Dallas DS1726U High-precision 3-wire digital thermometer and thermostat Datasheet

DS1626/DS1726
High-Precision 3-Wire Digital
Thermometer and Thermostat
www.maxim-ic.com
FEATURES
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PIN CONFIGURATION
Temperature Measurements Require No
External Components
Measure Temperatures from -55°C to +125°C
(-67°F to +257°F)
DS1626: ±0.5°C Accuracy from 0°C to
+70°C
DS1726: ±1°C Accuracy from -10°C to
+85°C
Output Resolution is User-Selectable to 9, 10,
11, or 12 Bits
Wide Power-Supply Range (2.7V to 5.5V)
Convert Temperature to Digital Word in
750ms (max)
Stand-Alone Thermostat Capability
Thermostatic Settings are User-Definable and
Nonvolatile (NV)
Data is Read/Written Through a 3-Wire Serial
Interface
Available in 8-Pin mMAX/mSOP Package
8
VDD
2
7
THIGH
3
6
TLOW
4
5
TCOM
DQ
1
CLK/CNV
RST
GND
mSOP
(DS1626U, DS1726U)
See Table 1 for Ordering Information
See Table 2 for Pin Descriptions
APPLICATIONS
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Thermostatic Controls
Industrial Controls
Consumer Products
Any Space-Constrained Thermally Sensitive
Application
DESCRIPTION
The DS1626 and DS1726 digital thermometers/thermostats provide temperature measurements and standalone thermostat capability over a -55°C to +125°C range. The DS1626 offers ±0.5°C accuracy from 0°C to
+70°C and the DS1726 has ±1°C accuracy from -10°C to +85°C. The resolution of the measured
temperature is user-selectable from 9 to 12 bits. Communication with the DS1626 and DS1726 is achieved
through a 3-wire serial bus.
The DS1626 and DS1726 offer thermostatic functionality with three dedicated thermostat outputs (THIGH,
TLOW, and TCOM), and over-temperature (TH) and under-temperature (TL) user-programmable thresholds
stored in on-chip EEPROM. For stand-alone thermostat operation, TH and TL can be programmed prior to
installation, and the DS1626/DS1726 can be configured to automatically begin taking temperature
measurements at power-up.
Pin descriptions for the DS1626 and DS1726 are provided in Table 2 and user-accessible registers are
summarized in Table 3. A functional diagram is shown in Figure 1.
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06/10/03
DS1626/DS1726
ORDERING INFORMATION
PART
DS1626U
DS1626U/T&R
DS1726U
DS1726U/T&R
PACKAGE MARKING
D1626
D1626
D1726
D1726
DESCRIPTION
8-Pin mSOP
8-Pin mSOP, 3000-Piece Tape-and-Reel
8-Pin mSOP
8-Pin mSOP, 3000-Piece Tape-and-Reel
Table 2. DETAILED PIN DESCRIPTION
PIN
1
SYMBOL
DQ
2
CLK/CNV
3
4
5
6
7
8
RST
GND
TCOM
TLOW
THIGH
VDD
FUNCTION
Data Input/Output Pin (Tri-State) for 3-Wire Serial Communication
Clock Input Pin for 3-Wire Serial Communication. Controls temperature
measurements when the DS1626/DS1726 is configured as a stand-alone thermostat
Reset Input Pin for 3-Wire Serial Communication
Ground Pin
Thermostat Output Pin (Push-Pull) with Programmable Hysteresis
Thermostat Output Pin (Push-Pull) with TL Trip Point
Thermostat Output Pin (Push-Pull) with TH Trip Point
Supply Voltage. +2.7V to +5.5V Input Power Pin
Table 3. DS1626/DS1726 REGISTER SUMMARY
REGISTER NAME
(USER ACCESS)
Temperature
(Read Only)
SIZE
MEMORY
TYPE
12 Bits
SRAM
TH
(Read/Write)
12 Bits
EEPROM
TL
(Read/Write)
12 Bits
EEPROM
Configuration
(Various Bits are
Read/Write and Read
Only—See Table 5)
1 Byte
SRAM and
EEPROM
REGISTER CONTENTS
AND POWER-UP/POR STATE
Measured Temperature (Two’s Complement)
Power-Up/POR State: -60ºC (1100 0100 0000)
Upper Alarm Trip Point (Two’s Complement)
Power-Up/POR State: User-Defined.
