SYSTEMS FOR NON-VOLATILE STORAGE OF DATA AND POSTAGE METER SYSTEMS

摘要

The storage system includes a floating gate EEPROM non-volatile memory (108) and an EAROM NMOS non-volatile memory (106) both of which are controlled by an accounting microcomputer (104). The latter includes a read only memory which stores control routines and a random access memory having working registers. The interleaved writing to the non-volatile memories enables data to be written into them during power-down without increasing the time needed to write into either memory individually. A byte of information is written first into the EEPROM. Two milliseconds are taken during which the data are written into the memory locations following arrival at the EEPROM data line ports. During the two-milliseconds period two nibbles of data are written into the NMOS memory, at one millisecond per nibble.