DS1347_1202 Datasheet, PDF (7/17 Pages) Maxim Integrated Products – Low-Current, SPI-Compatible Real-Time Clock

Low-Current, SPI-Compatible Real-Time Clock
Detailed Description
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
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.
Table 1. Register Map
ADDRESS
01h
03h
05h
07h
09h
0Bh
0Dh
0Fh
13h
15h
17h
19h
1Bh
1Dh
1Fh
21h
23h
25h
3Fh
41h
43h
45h
47h
49h
4Bh
4Dh
4Fh
51h
53h
55h
BIT 7
0
ALM
OUT
12/24
0
0
0
WP
0
EOSC
0
0
12/24
0
0
0
X
X
X
X
X
X
X
X
X
X
X
BIT 6 BIT 5 BIT 4
10 SECONDS
BIT 3
BIT 2 BIT 1
SECONDS
BIT 0
FUNCTION
Seconds
RANGE
00–59
10 MINUTES
MINUTES
Minutes
00–59
AM/PM
0
10 HR
20 HR
0
10 DATE
0
0
10 MO
0
0
0
0
10 YEAR
0
0
0
0
1000 YEAR
HOUR
DATE
MONTH
DAY
YEAR
0
0
ID
100 YEAR
YEAR DAY MONTH DATE HOUR MINUTE SECOND
DOSF EGFIL
0
0
OSF
1
1
10 SECONDS
SECONDS
10 MINUTES
MINUTES
AM/PM
0
10 HR
20 HR
HOURS
0
10 DATE
DATE
0
0
10 MO
MONTH
0
0
0
0
DAY
10 YEAR
YEAR
See the Data Input (Burst Write) section.
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Hours
Date
Month
Day
Year
Control
Century
Alarm
Configuration
Status
Alarm Seconds
Alarm Minutes
Alarm Hours
Alarm Date
Alarm Month
Alarm Day
Alarm Year
Clock Burst
RAM 0
RAM 1
RAM 2
RAM 3
RAM 4
RAM 5
RAM 6
RAM 7
RAM 8
RAM 9
RAM 10
1–12+AM/PM
00–23
01–31
01–12
1–7
00–99
00h or 81h
00–99
00h–7Fh
03h–E7h
00–59
00–59
1–12 + AM/PM
00–23
1–31
1–12
1–7
00–99
—
00h–FFh
00h–FFh
00h–FFh
00h–FFh
00h–FFh
00h–FFh
00h–FFh
00h–FFh
00h–FFh
00h–FFh
00h–FFh
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