M48T212AMH

The M48T212A is a self-contained device that includes a real time clock (RTC), programmable alarms, a watchdog timer, and two external chip enable outputs which provide control of up to four (two in parallel) external low-power static RAMs. A built-in 32.768 kHz oscillator (external crystal controlled) is used for the clock/calendar function. Access to all TIMEKEEPER functions and the external RAM is the same as conventional byte-wide SRAM.

The 16 TIMEKEEPER Registers offer Century, Year, Month, Date, Day, Hour, Minute, Second, Control, Calibration, Alarm, Watchdog, and Flags. Externally attached static RAMs are controlled by the M48T212A via the E1CON and E2CON signals (see Table 4). Automatic backup and write protection for an external SRAM is provided through VOUT, E1CON and E2CON pins. (Users are urged to insure that voltage specifications, for both the controller chip and external SRAM chosen, are similar).