Protection unit for radiation induced errors in flash memory systems

Bryer, Bevan (2004-12)

Thesis (MScEng)--University of Stellenbosch, 2004.

Thesis

ENGLISH ABSTRACT: Flash memory and the errors induced in it by radiation were studied. A test board was then 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 valuable insight into flash memory behaviour. To date, the board is still being used to test various flash devices for radiation-harsh environments. A memory protection unit (MPU) was conceptually designed and developed to morntor flash devices, increasing their reliability in radiation-harsh environments. This unit was designed for intended use onboard a micro-satellite. The chosen flash device for this study 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 the design was implemented in field programmable gate arrays and was realised using VHDL. Simulations were performed to verify the functionality of the design subsystems. These simulations showed that the various emulated errors were handled successfully by the MPU. A modular design methodology was followed, therefore allowing the chosen flash device to be replaced with any flash device, following a small reconfiguration. This also allows parts of the system to be duplicated to protect more than one device.

AFRIKAANSE OPSOMMING: 'n Studie is gemaak van" Flash" geheue en die foute daarop wat deur radiasie veroorsaak word. 'n Toetsbord is ontwerp en ontwikkel asook 'n radiasie toetsprogram waarna die stelsel bestraal is. Die resultate was suksesvol en het aspekte van die studie bevestig en belangrike insig gegee ten opsigte van "flash" komponente in radiasie intensiewe omgewmgs. 'n Geheue Beskermings Eenheid (GBE) is konseptueel ontwerp en ontwikkelom die "flash" komponente te monitor. Dit verhoog die betroubaarheid in radiasie intensiewe omgewings. Die eenheid was ontwerp met die oog om dit aan boord 'n mikro-satelliet te gebruik. Die gekose "flash" komponent vir die studie was die K9F1208XOA model van SAMSUNG. Die GBE is ontwerp om foute wat deur radiasie geïnduseer word in die "flash" komponent te identifiseer, herstel en reg te maak. Die grootste deel van die implementasie is gedoen in "field programmable gate arrays" and is gerealiseer deur gebruik te maak van VHDL. Simulasies is gedoen om die funksionaliteit van die ontwikkelde substelsels te verifieer. Hierdie simulasies het getoon dat die verskeie geëmuleerde foute suksesvol deur die GBE hanteer is. 'n Modulre ontwerpsmetodologie is gevolg sodat die gekose "flash" komponent deur enige ander flash komponent vervang kan word na gelang van 'n eenvoudige herkonfigurasie. Dit stelook dele van die sisteem in staat om gedupliseer te word om sodoende meer as een komponent te beskerm.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/50070
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