Electronic circuits, such as microprocessors, are today used in all types of environments, including space and locations on earth where they are exposed to radiation. We then risk that high energy particles enter the circuit and cause a malfunction, possibly with critical outcome for a satellite or other equipment that the microprocessor controls. The memory of a microprocessor is particularly vulnerable, since a change to a stored value will be remembered and is not simply an instantaneous event.
Another major challenge for modern electronic circuits is their power consumption. This is the case from the smallest sensor node, running on, e.g. solar energy harvesting or irreplaceable coin cell batteries, through cell phones needing recharge frequently, to large data centres, where both the electricity bill and the heating of the microprocessors themselves are problems. One approach to save power is to reduce the supply voltage of the circuit. A consequence of this is reduced performance, however. A possible solution is to perform dynamic adaptation while the system is running in accordance with the current requirements of the system.
The goal of the PALMERA project is to design a low power and fault tolerant microprocessor memory through a combination of hardware and software approaches. We will develop circuit level solutions where each memory cell is made robust against radiation strikes. How much energy from a particle the memory can tolerate, is however dependent on its supply voltage. We will therefore control the circuit level solution with software that detects the current radiation status. It adapts the supply voltage so that we save power when no high energy particles are hitting the memory, thus saving power, and increase the supply voltage when high radiation tolerance is required.
