Virtual Switches and Indicators in Automotive Displays 2020-01-1362
Over the last decade, graphical and touch displays have become commonplace in automobile cockpits. Such displays have been used mainly for convenience functions such as navigation, radio, driver information, and vehicle settings. Automakers are now using these displays to generate “virtual” indicators that replace regulated and/or safety-critical physical indicators, such as gear position indication or the Malfunction Indicator Light [MIL]. Automakers are also replacing physical switches and controls, such as heating, ventilation, and air conditioning [HVAC] controls, with “virtual” controls rendered on the cockpit touch-screen. Many of these indicators and controls have regulatory and/or functional safety requirements that have been met using such methods as redundant terminals in a safety-critical switch, or by monitoring the electrical State-of-Health [SOH] of discrete LED indicators. Meeting these requirements with “virtual” graphical elements requires new electronic hardware and software technologies. This paper discusses recent advances in electronic hardware and System-on-Chip [SoC] solutions, operating systems, and supporting software architecture implementation of regulatory and/or functional safety graphics within cockpit displays. Application of the ISO 26262 standard, particularly section 5, and considerations needed to meet “freedom of interference” imperatives are discussed in detail. End-To-End [E2E] network protection between different Electronic Control Units [ECUs] as well as within a single ECU between different microprocessors and/or software processes is examined. Hardware monitoring requirements within the display panel, backlighting, and touch screen are also discussed. An example system design is presented to illustrate alternatives and associated tradeoffs.