DS1216B

The DS1216B SmartWatch/RAM 16/64K is a 28pin, 600-mil wide DIP socket with a builtin CMOS watch function, a nonvolatile RAM controller circuit, and an embedded lithium energy source. It accepts either 24pin 2K x 8 or 28pin 8K x 8 JEDEC bytewide CMOS static RAM. When the socket is mated with a CMOS SRAM, it provides a complete solution to problems associated with memory volatility and uses a common energy source to maintain time and date. A key feature of the SmartWatch is that the watch function remains transparent to the RAM. The SmartWatch monitors VCC for an outoftolerance condition. When such a condition occurs, an internal lithium energy source is automatically switched on and write protection is unconditionally enabled to prevent loss of watch and RAM data.

Using the SmartWatch saves PC board space since the combination of SmartWatch and the mated RAM take up no more area than the memory alone. The SmartWatch uses pins 28, 27, 26, 22, 20, 11, and 1 for RAM and watch control. All other pins are passed straight through to the socket receptacle.

The SmartWatch provides timekeeping information including hundredths of seconds, seconds, minutes, hours, day, date, month, and year information. The date at the end of the month is automatically adjusted for months with less than 31 days, including correction for leap years. The SmartWatch operates in either 24hour or 12hour format with an AM/PM indicator.