage that integrated true data EEPROM features state-of-the-art endurance and data retention.
Microchip, said to be the leader in 8-bit MCUs, provides more reasons for designers to look into these devices, wherein the company brings USB, LCD, CAN, Ethernet, and Capacitive Touch sensing to the segment.
Depending on the application needs, cost of implementation, power demands and the sophistication of the application, designers can select the most basic 8-bit MCUs to the most comprehensive 32-bit MCUs from these makers, wherein they can make the best out of the offered features such as FlexRay communication, low power technology) and high performance MAC in the DSP.