Initial State from Factory: +15°C (0000 1111 0000)
Lower Alarm Trip Point (Two’s Complement)
Power-Up/POR State: User-Defined.
Initial State from Factory: +10°C (0000 1010 0000)
Configuration and Status Information (Unsigned)
4MSbs = SRAM and 4LSbs = EEPROM
Power-Up/POR State: 1000XXXX (XXXX = UserDefined)
Figure 1. DS1626/DS1726 FUNCTIONAL DIAGRAM
VDD
CONFIGURATION REGISTER AND CONTROL LOGIC
GND
TEMPERATURE SENSOR AND DS ADC
ADDRESS
and
I/O CONTROL
CLK/CNV
SDA
RST
TEMPERATURE REGISTER
TH REGISTER
TL REGISTER
2 of 13
DIGITAL
COMPARATOR/LOGIC
TCOM
THIGH
TLOW
DS1626/DS1726
ABSOLUTE MAXIMUM RATINGS*
Voltage on Any Pin Relative to Ground
Operating Temperature Range
Storage Temperature Range
Solder Dip Temperature (10s)
Reflow Oven Temperature
-0.5V to +6.0V
-55°C to +125°C
-55°C to +125°C
+260°C
+220°C
* These are stress ratings only and functional operation of the device at these or any other conditions
above those indicated in the operation sections of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods of time may affect reliability.
DC ELECTRICAL CHARACTERISTICS
(VDD = 2.7V to 5.5V; TA = -55°C to +125°C.)
PARAMETER
Supply Voltage
DS1626
Thermometer Error
(Note 2)
DS1726
Thermometer Error
(Note 2)
Low-Level Input
Voltage
High-Level Input
Voltage
Input Current each
Input Pin
Active Supply
Current (Note 3)
Input Resistance
Standby Supply
Current
THIGH, TLOW,
TCOM, DQ Output
Logic Voltages
(Note 1)
Thermal Drift
SYMBOL
VDD
CONDITIONS
(Note 1)
0°C to +70°C,
3.0V £ VDD £ 5.5V
0°C to +70°C,
2.7V £ VDD < 3.0V
-55°C to +125°C
-10°C to +85°C,
3.0V £ VDD £ 5.5V
-10°C to +85°C,
2.7V £ VDD < 3.0V
-55°C to +125°C
MIN
2.7
VIL
(Note 1)
-0.5
0.3 x VDD
V
VIH
(Note 1)
0.7 x VDD
VDD + 0.3
V
-10
+10
µA
TERR
TERR
0.4 < VI/O < 0.9 x VDD
IDD
RI
Temperature conversion
-55°C to +85°C
Temperature conversion
+85°C to +125°C
E2 write
RST to GND
DQ, CLK to VDD
ISTBY
0°C to +70°C (Note 3)
VOH
1mA source current
VOL
4mA sink current
(Note 4)
TYP
UNITS
V
±0.5
±1.25
°C
±2
±1
±1.5
°C
±2
1
mA
1.25
400
1
µA
MW
1.5
µA
2.4
0.4
±0.2
3 of 13
MAX
5.5
V
°C
DS1626/DS1726
EEPROM AC ELECTRICAL CHARACTERISTICS
(VDD = 2.7V to 5.5V; TA = -55°C to +125°C.)
