PT7C4307_13 Datasheet, PDF (7/15 Pages) Pericom Semiconductor Corporation – Real-time Clock Module

PT7C4307
Real-time Clock Module (I²C Bus)
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Function Description
Clock function
Since the output of the I/O pin SDA is open drain, a pull-up
CPU can read or write data including the year (last two digits), resistor should be used on the circuit board if the CPU output
month, date, day, hour, minute, and second. Any (two-digit) I/O is also open drain.
year that is a multiple of 4 is treated as a leap year and
calculated automatically as such until the year 2099.
The SCL's maximum clock frequency is 400 kHz, which
supports the I²C bus's high-speed mode.
Programmable square wave output
Oscillator enable/disable
A square wave output enable bit controls square wave output
Oscillator can be enabled or disabled by /EOSC bit. But time
at pin 7. 4 frequencies are selectable: 1, 4.096k, 8.192k,
count chain does not shut down when the bit is logic 1.
32.768k Hz.
RAM
Interface with CPU
Data is read and written via the I²C bus interface using two
568 nonvolatile RAM are available for customer use.
signal lines: SCL (clock) and SDA (data).
Registers
Allocation of registers
Addr.
(hex)^*1
Function
Register definition
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
00 Seconds (00-59)
/EOSC^*2
S40
S20
S10
S8
S4
S2
S1
01 Minutes (00-59)
0
M40
M20
M10
M8
M4
M2
M1
02 Hours (00-23 / 01-12)
H20 or
0
12, /24
H10
H8
H4
H2
H1
P, /A
03 Days of the week (01-07)
0
0
0
0
0
W4
W2
W1
04 Dates (01-31)
0
0
D20
D10
D8
D4
D2
D1
05 Months (01-12)
0
0
0
MO10 MO8
MO4
MO2
MO1
06 Years (00-99)
Y80
Y40
Y20
Y10
Y8
Y4
Y2
Y1
07 Control^*3
OUT^*4
0
0
SQWE^*5
0
0
RS1^*6
RS0^*6
08~3F RAM^*7
-
-
-
-
-
-
-
-
Caution points:
*1. PT7C4307 uses 6 bits for address. That is if write data to 41H, the data will be written to 01H address register.
*2. Oscillator Enable bit. When this bit is set to 1, oscillator is stopped but time count chain is still active.
*3. Control register was used to select SQW/OUT pin output square wave with one of 4 kinds of frequency or DC level.
*4. Control SQW/OUT pin output DC level when square wave is disabled.
*5. Square wave outputs enable at SQW/OUT pin.
*6. Square wave output frequency select.
*7. PT7C4307 has 568 static RAM for customer use. It is volatile RAM.
*8. All bits marked with "0" are read-only bits. Their value when read is always "0". All bits marked with "-" are customer using
space.
2013-06-0002
PT0206-5 06/18/13
7