ADAS: Innovations for Human Safety

As the automotive sector continues to evolve with increased electronic content, a lot of stress is being put to make the cars much safer than ever before. Big car manufacturers now more than ever are increasing their focus and energy to make their cars safer for drivers, passengers as well as for pedestrians. The current thought process is to help drivers in preventing an accident from occurring rather than just stressing upon the safety for car occupants after an accident has happened.

This pro-active safety concept has opened up a lot of brand new possibilities in a relatively new field in automotive domain called as Advanced Driver Assistance Systems or ADAS. This domain along with the traditional safety and chassis domains are together creating new markets for semiconductor organizations.

These domains encapsulate several technologies, such as lane departure warning, adaptive cruise control, blind spot detection, airbags, electronic power steering, active braking systems, night vision, adaptive cruise control and collision warning systems, based on camera and radar. Some of these technologies have been there for quite some time. But newer technologies based on various camera and radar systems are now evolving rapidly, and deployment of these systems in next generation cars is rapidly increasing.

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SAFETY MICROCONTROLLERS DESIGN AND CHALLENGES
Hardware diversity requirements coupled with various diagnostic coverage parameters enforce a lot of complex requirements on SoC designers, especially in designing devices catering to the automotive electronics applications. A high-end ADAS system requires high-performance cores for carrying out complicated motor control or image processing algorithms, video camera and DDR interfaces in the noisy automotive environment. Adherence to functional safety rules as well as challenges involved in a high performance SoC design makes these architectures much more challenging than a normal SoC design flow.


Figure 1: Some examples of automotive safety technologies in Advanced Driver Assistance Systems.

Freescale has several innovative 8/16/32-bit MCUs and sensors designed specifically for this market. The MPC564xL family of dual-core, dual-issue 32-bit MCUs, for instance, is architected to help system designers meet very strict FIT rates in SIL3 and ASIL-D safety standards. These standards are accepted as minimum criteria for various safety critical systems. Processors from this family help reduce burden on safety system designers by providing a lot of key functionalities on a single chip while taking care of various functional safety aspects. Specific applications targeted with MPC564xL include electric power steering; short and mid-range adaptive cruise control, RADAR and LIDAR; vehicle dynamic and chassis control; ABS braking systems; electronic stability program (ESP); blind spot detection; pre-crash detection; and in hybrid electric vehicles (HEVs).

Catering to a variety of tasks, the MPC564xL family has several key functionalities built inside the SoC. These include static switching support for the MCUs between two operational modes based on system safety requirements; flexible hardware self test capabilities, which provide diagnostic coverage at both logic and memory level; on-chip fault collection and control unit, which ensures that all the faults are collected and properly routed inside and outside to the system; motor control; 12-bit ADCs in the chip, which ensure precise conversion for various input waveforms; and support for robust communications channels such as FlexRay, CAN, etc., to ensure that data and control transfers with other MCUs goes smoothly in the automotive environment.