PARAMETER
EEPROM Write Cycle Time
EEPROM Writes
EEPROM Data Retention
SYMBOL CONDITIONS
twr
NEEWR
-55°C to +55°C
tEEDR
-55°C to +55°C
MIN
TYP
4
MAX
10
50k
10
UNITS
ms
Writes
Years
AC ELECTRICAL CHARACTERISTICS
(VDD = 2.7V to 5.5V; TA = -55°C to +125°C.)
PARAMETER
Temperature Conversion Time
Data In to Clock Setup
Clock to Data In Hold
Clock to Data Out Delay
Clock Low/High Time
Clock Frequency
Clock Rise/Fall Time
RST to Clock Setup
Clock to RST Hold
RST Inactive Time
Clock High to I/O Hi-Z
RST Low to I/O Hi-Z
CNV Pulse Width
I/O Capacitance
Input Capacitance
SYMBOL
tTC
tDC
tCDH
tCDD
tCL, tCH
fCLK
tR , tF
tRC
tCRH
tRI
tCDZ
tRDZ
tCNV
CI/O
CI
CONDITIONS
9-bit
10-bit
11-bit
12-bit
(Note 5)
(Note 5)
(Notes 5, 6)
(Note 5)
(Note 5)
(Note 5)
(Note 5)
(Note 5)
(Note 7)
(Note 5)
(Note 5)
(Note 8)
MIN
TYP
MAX
93.75
187.5
375
750
35
40
150
285
0
1.75
500
100
40
125
50
50
500ms
250ns
10
5
UNITS
ms
ns
ns
ns
ns
MHz
ns
ns
ns
ns
ns
ns
pF
pF
NOTES:
1)
2)
3)
4)
5)
6)
7)
8)
All voltages are referenced to ground.
See Figure 2 for TYPICAL OPERATING CURVES.
ISTBY, IDD specified with DQ, CLK/CNV = VDD and RST = GND.
Drift data is based on a 1000hr stress test at +125°C with VDD = 5.5V.
See Timing Diagrams in Figure 3. All timing is referenced to 0.7 x VDD and 0.3 x VDD.
Load capacitance = 50pF.
tRI must be 10ms minimum following any write command that involves the E2 memory.
250ns is the guaranteed minimum pulse width for a conversion to start, however, a smaller pulse
width may start a conversion.
4 of 13
DS1626/DS1726
Figure 2. TYPICAL OPERATING CURVES
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1
DS1726
ERROR (°C)
ERROR °C
DS1626
+3s
MEAN
-3s
0
10
20
30
40
50
60
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1
+3s
MEAN
-3s
-10
70
0
10
20
30
40
50
60
70
80
REFERENCE TEMPERATURE (°C)
REFERENCE TEMPERATURE (°C)
Figure 3. TIMING DIAGRAMS
a) Read Timing
tCRH
tRC
b) Write Timing
tRI
tCRH
tRC
5 of 13
DS1626/DS1726
OPERATION—MEASURING TEMPERATURE
The DS1626/DS1726 measure temperature using a bandgap-based temperature sensor. A delta-sigma
analog-to-digital converter (ADC) converts the measured temperature to a digital value that is
calibrated in degrees centigrade; for Fahrenheit applications a lookup table or conversion routine must
be used. Communication with the DS1626/DS1726 is achieved through a 3-wire serial interface, and
all data is transmitted LSb first.
The DS1626/DS1726 can be programmed to take continuous temperature measurements (continuous
conversion mode) or to take single temperature measurements on command (one-shot mode). The
measurement mode is programmed by the 1SHOT bit in the configuration register as explained in the
CONFIGURATION REGISTER section of this data sheet. The 1SHOT bit is stored in EEPROM, so it
can be programmed prior to installation if desired. In continuous conversion mode, when a Start
Convert T command is issued the DS1626/DS1726 perform consecutive temperature measurements
until a Stop Convert T command is issued. In one-shot mode, the Start Convert T command causes one
temperature measurement to be taken and then the DS1626/DS1726 return to a low-power idle state.
