DS1306

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DESCRIPTION

The DS1306 Serial Alarm Real Time Clock provides a full BCD clock calendar which is accessed via a

simple serial interface. The clock/calendar provides seconds, minutes, hours, day, date, month, and year

information. The end of the month date is automatically adjusted for months with less than 31 days,

including corrections for leap year. The clock operates in either the 24-hour or 12-hour format with

AM/PM indicator. In addition 96 bytes of nonvolatile RAM are provided for data storage.

level that is compatible with the interface logic. This allows an easy interface to 3-volt logic in mixed

supply systems. The DS1306 offers dual power supplies as well as a battery input pin. The dual power

supplies support a programmable trickle charge circuit which allows a rechargeable energy source (such

be backed up by a non-rechargeable battery. The DS1306 is fully operational from 2.0 to 5.5 volts.

Two programmable time of day alarms are provided by the DS1306.

Each alarm can generate an

interrupt on a programmable combination of seconds, minutes, hours, and day. “Don’t care” states can be

inserted into one or more fields if it is desired for them to be ignored for the alarm condition. A 1 Hz and

a 32 kHz clock output are also available.

The DS1306 supports a direct interface to Motorola SPI serial data ports or standard 3-wire interface. An

easy-to-use address and data format is implemented in which data transfers can occur 1 byte at a time or

in multiple-byte burst mode.

OPERATION

The block diagram in Figure 1 shows the main elements of the Serial Alarm RTC.

The following

paragraphs describe the function of each pin.

DS1306 BLOCK DIAGRAM Figure 1