M48T35-70PC1 (STMICROELECTRONICS)

The M48T35-70PC1 is a non-volatile Static RAM and Real-time Clock. It provides a highly integrated battery-backed memory and real-time clock solution. The M48T35 is a non-volatile pin and function equivalent to any JEDEC standard 32kB x 8 SRAM. It also easily fits into many ROM, EPROM and EEPROM sockets, providing the non-volatility of PROMs without any requirement for special WRITE timing or limitations on the number of WRITEs that can be performed. The clock locations contain the year, month, date, day, hour, minute and second in 24-hour BCD format. Corrections for 28, 29 (leap year - valid until 2100), 30 and 31 day months are made automatically. Byte 7FF8h is the clock control register. This byte controls user access to the clock information and also stores the clock calibration setting. The eight clock bytes are not the actual clock counters themselves, they are memory locations consisting of BiPORT™ READ/WRITE memory cells.