The resolution of the DS1626/DS1726 digital temperature data is user-configurable to 9, 10, 11, or 12
bits, corresponding to temperature increments of 0.5°C, 0.25°C, 0.125°C, and 0.0625°C, respectively.
The resolution is set by the EEPROM R0 and R1 bits in the configuration register. Note that the
conversion time doubles for each additional bit of resolution.
After each temperature measurement and analog-to-digital conversion, the DS1626/DS1726 store the
measured temperature as a two’s complement number in the 12-bit temperature register (see Figure 4).
The sign bit (S) indicates if the temperature is positive or negative: for positive numbers S = 0 and for
negative numbers S = 1. The Read Temperature command provides user access to the temperature
register.
When the DS1626/DS1726 are configured for 12-bit resolution, all 12 bits of the temperature register
will contain temperature data. For 11-bit resolution, the 11 MSbs (bits 11 through 1) of the temperature
register will contain data and bit 0 will read out as 0. Likewise, for 10-bit resolution, the 10 MSbs (bits
11 through 2) will contain data, and for 9-bit the 9 MSbs (bits 11 through 3) will contain data, and all
unused LSbs will contain 0s. Since the DS1626/DS1726 transmit data LSb first, when reading data
from the temperature register, all 12 bits must be read in order to receive all MSbs of the measured
data, regardless of the conversion resolution. Table 4 gives examples of 12-bit resolution digital output
data and the corresponding temperatures.
Figure 4. TEMPERATURE, TH, and TL REGISTER FORMAT
bit 11
S
bit 10
2
6
bit 19
2
5
bit 8
2
4
bit 7
2
3
bit 6
2
2
bit 5
2
1
bit 4
0
2
6 of 13
bit 3
2
-1
bit 2
2
-2
bit 1
2
-3
bit 0
2-4
DS1626/DS1726
Table 4. 12-BIT RESOLUTION TEMPERATURE/DATA RELATIONSHIP
TEMPERATURE
(°C)
+125
+25.0625
+10.125
+0.5
0
-0.5
-10.125
-25.0625
-55
DIGITAL OUTPUT
(BINARY)
DIGITAL OUTPUT
(HEX)
0111 1101 0000
0001 1001 0001
0000 1010 0010
0000 0000 1000
0000 0000 0000
1111 1111 1000
1111 0101 1110
1110 0110 1111
1100 1001 0000
7D0h
191h
0A2h
008h
000h
FF8h
F5Eh
E6Fh
C90h
OPERATION—THERMOSTAT FUNCTION
The DS1626/DS1726 thermostat outputs (THIGH, TLOW, and TCOM) are updated after every temperature
conversion and remain at the updated values until the next conversion completes. THIGH is asserted
when the measured temperature is higher than or equal to the value stored in the TH register, and TLOW
is asserted when the temperature is equal to or falls below the value in the TL register (see Figure 5).
TCOM uses both TH and TL to provide programmable hysteresis: when the measured temperature equals
or exceeds TH, TCOM is asserted and it remains asserted until the temperature falls to a value equal to or
below TL. All three thermostat outputs are active-high outputs.
The Write TH and Write TL commands are used to program the 12-bit TH and TL registers with userdefined two’s complement values. The MSb (bit 11) of each register contains the two’s complement
sign bit (S). For the TCOM thermostat output to function correctly, the TL value must be less than the TH
value. Any unused LSbs in the TH and TL registers are forced to 0 regardless of the data written to
those bits. The unused LSbs are determined by the conversion resolution set by R1 and R0 in the
configuration register. Therefore, for 9-bit conversions bits 2 through 0 will be 0, for 10-bit
conversions bit 1 and bit 0 will be 0, and for 11-bit conversions bit 0 will be 0. All bits are used for 12bit conversions, so no bits are forced to 0. However, regardless of the conversion resolution, when
writing to TH or TL at least 12 bits must be sent following the Write TH or Write TL commands. The
reason is that data written to TH and TL is not saved to EEPROM until the DS1626/DS1726 have
received 12 bits, so if the operation is terminated before 12 bits have been received, the data will be
lost. Any additional bits sent after the first twelve are ignored (e.g., if two 8-bit words are written).
