Protection unit for radiation induced errors in flash memory systems

[摘要] ENGLISH ABSTRACT:Flash memory and the errors induced in it by radiation were studied. A test board wasthen designed and developed as well as a radiation test program. The system was irradiated.This gave successful results, which confirmed aspects of the study and gave valuableinsight into flash memory behaviour. To date, the board is still being used to test variousflash devices for radiation-harsh environments.A memory protection unit (MPU) was conceptually designed and developed to morntorflash devices, increasing their reliability in radiation-harsh environments. This unitwas designed for intended use onboard a micro-satellite. The chosen flash device for thisstudy was the K9F1208XOA model from SAMSUNG. The MPU was designed to detect,maintain, mitigate and report radiation induced errors in this flash device. Most of thedesign was implemented in field programmable gate arrays and was realised using VHDL.Simulations were performed to verify the functionality of the design subsystems. Thesesimulations showed that the various emulated errors were handled successfully by theMPU.A modular design methodology was followed, therefore allowing the chosen flash deviceto be replaced with any flash device, following a small reconfiguration. This also allowsparts of the system to be duplicated to protect more than one device.

[发布机构] Stellenbosch University