Intelligent Signature Watchdog for TriCore Architecture

Published:2011/4/29 0:52:00 Author:Amy From:SeekIC

An intelligent Signature Watchdog was introduced from Infineon Technologies for use along with the company’s 32-Bit TriCore microcontrollers and the dedicated SafeTcore software. It offers monitoring functions subjected to the functional safety requirement according to the IEC61508 and ISO26262 automotive industry standards.

The CIC61508 is a safety watchdog. It can be attached into safety relevant applications including Vehicle Stability Control (VSC), Electric Power Steering (EPS), airbag control, damping systems, and powertrain controls. The watchdog monitors the main microcontroller and is intended for embedded systems by providing founctions to detect common failure modes of clock, power supply and temperature related computational errors on the microcontroller.

Safety electronics is one of the crucial drivers for reducing road errors. As we can see, legislation of mandatory application of electronically controlled active and passive safety systems has become a trend for government. What’s more, the safety aspects in fields such as EPS also helps to reduce fuel consumption by providing a general improvement in vehicle energy efficiency and thus to reduce CO2 emissions.

Safety Integrity Level (SIL, according to IEC61508) or Automotive Safety Integrity Level (ASIL, defined by ISO26262) needs particular safety measures to prevent unreasonable risk. There are four SIL (1-4) or ASIL levels (A-D) where D represents the most and A the least stringent level of a given safety function. In order to help customers reach the SIL certification, PRO-SIL safety products are introduced to them. It includes SIL-supporting safety hardware, software and documentation. Key components of the Infineon safety solution covers TriCore-based microcontrollers, the new signature watchdog CIC61508, the dedicated SafeTcore software library, and a complete documentation.

An independent watchdog device is needed for safety systems. It implements a powerful monitoring way for main microcontroller supervision in ISO26262 and IEC61508 compliant safety applications. The latest version of the ISO26262 part 5 defined that a coded window watchdog (normally SPI interface) has to meet ASIL C or ASIL D’s need, and it is a higher requirement than the simple pin toggle window watchdog which is adopted in less demanding applications. The Infineon CIC61508 used as an independent diagnostic monitoring device to get the safety relevant system to be ASIL-D approved.

The CIC61508 supports these test features which stored in its ROM. It includes an internal opcode test scheduler/sequencer, and generates a sequence of test requests with specific data and checks the response against a user defined table.

The CIC61508 has the advantages of space saving and cost-effective. Its engineering samples has a wide ambient temperature range from -40 °C to 140 °C with volume production planned for Q2 2011. The CIC61508 is supported by the SafeTcore software package featuring microcontroller core and peripherals tests to support functional safety applications according to IEC61508/ISO26262.

With regard to TriCore microcontroller family, Hitex Development Tools’s 32-bit SafeTkit provides an introduction to the Infineon safety system. It is the heart of an ASIL-D/SIL3 capable platform in an easy-to-configure and easy-to-use format. The SafeTkit adopts a TriCore evaluation board with the CIC61508 and the SafeTcore test library. A whole set of documentation includes safety manuals and quick start guide to complete the safety kit. Hitex has an entire tool chain covering a TriCore compiler evaluation licence, a safety demonstration application and a test bench. All the major safety features are available. In order to assess their effect on system behavior and gain an understanding of the underlying concepts, they also can be reconfigured. The related integrated circuit is IT150-S.

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