DS1346 MAXIM [Maxim Integrated Products], DS1346 Datasheet - Page 12

• Manufacturer Part Number: DS1346
• Description: Low-Current, SPI-Compatible Real-Time Clocks
• Manufacturer: MAXIM [Maxim Integrated Products]

Low-Current, SPI-Compatible Real-Time Clocks
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,
12
BIT 7
______________________________________________________________________________________
BIT 7
BIT 7
BIT 7
BIT 7
BIT 7
12/
SPI-Compatible Serial Interface
0
0
0
0
0
0
0
0
1
1
BIT 6
BIT 6
BIT 6
BIT 6
BIT 6
BIT 6
1
0
0
0
0
0
0
1
0
0
10 YEAR
10 MINUTES
BIT 5
BIT 5
BIT 5
BIT 5
BIT 5
20 HR
BIT 5
0
0
1
1
0
0
1
1
/PM
10 DATE
10 MO
BIT 4
BIT 4
BIT 4
BIT 4
BIT 4
10 HR
BIT 4
1
1
1
0
0
1
1
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
BIT 3
BIT 3
BIT 3
BIT 3
BIT 3
BIT 3
1
1
1
0
0
1
1
BIT 2
BIT 2
BIT 2
BIT 2
BIT 2
BIT 2
Alarm Minutes Register (1Bh)
1
1
1
1
1
1
Alarm Month Register (21h)
Alarm Hours Register (1Dh)
Alarm Year Register (25h)
Alarm Date Register (1Fh)
MINUTES
MONTH
Alarm Day Register (23h)
HOURS
DATE
YEAR
BIT 1
BIT 1
BIT 1
BIT 1
BIT 1
BIT 1
DAY
1
1
1
1
1
1
BIT 0
BIT 0
BIT 0
BIT 0
BIT 0
BIT 0
1
1
1
1
1
1