Entry-level MCUs reduce system costs and complexity in safety-critical applications

To assist engineers in meeting stringent safety requirements while minimising design costs and complexity, Microchip Technology has released the AVR SD family of MCUs. The MCUs feature built-in functional safety mechanisms and are designed to support applications requiring rigorous safety assurance. Paired with a dedicated safety software framework, this is the first entry-level MCU of its kind – at this price point – designed to meet Automotive Safety Integrity Level C (ASIL C) and Safety Integrity Level 2 (SIL 2) requirements, which mandate redundant safety checks. Further improving the safety credentials of the AVR SD family, the MCUs follow a functional safety management system that has been certified by TÜV Rheinland.

Hardware safety features include a dual-core lockstep CPU, dual ADCs, ECC on all memories, a dedicated error controller module, error injection mechanisms and voltage and clock monitors. These features reduce fault detection time and software complexity. The AVR SD family can detect internal faults quickly and deterministically, allowing applications to meet stringent Fault Detection Time Interval (FDTI) targets as low as 1ms, helping prevent hazardous situations and increasing reliability.

The hardware features work with the company's safety framework software to manage functional safety diagnostics so the MCUs can detect and handle errors autonomously, initiating a safe state when required. The MCUs can be used as the main processor for crucial functions, such as detecting thermal runaways or monitoring sensor data like rotary positions, at minimal power consumption. It is also an outstanding candidate for a coprocessor in complex systems to mirror or offload safety-critical functions for applications targeting higher safety integrity levels up to ASIL D and SIL 3.

"When designing safety-critical applications, engineers have typically been limited to using expensive and complicated devices. By integrating specific safety features directly into an entry-level MCU and providing a supporting software framework, we are helping our customers meet stringent safety standards with greater efficiency," said Greg Robinson, corporate vice president of Microchip's MCU business unit. "With the AVR SD family, designers can significantly reduce development time and minimise system and certification costs."

The AVR SD MCUs are designed in compliance with the International Organization for Standardization (ISO) 26262 and International Electrotechnical Commission (IEC) 61508 standards. Safety standards are implemented across various industries such as aerospace and defence, industrial automation, automotive and medical sectors. Specific applications include flight control systems, ignition control, robotics safety functions, ADAS and medical infusion pumps.