PT7C4307 Datasheet, PDF (5/20 Pages) Pericom Semiconductor Corporation – Real-time Clock Module (I2C Bus)

Preliminary Data Sheet
PT7C4307
Real-time Clock Module (I²C Bus)
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Function Description
Overview of Functions
Clock function
CPU can read or write data including the year (last two digits), month, date, day, hour, minute, and second. Any (two-digit) year
that is a multiple of 4 is treated as a leap year and calculated automatically as such until the year 2099.
Programmable square wave output
A square wave output enable bit controls square wave output at pin 7. 4 frequencies are selectable: 1, 4.096k, 8.192k, 32.768k Hz.
Interface with CPU
Data is read and written via the I²C bus interface using two signal lines: SCL (clock) and SDA (data).
Since the output of the I/O pin SDA is open drain, a pull-up resistor should be used on the circuit board if the CPU output I/O is
also open drain.
The SCL's maximum clock frequency is 400 kHz, which supports the I²C bus's high-speed mode.
Oscillator enable/disable
Oscillator can be enabled or disabled by /EOSC bit. But time count chain does not shut down when the bit is logic 1.
RAM
56×8 nonvolatile RAM are available for customer use.
PT0206(02/05)
5
Ver: 0