DS1624(2015) Ver la hoja de datos (PDF) - Maxim Integrated
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DS1624 Datasheet PDF : 14 Pages
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DS1624
Digital Thermometer and Memory
Slave Address
A control byte is the first byte received following the
START condition from the master device. The control byte
consists of a four bit control code; for the DS1624, this
is set as 1001 binary for read and write operations. The
next three bits of the control byte are the device select
bits (A2, A1, A0). They are used by the master device to
select which of eight devices are to be accessed. These
bits are in effect the three least significant bits of the slave
address. The last bit of the control byte (R/W) defines
the operation to be performed. When set to a “1”, a read
operation is selected, when set to a “0”, a write operation
is selected. Following the START condition the DS1624
monitors the SDA bus checking the device type identifier
being transmitted. Upon receiving the 1001 code and
appropriate device select bits, the slave device outputs an
acknowledge signal on the SDA line.
Measuring Temperature
Figure 1 shows a block diagram of the DS1624. The
DS1624 measures the temperature using a bandgap-
based temperature sensor. A delta-sigma analog-to-digital
(ADC) converts the temperature to a 12-bit digital value
that is calibrated in °C; for °F applications a lookup table
or conversion routine must be used. Throughout this data
sheet the term “conversion” is used to refer to the entire
temperature measurement and ADC sequence.
The temperature reading is stored as a 16-bit two’s
complement number in the 2-byte temperature register as
shown in Figure 4.
Since data is transmitted over the 2-wire bus MSB first,
temperature data can be written to/read from the DS1624
as either a single byte (with temperature resolution of
1°C) or as 2 bytes, the second byte containing the value
of the four least significant bits of the temperature reading
as shown in Figure 4. Note that the remaining 4 bits of this
byte are set to all zeros.
WRITE TO DS1624
BUS ACTIVITY:
MASTER
SDA LINE
BUS ACTIVITY
READ FROM DS1624
BUS ACTIVITY:
MASTER
SDA LINE
BUS ACTIVITY
CONTROL
BYTE
CONTROL
BYTE
COMMAND
PROTOCOL
COMMAND
PROTOCOL
Figure 3. 2-Wire Serial Communication with DS1624
DATA
BYTE
CONTROL
BYTE
DATA
BYTE 0
DATA
BYTE 1
MS BYTE
LS BYTE
BIT 15
S
BIT 7
2-1
BIT 14
26
BIT 6
2-2
Figure 4. Temperature Register Format
BIT 13
25
BIT 5
2-3
BIT 12
24
BIT 4
2-4
BIT 11
23
BIT 3
0
BIT 10
22
BIT 2
0
BIT 9
21
BIT 1
0
BIT 8
20
BIT 0
0
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