The DS1302 trickle-charge timekeeping chip contains a real-time clock/calendar and 31 bytes of static RAM. It
communicates with a microprocessor via a simple serial interface. The real-time clock/calendar provides seconds,
minutes, hours, day, date, month, and year information. The end of the month date is automatically adjusted for
months with fewer than 31 days, including corrections for leap year. The clock operates in either the 24-hour or
12-hour format with an AM/PM indicator.
Interfacing the DS1302 with a microprocessor is simplified by using synchronous serial communication. Only three
wires are required to communicate with the clock/RAM: CE, I/O (data line), and SCLK (serial clock). Data can be
transferred to and from the clock/RAM 1 byte at a time or in a burst of up to 31 bytes. The DS1302 is designed to
operate on very low power and retain data and clock information on less than 1µW.
The DS1302 is the successor to the DS1202. In addition to the basic timekeeping functions of the DS1202, the
DS1302 has the additional features of dual power pins for primary and backup power supplies, programmable
trickle charger for VCC1, and seven additional bytes of scratchpad memory.
Key Features
Real-Time Clock Counts Seconds, Minutes,
Hours, Date of the Month, Month, Day of the
Week, and Year with Leap-Year Compensation
Valid Up to 2100
31 x 8 RAM for Scratchpad Data Storage
Serial I/O for Minimum Pin Count
2.0V to 5.5V Full Operation
Uses Less than 300nA at 2.0V
Single-Byte or Multiple-Byte (Burst Mode) Data
Transfer for Read or Write of Clock or RAM
Data
8-Pin DIP or Optional 8-Pin SO for Surface
Mount
Simple 3-Wire Interface
TTL-Compatible (VCC = 5V)
Optional Industrial Temperature Range:
-40°C to +85°C
Notes: *This pricing is BUDGETARY, for comparing similar parts. Prices are in
U.S. dollars and subject to change. Quantity pricing may vary
substantially and international prices may differ due to local
duties, taxes, fees, and exchange rates. For volume-specific prices
and delivery, please see the price and availability page
or contact an authorized distributor.
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