DS1347 Maxim, DS1347 Datasheet - Page 7

• Manufacturer Part Number: DS1347
• Description: The DS1347 SPI-compatible real-time clock (RTC) contains a real-time clock/calendar and 31 x 8 bits of static random-access memory (SRAM)
• Manufacturer: Maxim

The DS1347 is a real-time clock/calendar with an SPI-
compatible interface and 31 x 8 bits of SRAM. It pro-
vides seconds, minutes, hours, day of the week, date of
the month, month, and year information, held in seven
8-bit timekeeping registers (see the Functional
Table 1. Register Map
ADDRESS
0Bh
0Dh
1Bh
1Dh
4Bh
4Dh
Low-Current, SPI-Compatible Real-Time Clock
01h
03h
05h
07h
09h
0Fh
13h
15h
17h
19h
1Fh
21h
23h
25h
3Fh
41h
43h
45h
47h
49h
4Fh
51h
53h
55h
12/
12/
BIT 7
ALM
OUT
WP
X
X
X
X
X
X
X
X
X
X
X
0
0
0
0
0
0
0
0
0
0
_______________________________________________________________________________________
Detailed Description
DOSF
BIT 6
YEAR
X
X
X
X
X
X
X
X
X
X
X
0
0
0
0
0
1000 YEAR
0
0
0
0
10 YEAR
10 YEAR
10 SECONDS
10 SECONDS
10 MINUTES
10 MINUTES
See the Data Input (Burst Write) section.
20 HR
20 HR
EGFIL
BIT 5
DAY
0
0
0
0
0
X
X
X
X
X
X
X
X
X
X
X
/PM
/PM
10 DATE
10 DATE
MONTH
10 MO
10 MO
10 HR
10 HR
BIT 4
X
X
X
X
X
X
X
X
X
X
X
0
0
0
0
DATE
BIT 3
X
X
X
X
X
X
X
X
X
X
X
0
0
0
0
HOUR
BIT 2
Diagram ). An on-chip 32.768kHz oscillator circuit
requires only a single external crystal to operate. Table
1 shows the device’s register addresses and defini-
tions. Time and calendar data are stored in the regis-
ters in binary-coded decimal (BCD) format. A polled
alarm function is included for scheduled timing of user-
defined times or intervals.
OSF
0
X
X
X
X
X
X
X
X
X
X
X
SECONDS
100 YEAR
SECONDS
MINUTES
MINUTES
MONTH
MONTH
HOURS
HOUR
DATE
DATE
YEAR
YEAR
MINUTE SECOND
BIT 1
DAY
DAY
0
1
X
X
X
X
X
X
X
X
X
X
X
BIT 0
ID
1
X
X
X
X
X
X
X
X
X
X
X
Alarm Seconds
Alarm Minutes
Configuration
Alarm Month
Alarm Hours
Clock Burst
FUNCTION
Alarm Date
Alarm Year
Alarm Day
Seconds
Minutes
RAM 10
Century
Control
RAM 0
RAM 1
RAM 2
RAM 3
RAM 4
RAM 5
RAM 6
RAM 7
RAM 8
RAM 9
Month
Status
Hours
Alarm
Date
Year
Day
1–12 +
1–12+
00h or 81h
00h–7Fh
03h–E7h
00h–FFh
00h–FFh
00h–FFh
00h–FFh
00h–FFh
00h–FFh
00h–FFh
00h–FFh
00h–FFh
00h–FFh
00h–FFh
RANGE
00–59
00–59
00–23
01–31
01–12
00–99
00–99
00–59
00–59
00–23
00–99
1–31
1–12
1–7
1–7
—
/PM
/PM
7