Live & Seamless Firmware Upgrade in Real Time Control Systems

High Availability systems e.g. Server power, and factory automation require uninterrupted operations, regardless of maintenance cycles or functionality upgrades. Conventionally redundant controllers are used to act as a backup in such scenarios resulting in double the cost of the hardware. This paper proposes a single real-time controller, that enables live firmware upgrade in such systems, reducing the cost of the hardware. The key challenge of using single controller is to perform firmware upgrade without resetting the controller to avoid halt in real-time operation. The paper proposes an approach to achieve a seamless switchover without resetting the device. It introduces novel techniques namely, hardware support for interrupt vector & function pointer swapping, compiler support to enable LFU, and optimal switchover point. The proposed solution is implemented in Real time systems using C2000™ MCU for DC-DC buck converter, and achieves less than few clocks (<< 1usec) of switch-over time, hence making the transition to upgraded firmware seamless on a live system with real-time operation control.