DS1305N View Datasheet(PDF) - Dallas Semiconductor -> Maxim Integrated

Part Name

Description

Manufacturer

DS1305N

Serial Alarm Real Time Clock (RTC)

Dallas Semiconductor -> Maxim Integrated 

RTC REGISTERS Figure 3

DS1305

RTC Registers DS1305

HEX ADDRESS Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

READ WRITE

00H

80H

0

10 SEC

SEC

01H

81H

0

10 MIN

MIN

02H

82H

0 12/2 10 10 HR

HOURS

4 P/A

03H

83H

0

0

0

0

DAY

04H

84H

0

0

10 DATE

DATE

05H

85H

0

0

10 MONTH

MONTH

06H

86H

10 YEAR

YEAR

Alarm 0

07H

87H

M

10 SEC ALARM

SEC ALARM

08H

88H M

10 MIN ALARM

MIN ALARM

09H

89H

M 12/2 10 10 HR

HOUR ALARM

4 P/A

0AH

8AH

M

00

0

DAY ALARM

Alarm 1

0BH

8BH

M

10 SEC ALARM

SEC ALARM

0CH

8CH

M

10 MIN ALARM

MIN ALARM

0DH

8DH

M 12/2 10 10 HR

HOUR ALARM

4 P/A

0EH

8EH M 0 0

0

DAY ALARM

0FH

8FH

CONTROL REGISTER

10H

90H

STATUS REGISTER

11H

91H

TRICKLE CHARGER REGISTER

12-1FH 92-9FH

RESERVED

RANGE

00-59

00-59

01-12 + P/A

00-23

01-07

1-31

01-12

00-99

00-59

00-59

01-12 + P/A

00-23

01-07

00-59

00-59

01-12 + P/A

00-23

01-07

Range For Alarm Registers Does Not Include Mask’m’ Bits.

The DS1305 can be run in either 12-hour or 24-hour mode. Bit 6 of the hours register is defined as the

12- or 24-hour mode select bit. When high, the 12-hour mode is selected. In the 12-hour mode, bit 5 is

the AM/PM bit with logic high being PM. In the 24-hour mode, bit 5 is the second 10-hour bit (20-23

hours).

The DS1305 contains two time of day alarms. Time of Day Alarm 0 can be set by writing to registers

87h to 8Ah. Time of Day Alarm 1 can be set by writing to registers 8Bh to 8Eh. The alarms can be

programmed (by the INTCN bit of the Control Register) to operate in two different modes - each alarm

can drive its own separate interrupt output or both alarms can drive a common interrupt output. Bit 7 of

each of the time of day alarm registers are mask bits (Table 1). When all of the mask bits are logic 0, a

time of day alarm will only occur once per week when the values stored in timekeeping registers 00h to

03h match the values stored in the time of day alarm registers. An alarm will be generated every day

when bit 7 of the day alarm register is set to a logic 1. An alarm will be generated every hour when bit 7

of the day and hour alarm registers is set to a logic 1. Similarly, an alarm will be generated every minute

when bit 7 of the day, hour and minute alarm registers is set to a logic 1. When bit 7 of the day, hour,

minute and seconds alarm registers is set to a logic 1, alarm will occur every second.

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