Battery backed memory has an internal lithium power source and a self-contained control circuitry which constantly monitors VCC for any out-of-tolerance conditions. If such a condition occurs, the lithium battery will automatically switch on and the memory’s write protection is unconditionally enabled in order to prevent data corruption. The number of write cycles that can be executed have no limit and there is no additional support circuitry that is required for microprocessor interfacing. Data can be reliably stored for several years solely on battery power, and data can be stored for a much longer period when VCC is powered. Static random-access memory, or SRAM, is a type of semiconductor memory which uses bistable latching circuitry in order to store each bit. SRAM is different from dynamic RAM (DRAM), which must be refreshed periodically.