Another DS1626/DS1726 thermostat feature is the temperature-high flag (THF) and temperature-low
flag (TLF) in the configuration register. These bits provide a record of whether the temperature has
been greater than or equal to TH or less than or equal to TL at any time since the DS1626/DS1726 were
powered up. If the temperature is greater than or equal to the TH register value, the THF bit in the
configuration register will be set to 1. If the temperature is less than or equal to the TL register value,
the TLF bit in the configuration register will be set to 1. Once THF and/or TLF has been set, it will
remain set until the user overwrites it with a 0 or until the power is cycled.
7 of 13
DS1626/DS1726
CPU BIT AND STAND-ALONE THERMOSTAT OPERATION
In stand-alone thermostat mode, DS1626/DS1726 thermostat functionality can be used without
requiring a microcontroller to start/stop temperature conversions. The CPU bit in the configuration
register determines if stand-alone mode is enabled.
When CPU = 1 stand-alone mode is disabled, and the only way to start/stop temperature conversions is
by using a microcontroller to transmit Start Convert T and Stop Convert T commands, respectively.
Stand-alone mode is enabled when CPU = 0. In this mode, when RST = 0 the CLK/CNV pin operates
as a control signal to start and stop temperature measurements. Driving CLK/CNV low initiates
continuous temperature conversions that will continue until CLK/CNV is brought high again. If the
CLK/CNV pin is driven low and then returned to a high state in less than 10ms, only one temperature
conversion will be performed after which the DS1626/DS1726 will return to a low-power idle state
(i.e., one-shot operation). Note that when stand-alone mode is enabled, the 1SHOT bit in the
configuration register is ignored, and only the CLK/CNV signal determines whether continuous or
one-shot conversions take place.
Since TH, TL, and the CPU bit are stored in EEPROM, the DS1626/DS1726 can be preprogrammed for
stand-alone operation. If desired, the CLK/CNV and RST pin can be connected to GND so the
DS1626/DS1726 will automatically begin taking temperature measurements at power-up
Normal bus communication with the DS1626/DS1726 can still take place in stand-alone mode when
RST = 1. When communication is initiated, stand-alone conversions are automatically halted. If during
the bus communication continuous temperature conversions are started using the Start Convert T
command, they can only be stopped by issuing a Stop Convert T command.
8 of 13
DS1626/DS1726
Figure 5. THERMOSTAT OUTPUT OPERATION
TH
TL
LOGIC 1
TCOM
LOGIC 0
TEMP
LOGIC 1
THIGH
LOGIC 0
TEMP
LOGIC 1
TLOW
LOGIC 0
TEMP
CONFIGURATION REGISTER
The configuration register allows the user to customize the DS1626/DS1726 conversion and
thermostat options. It also provides information to the user about conversion status, EEPROM activity,
and thermostat activity. The configuration register is arranged as shown in Figure 6 and detailed
descriptions of each bit are provided in Table 5. This register can be accessed using the Read Config
and Write Config commands. Note that the R1, R0, CPU, and 1SHOT bits are stored in EEPROM and
all other configuration register bits are SRAM.
Figure 6. CONFIGURATION REGISTER
MSb
bit 6
bit 5
bit 4
bit 3
bit 2
DONE
THF
TLF
NVB
R1*
R0*
*NV (EEPROM)
9 of 13
bit 1
LSb
CPU* 1SHOT*
DS1626/DS1726
Table 5. CONFIGURATION REGISTER BIT DESCRIPTIONS
BIT NAME
(USER ACCESS)
DONE
(Read Only)
THF
(Read/Write)
TLF
(Read/Write)
NVB
(Read Only)
R1*
(Read/Write)
R0*
(Read/Write)
CPU*
(Read/Write)
1SHOT*
(Read/Write)
FUNCTIONAL DESCRIPTION
Power-up state = 1.
