Rainbow Electronics DS1302 - Manual (Page 2)

DS1302
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Interfacing the DS1302 with a microprocessor is simplified by using synchronous serial communication.
Only three wires are required to communicate with the clock/RAM: 1)
RST (reset), 2) I/O (data line), and
3) 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 1 microwatt.
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 back-up power
supplies, programmable trickle charger for V
CC1
, and seven additional bytes of scratchpad memory.
TYPICAL OPERATING CIRCUIT