DS1346 Datasheet, PDF (12/17 Pages) Maxim Integrated Products – Low-Current, SPI-Compatible Real-Time Clocks

Low-Current, SPI-Compatible Real-Time Clocks
BIT 7
0
0
BIT 6
1
BIT 5
10 MINUTES
1
BIT 4
1
BIT 3
1
Alarm Minutes Register (1Bh)
BIT 2
BIT 1
MINUTES
1
1
BIT 0
1
BIT 7
12/24
1
BIT 6
0
0
BIT 5
AM/PM
20 HR
1
BIT 4
10 HR
1
BIT 3
1
Alarm Hours Register (1Dh)
BIT 2
BIT 1
BIT 0
HOURS
1
1
1
BIT 7
0
0
BIT 6
0
0
BIT 5
BIT 4
10 DATE
1
1
BIT 3
1
Alarm Date Register (1Fh)
BIT 2
1
DATE
BIT 1
1
BIT 0
1
BIT 7
0
0
BIT 6
0
0
BIT 5
0
0
BIT 4
10 MO
1
BIT 3
1
Alarm Month Register (21h)
BIT 2
BIT 1
MONTH
1
1
BIT 0
1
BIT 7
0
0
BIT 6
0
0
BIT 5
0
0
BIT 4
0
0
BIT 3
0
0
Alarm Day Register (23h)
BIT 2
1
BIT 1
DAY
1
BIT 0
1
BIT 7
1
BIT 6
BIT 5
10 YEAR
1
1
BIT 4
1
BIT 3
1
Alarm Year Register (25h)
BIT 2
1
YEAR
BIT 1
1
BIT 0
1
SPI-Compatible Serial Interface
Interface the devices with a microcontroller using a
serial, 4-wire, SPI interface. SPI is a synchronous bus
for address and data transfer, and is used with
Motorola or other microcontrollers that have an SPI
port. Four connections are required for the interface:
DOUT (serial-data out); DIN (serial-data in); SCLK (ser-
ial clock); and CS (chip select). In an SPI application,
the devices act as a slave device and the microcon-
troller acts as the master. CS is asserted low by the
microcontroller to initiate a transfer, and deasserted
high to terminate a transfer. DIN transfers input data
from the microcontroller to the devices. DOUT trans-
fers output data from the devices to the microcon-
troller. A shift clock, SCLK, is used to synchronize data
movement between the microcontroller and the
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