ds1306et-r Maxim Integrated Products, Inc., ds1306et-r Datasheet - Page 6

• Manufacturer Part Number: ds1306et-r
• Description: Ds1306 Serial Alarm Real-time Clock
• Manufacturer: Maxim Integrated Products, Inc.

Figure 2. RTC REGISTERS AND ADDRESS MAP
Note: Range for alarm registers does not include mask’m’ bits.
The DS1306 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 DS1306 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 8 Bh to 8 Eh. 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
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, hour, and
12–1FH
20–7FH
READ
HEX ADDRESS
0AH
0DH
0BH
0CH
0EH
00H
01H
02H
03H
04H
05H
06H
07H
08H
09H
0FH
10H
11H
WRITE
92–9FH
8DH
8AH
8BH
8CH
8EH
8FH
FFH
80H
81H
82H
83H
84H
85H
86H
87H
88H
89H
90H
91H
A0–
Bit
M
M
M
M
M
M
M
M
7
0
0
0
0
0
0
Bit6
12
24
12
24
12
24
10-MIN ALARM 0
10-SEC ALARM 0
10 MIN ALARM 1
0
0
0
0
10 SEC ALARM 1
0
10-YEAR
10 MIN
10 SEC
10
10
Bit5
A
A
P
0
P
0
TRICKLE CHARGER REGISTER
10
10-MONTH
A
P
0
10-DATE
96-BYTES USER RAM
CONTROL REGISTER
10-HR
10-HR
STATUS REGISTER
10-HR
Bit4
0
0
0
RESERVED
6 of 21
—
Bit3
0
0
0
Bit2
HOUR ALARM 0
HOUR ALARM 1
MIN ALARM 0
MIN ALARM 1
SEC ALARM 0
SEC ALARM 1
MONTH
DAY ALARM 0
DAY ALARM 1
HOURS
YEAR
DATE
MIN
SEC
Bit1
DAY
Bit0
01–12 + P/A
01–12 + P/A
01–12 + P/A
RANGE
—
—
—
—
—
00–23
00–23
00–23
00–59
00–59
01–07
01–12
00–99
00–59
00–59
01–07
00–59
00–59
01–07
1–31