Teppei Hirotsu

A Cost-Effective Dependable Microcontroller Architecture with Instruction-Level Rollback for Soft Error Recovery

A cost-effective, dependable microcontroller architecture has been developed. To detect soft errors, we developed an electronic design automation (EDA) tool that generates optimized soft error-detecting logic circuits for flip-flops. After a soft error is detected, the error detection signal goes to a developed rollback control module (RCM), which resets the CPU and restores the CPUs register file from the backup register file using a rollback program routine. After the routine, the CPU restarts from the instruction executed before the soft error occurred. In addition, there is a developed error reset module (ERM) that can restore the RCM from soft errors. We also developed an error correction module (ECM) that corrects ECC errors in RAM after error detection with no delay overheads. Testing on a 32- bit RISC microcontroller and EEMBC benchmarks showed that the area overhead was under 59% and frequency overhead was under 9%. In a soft error injection simulation, the MTBF of random logic circuits, and the MTBF of RAM were 30 and 1.34 times longer, respectively, than those of the original microcontroller.