FTSPM: A Fault-Tolerant ScratchPad Memory

ScratchPad Memory (SPM) is an important part of most modern embedded processors. The use of embedded processors in safety-critical applications implies including fault tolerance in the design of SPM. This paper proposes a method, called FTSPM, which integrates a multi-priority mapping algorithm with a hybrid SPM structure. The proposed structure divides SPM into three parts: 1) a part is equipped with Non-Volatile Memory (NVM) which is immune against soft errors, 2) a part is equipped with Error-Correcting Code, and 3) a part is equipped with parity. The proposed mapping algorithm is responsible to distribute the program blocks among the above three parts with regards to their vulnerability level. The simulation results demonstrate that the FTSPM reduces the SPM vulnerability by about 7x in comparison to a pure SRAM-based SPM. In addition, the dynamic energy consumption of the proposed method is 77% and 47% less than that of a pure NVM-based SPM and a pure SRAM-based SPM, respectively.