DS1305 Maxim Integrated Products, DS1305 Datasheet - Page 6

• Manufacturer Part Number: DS1305
• Description: IC RTC SERIAL ALARM 16-DIP
• Manufacturer: Maxim Integrated Products
• Type: Clock/Calendar/Alarmr

Specifications of DS1305

• Memory Size: 96B
• Time Format: HH:MM:SS (12/24 hr)
• Date Format: YY-MM-DD-dd
• Interface: SPI, 3-Wire Serial
• Voltage - Supply: 2 V ~ 5.5 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Through Hole
• Package / Case: 16-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

READING FROM THE CLOCK REGISTERS
Buffers are used to copy the time and date register at the beginning of a read. When reading in burst
mode, the user copy is static while the internal registers continue to increment.
Figure 2. RTC REGISTERS AND ADDRESS MAP
Note: 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 to 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 2). When all of the mask bits are logic 0, a time-
of-day alarm only occurs 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 is generated every day when bit 7 of
the day alarm register is set to a logic 1. An alarm is generated every hour when bit 7 of the day and hour
alarm registers is set to a logic 1. Similarly, an alarm is generated every minute when bit 7 of the day,
12h–1Fh
20h–7Fh
READ
0Ah
0Bh
0Ch
0Dh
0Eh
HEX ADDRESS
00h
01h
02h
03h
04h
05h
06h
07h
08h
09h
0Fh
10h
11h
—
—
A0h–FFh
92h–9Fh
WRITE
8Ch
8Dh
8Ah
8Bh
8Eh
8Fh
80h
81h
82h
83h
84h
85h
86h
87h
88h
89h
90h
91h
—
—
Bit7
M
M
M
M
M
M
M
M
0
0
0
0
0
0
Bit6
12
24
12
24
12
24
0
0
0
0
0
10 Seconds Alarm
10 Seconds Alarm
10 Minutes Alarm
10 Minutes Alarm
10 Year
10 Seconds
10 Minutes
Bit5
10
10
10
P
A
P
A
P
A
0
0
0
10 Month
10 Date
Trickle Charger Register
96 Bytes User RAM
10 Hour
10 Hour
10 Hour
Control Register
Status Register
Bit4
Reserved
0
0
0
Alarm 0
Alarm 1
6 of 22
Bit3
Seconds Alarm
Seconds Alarm
Minutes Alarm
Minutes Alarm
Bit2
Hour Alarm
Hour Alarm
Day Alarm
Day Alarm
Seconds
Minutes
Month
Hours
Date
Year
Day
Bit1
Bit0
01–12 + P/A
01–12 + P/A
01–12 + P/A
RANGE
00–FF
00–59
00–59
00–23
01–12
00–99
00–59
00–59
00–23
01–07
00–59
00–59
00–23
01–07
1–31
1–7
—
—
—
—
—
—