The DS1302M/TR is a trickle-charged timekeeping chip containing 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 correction for leap year. The clock operates in either the 24-hour or 12-hour format with an AM/PM indicator.

Applications

• Embedded Systems
• Data Logging
• Instrumentation
• Point-of-Sale Terminals
• Industrial Controllers

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
• Wide Operating Voltage: 2.0V to 5.5V
• Single-Byte or Multiple-Byte (Burst Mode) Data Transfer for Read or Write of Clock or RAM Data
• 8-Pin DIP and Optional SO Packages
• Simple 3-Wire Interface
• TTL-Compatible (VCC = 5V)
• Optional Industrial Temperature Range

Benefits

• Provides accurate timekeeping functionality for embedded systems.
• Simple serial interface reduces pin count and simplifies integration.
• On-chip RAM provides space for storing system data.
• Leap-year compensation ensures accurate date keeping for many years.
• Wide operating voltage range allows for flexibility in system design.

Additional Details

The DS1302M/TR uses a low-power design that allows it to operate for extended periods on a battery backup. The serial interface consists of three lines: CE (Chip Enable), I/O (Data Input/Output), and SCLK (Serial Clock). The clock’s registers and RAM can be accessed using single-byte or multiple-byte (burst mode) data transfers. The part is available in both 8-pin DIP and SO packages. The trickle-charge capability allows the user to recharge a backup battery while the device is in operation.