| 摘要 |
PURPOSE:To take out valid data even when a power source is disconnected or a battery for back up is run out while data are written in an NVRAM by using an SRAM and the NVRAM. CONSTITUTION:The content of a buffer RAM 25c in a system control circuit 25 of a tape recorder is written in a static memory (SRAM) 37 every constant cycle or data change, and written in a nonvolatile memory (NVRAM) 36 when the power source is turned off. The SRAM 37 is backed up by a battery 45 for back up. When the power source is turned on, the data from the SRAM 37 are preferentially used, and when an error occurs in the data of the SRAM 37, the data from the NVRAM 36 are used. |
