PT7C4363 Datasheet, PDF (4/22 Pages) Pericom Semiconductor Corporation – Real-time Clock Module (I2C Bus)

Data Sheet
PT7C4363
Real-time Clock Module (I²C Bus)
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Function Description
Overview of Functions
1. 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 2100.
2. Alarm function
These devices have one alarm system that outputs interrupt signals from INTA for PT7C4363 or INT/OUT/SQW for PT7C4341
to CPU when the date, day of the week, hour, minute or second correspond to the setting. Each of them may output interrupt
signal separately at a specified time. The alarm may be selectable between on and off for matching alarm or repeating alarm.
3. Programmable square wave output
A square wave output enable bit controls square wave output at pin 7. 4 frequencies are selectable: 1, 32, 1.024k, 32.768k Hz.
4. 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.
5. Oscillator fail detect
When oscillator fail, OSF bit will be set.
6. Oscillator enable/disable
Only time count chain can be enable or disable by STOP bit..
7. Timer function
The timer control register determines one of 4 source clock frequencies for the timer (4096 Hz, 64 Hz, 1 Hz, or 1/60 Hz) and
enables or disables the timer. The timer counts down from software loaded 8-bit binary value. At the end of every countdown, the
timer sets the Timer Flag (TF). The TF may only be cleared by software. The asserted TF can be used to generate an interrupt.
The interrupt may be generated as a pulsed signal every countdown period or as a permanently active signal which follows the
condition of TF. Bit TI/TP is used to control this mode selection. When reading the timer, the current countdown value is returned.
8. Reset function
The PT7C4363 includes an internal reset circuit which is active whenever the oscillator is stopped. In the reset state the I²C-bus
logic is initialized and all registers, including the address pointer, are cleared with the exception of bits FE, OSF, TD1, TD0,
TESTC and AE which are set to logic 1.
PT0207(07/05)
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