SOFTWARE ERROR PROTECTION TECHNIC FOR HIGH DENSITY MEMORY

Present microsatellite experiments generate a significant amount of data. Microsatellite on-board computers shall have large mass memory to store data while the satellite is not in ground visibility. Space radiation affects high-density memories destroying stored data (single event upset- SEU). Error Detecting and Correcting Circuit (EDAC) by adding some circuit and memory may detect and correct these errors. However, this strategy requires a large number of components. So that, microsatellite constraints of mass, power and volume lead to a software approach to protect memory against errors mainly induced by space radiation. A proposed technic uses software that implements Hamming code to protect the data memory. A comparison between the Reed-Solomon method and the proposed technic is also presented. This new approach detects single and double errors, corrects single errors and logs events by dividing the data memory into blocks of 256 words with 32 bits, nine of them used to check. In addition, to avoid that a SEU affects more than one memory cell and then causes double errors in a block, address lines of adjacent memory cells in column direction were exchanged to locate these cells in different blocks. 1