Have you ever been curious about how a car’s ECU works? If so, you’re in the right place.
The modern cars come with multiple ECUs connected to the CAN bus—the car’s internal computer network. ECUs control almost every part of a car, like an engine, brakes, transmission, and airbags, while automating these parts and increasing efficiency.
ECUs consist of one or more microcontroller CPUs that are specialized chips adapting easily in a rugged operational environment, high temperature, and gravitational pull.
STMicroelectronics produces a series of 32-bit microcontrollers (MCUs) for automotive ECU applications. These chips come with embedded flash memory that ranges from 128 KB to up to 10 MB.
The SPC5 family of ECU chips also offers various processing capabilities, depending on the automotive applications, like general-purpose, secure and connected, and high performance. You’ll find CPU clock speed as low as 48MHz and up to 200MHz.
Therefore, depending on the programming code length or numbers, the car manufacturer can choose different chips for the ECUs.
SPC5 MCUs come with up to three processing cores. You will mostly find these in ECUs that control the engine and chassis, plus advanced driver-assistance systems (ADAS), driver safety, and windows and doors.
The chip and its memory module can withstand up to 165 °C temperature and works fine even at -40 °C. Since these are automotive-grade CPUs, they can also endure heavy shocks.
ECUs made from these microcontrollers support a wide range of data connectivity options like Ethernet, Local Interconnect Network (LIN), FlexRay, DSPI, and CAN-FD.
MIPS microcontrollers come with the RISC instruction set architecture. You’ll mostly find them in electronic devices like advanced networking modules, small microcontrollers, game consoles, office automation products, and set-top boxes.
MIPS Technologies manufactures MIPS 32-bit and MIPS 64-bit MCUs for automotive ECUs. These CPUs are code-efficient, require less power, and come at a low cost. Some MIPS 64-bit MCUs are ideal for high-end automotive applications because the latter need higher processing capabilities and graphics rendering.
Car manufacturers mostly use the MIPS 32-bit microcontrollers to automate the electronic controls within the car.
For example, electronic doors, hoods, windshield wipers, automatic windows, etc., run on MIPS32 architecture-based CPUs. Some chassis and powertrain electronic systems also include the MIPS 32-bit MCU.
On the contrary, advanced systems like the infotainment system, ADAS, and autonomous driving require hardware acceleration and object recognition.
Thus, the ECU needs more processing power to make the correct decision in a high-speed environment. MIPS 64-bit MCUs are ideal for such applications.
Microchip Technology Inc. also manufactures various microcontrollers and microprocessors for car ECU applications, and the 16-bit MCUs are primarily available in the powertrain electronic control units.
They’re compatible with CAN-FD, CAN, USB, LIN, and SENT data communications protocols.
The 16-bit MCU is essentially a microcomputer with various peripherals for motor control, digital power conversion, precision speed, and torque control. It also consists of Digital Signal Controllers (DSCs) to help the MCU with additional motor control.
Various types of cars like electric cars, internal combustion engine automobiles, or hybrid-electric vehicles use several ECUs based on the 16-bit MCUs and DSCs.
The microcontroller of these ECUs comes with AEC Q100 Grade 0 certification that indicates that the CPU and its memory module are highly stable within the -40 °C to 150 °C temperature range.
The microcomputer system can withstand harsh conditions like sudden shocks, high-speed mobility, oil and grease deposition.
The 16-bit MCU is capable of running algorithms for controlling the motors, actuators, turbocharger wastegates, EGR valves, and oil/water pumps.
8-Bit MCUs are ideal for ECUs that need to run small program codes. PIC and AVR MCUs are brands of Microchip Technology Inc., and you’ll see them in various car ECUs that control analog sensors, digital sensors, and capacitive touch functionalities.
Nowadays, modern cars come with LED lighting systems for energy efficiency. You’ll find one or two ECUs controlling these LED arrays, and most of these ECUs are based on the 8-Bit microcontroller units.
The 8-Bit MCUs consume low power since they consist of core independent peripherals or CIPs. Some ECU functionalities may not always require constant processor usage. Here, CIPs play a vital role.
These microcomputers also come with intelligent analog peripherals so that the ECU can control analog sensors via an analog-to-digital signal translation.
For touch-sensitive in-car functionalities, these chips also contain a peripheral touch controller that helps it recognize and measure capacitive touch.
S32K microcontrollers are from NXP Semiconductors N.V., and these are designed on Arm Cortex-M series RISC architecture. The ECUs based on such MCUs offer advanced software, safety, and security features for smart cars.
These MCUs pass the ASIL B/D certifications, and hence, are suitable for various car ECUs which will control the body, electrical unit, and zone controls.
Most of the S32K MCUs also pass the AEC-Q100 Grade 0, Grade 1, and Grade 2 certifications so that the car manufacturers can use the processors in a rugged environment with high-temperature exposures.
S32K MCUs come in variable processing cores like dual-core, single-core, and lockstep-core. The flash memory capacity and the number of pins change according to the processing core.
Usually, these microcontrollers range from 128 kB to 8 MB in flash memory for program storage, whereas they offer two types of pin configurations: 32 to 176 pins and 48 to 289 pins.
Infineon Technologies AG manufactures an embedded system for vehicle ECUs that consists of a microcontroller, a RISC processor core, and a DSP in one microcontroller unit. These MCUs are popular as 32-Bit AURIX TriCore Microcontrollers.
You’ll frequently find these in ECUs that control the internal combustion engine, transmission control units, and electric power steering systems.
Apart from the engine and transmission, 32-Bit AURIX TriCore MCU-based ECUs are ideal for ADAS, autonomous driving control, drive safety management, and in-car connected services automation.
These CPUs are available within a processing speed range of 133 MHz to 300 MHz. The MCUs offer a minimum flash memory of 0.5 MB to up to 16 MB.
Compared with other above-mentioned MCUs, these are more powerful because of a dedicated SRAM. In terms of data connectivity, the microcomputers are compatible with CAN, LIN, FlexRay, and SPI protocols.
Now that you know about a few ECU microcontrollers, you might be thinking that these chips are less powerful than a home computer CPU. That’s correct because they need to run a few predefined codes, and in most cases, these codes are not more than one megabyte in size.
However, you’ll always find more than one ECU with different program codes for the entire car. Knowing more about your car’s ECU will help you take appropriate care of the vehicle and nourish your brain cells if you’re an automobile enthusiast.
Tamal is a freelance writer at MakeUseOf. After gaining substantial experience in technology, finance, and business processes in his previous job in an IT consulting company, he adopted writing as a full-time profession 3 years ago. While not writing about productivity and the latest tech news, he loves to play Splinter Cell and binge-watch Netflix/ Prime Video.
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