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2013-06-0002

PT0206-5

06/18/13

7

PT7C4307

Function Description

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 I

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 I

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.

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)

0

12, /24

H20 or

P, /A

H10

H8

H4

H2

H1

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.