DS1346 Datasheet, PDF (7/17 Pages) Maxim Integrated Products – Low-Current, SPI-Compatible Real-Time Clocks

Low-Current, SPI-Compatible Real-Time Clocks
Detailed Description
The DS1346/DS1347 are real-time clocks/calendars
with an SPI-compatible interface and 31 x 8 bits of
SRAM. They provide seconds, minutes, hours, day of
the week, date of the month, month, and year informa-
tion, 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 devices’ register addresses and def-
initions. 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
HOUR
Hours
1–12+AM/PM
00–23
0
10 DATE
DATE
Date
01–31
0
0
10 MO
MONTH
Month
01–12
0
0
0
0
DAY
Day
1–7
10 YEAR
YEAR
Year
00–99
0
0
0
0
0
0
ID
Control
00h or 81h
1000 YEAR
100 YEAR
Century
00–99
YEAR
DAY
MONTH DATE
HOUR
MINUTE SECOND
Alarm
Configuration
00h–7Fh
DOSF EGFIL
0
0
OSF
1
1
Status
03h–E7h
10 SECONDS
SECONDS
Alarm Seconds
00–59
10 MINUTES
MINUTES
Alarm Minutes
00–59
AM/PM
0
10 HR
20 HR
HOURS
Alarm Hours ^{1–12 + AM/PM}
00–23
0
10 DATE
DATE
Alarm Date
1–31
0
0
10 MO
MONTH
Alarm Month
1–12
0
0
0
0
DAY
Alarm Day
1–7
10 YEAR
YEAR
Alarm Year
00–99
See the Data Input (Burst Write) section.
Clock Burst
—
X
X
X
X
X
X
X
RAM 0
00h–FFh
X
X
X
X
X
X
X
RAM 1
00h–FFh
X
X
X
X
X
X
X
RAM 2
00h–FFh
X
X
X
X
X
X
X
RAM 3
00h–FFh
X
X
X
X
X
X
X
RAM 4
00h–FFh
X
X
X
X
X
X
X
RAM 5
00h–FFh
X
X
X
X
X
X
X
RAM 6
00h–FFh
X
X
X
X
X
X
X
RAM 7
00h–FFh
X
X
X
X
X
X
X
RAM 8
00h–FFh
X
X
X
X
X
X
X
RAM 9
00h–FFh
X
X
X
X
X
X
X
RAM 10
00h–FFh
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