| 摘要 |
Systems and devices in which multi-bit phase change memory is used, including memory systems and memories, as well as methods for operating such systems and devices. According to the present invention, a reference corresponding to a pair of adjacent logical states (e.g., 0 and 1) can be generated by averaging outputs from multiple phase change memory reference cells designated to store said adjacent logical states. By writing reference cells contemporaneously with words of cells that are configured to be written together, resulting references can closely track output changes in corresponding ones of said words resulting from, e.g., drift and other time- and phase change material-dependent factors. Ordering of states within said reference cells can be used to encode information such as checksums of corresponding words. |
