Freescale, ST roll safety-critical automotive controllerMUNICH, Germany As a result of their collaboration in the automotive semiconductor market, Freescale and STMicroelectronics have devised a microcontroller dedicated to safety-critical functions. In the chip, techniques known from avionics have made inroads.
With x-by-wire functions such as electronic brake and electronic steering, vehicle dynamics control or advanced driver assistant systems becoming a topic for automotive designers, safety considerations have become a ubiquitous topic at automotive designer meetings such as the VDI automotive electronics congress in Baden-Baden (Germany). Freescale and ST chose this year's event to roll out their safety dual-core microcontroller.
The dominating approach for x-by-wire systems is the concept of 'functional safety', explained Thomas Boehme, global marketing manager for Freescale's chassis, safety and driver assistance solutions. The high safety requirements expressed by the functional safety approach led to the creation of related standards such as IEC61508 (SIL3) and the more automotive-focused standard ISO26262. To name just one example, in a chip design team developing in accordance with these standards, a safety manager has to be named who has to be independent of the group manager.
Like in avionics where all important functions are implemented at least twice, semiconductors to be used in safety-relevant automotive functions have to be implemented redundantly and they have to monitor each other mutually. In the case of a failure, the system has to fall back into a safe operation mode.
In their SPC56EL and the MPC564xL (two identical products but marketed separately by ST and Freescale), two 32-bit Power processor cores constantly monitor each other. All computational elements are duplicated on the chip.
However, for the sake of flexibility, the cores also can be used independently of each other. This supports another approach in automotive electronics: Concentration of (software) functions on fewer hardware platforms and thus reducing the number of in-car ECUs.
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