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2014-10-0002

PT0480-2

11/03/14

11

PT7C4337A/4337AC

Real-time Clock Module (I



A2F

Alarm 2 Flag.

A1F

Data

Description

Read /

Write

0

The time do not match the alarm 2 registers.

Default

Read

1

Indicates that the time matched the alarm 1 registers. This flag can be used to generate an interrupt on

either INTA or SQW/INTB depending on the status of the INTCN bit. If the INTCN = 0 and A2F = 1

(and A2IE = 1), the INTA pin goes low. If the INTCN = 1 and A2F = 1 (and A2IE = 1), the

SQW/INTB pin goes low. A2F is cleared when written to logic 0. Attempting to write to logic 1 leaves

the value unchanged.

Time Counter

Time digit display (in BCD code):



Second digits: Range from 00 to 59 and carried to minute digits when incremented from 59 to 00.



Minute digits: Range from 00 to 59 and carried to hour digits when incremented from 59 to 00.



Hour digits: See description on the /12, 24 bit. Carried to day and day-of-the-week digits when incremented from 11 p.m. to

12 a.m. or 23 to 00.

Addr.

(hex)

Description

D7

D6

D5

D4

D3

D2

D1

D0

00

Seconds

0

S40

S20

S10

S8

S4

S2

S1

(default)

0

0

0

0

0

0

0

0

01

Minutes

0

M40

M20

M10

M8

M4

M2

M1

(default)

0

0

0

0

0

0

0

0

02

Hours

0

12, /24

H20 or P,/A

H10

H8

H4

H2

H1

(default)

0

0

0

0

0

0

0

0

Note: Any registered imaginary time should be replaced with correct time, otherwise it will cause the clock counter malfunction.



12, /24 bit

This bit is used to select between 12-hour clock system and 24-hour clock system.

12, /24

Data

Description

Read / Write

0

24-hour system

1

12-hour system