DONE = 0. Temperature conversion is in progress.
DONE = 1. Temperature conversion is complete.
Power-up state = 0.
THF = 1. The measured temperature has reached or exceeded the value stored in
the TH register. THF will remain a 1 until it is overwritten with a 0 by the user,
the power is cycled, or a Software POR command is issued.
Power-up state = 0.
TLF = 1. The measured temperature has equaled or dropped below the value
stored in the TL register. TLF will remain a 1 until it is overwritten with a 0 by
the user, the power is cycled, or a Software POR command is issued.
Power-up state = 0.
NVB = 1. Write to an E2 memory cell is in progress.
NVB = 0. NV memory is not busy.
Power-up state = last value written to this bit.
Sets conversion resolution (see Table 6).
Initial state from factory = 1.
Power-up state = last value written to this bit.
Sets conversion resolution (see Table 6).
Initial state from factory = 1.
Power-up state = last value written to this bit.
CPU = 1. Stand-alone mode is disabled.
CPU = 0. Stand-alone mode is enabled when RST = 0. See CPU BIT AND
STAND-ALONE THERMOSTAT OPERATION section for more information.
Initial state from factory = 0.
Power-up state = last value written to this bit.
1SHOT = 1: One-Shot Mode. The Start Convert T command initiates a single
temperature conversion and then the device goes into a low-power standby state.
1SHOT = 0: Continuous Conversion Mode. The Start Convert T command
initiates continuous temperature conversions.
Initial state from factory = 0.
*NV (EEPROM)
Table 6. RESOLUTION CONFIGURATION
R1
R0
RESOLUTION
0
0
1
1
0
1
0
1
9-bit
10-bit
11-bit
12-bit
10 of 13
CONVERSION
TIME (MAX)
93.75ms
187.5ms
375ms
750ms
DS1626/DS1726
3-WIRE SERIAL DATA BUS
The 3-wire bus consists of three signals: RST (reset—active low), CLK (clock), and DQ (data). 3-wire
communication is controlled by the RST signal, which functions as “chip select” signal. All data is
transferred LSb first over the 3-wire bus. All communication with the DS1626/DS1726 is initiated by
driving RST high. Driving RST low terminates communications and causes DQ to go to a highimpedance state. Note that RST must be toggled low after every communication sequence to ensure
that subsequent commands are recognized by the DS1626/DS1726.
When writing to the DS1626/DS1726, data must be valid during the rising edge of CLK. During read
operations the DS1626/DS1726 output data on DQ on the falling edge of CLK and the data remains
valid through the following rising edge, at which time the DQ pin becomes high impedance until the
next falling edge.
To communicate with the DS1626/DS1726, the master must first drive RST high and then begin
generating the CLK signal while transmitting the desired DS1626/DS1726 command byte. If the
command is a Start Convert T, Stop Convert T, or Software POR command, the transaction is finished
when the last bit of the command has been sent. Figure 7a illustrates a Start Convert T command
sequence.
When writing to the DS1626/DS1726, the master must begin transmitting data during the clock cycle
immediately following the command byte. The DS1626/DS1726 will save only the number of data bits
needed for the specific transaction. For example, for the Write TH or Write TL commands, after
twelve bits of data have been transmitted by the master, the DS1626/DS1726 will ignore any
subsequent data transmitted before RST goes low. Thus, if data is being transmitted in byte-length
segments, the DS1626/DS1726 will load the first twelve bits into the TH/TL register, and the next four
bits will be ignored. On the other hand, it is necessary to transmit at least the required number of bits
for the requested transaction (i.e., 12-bits to TH/TL or 8-bits to the configuration register), because the
DS1626/DS1726 will not save data until the expected number of bits have been received. Write TH
and Write TL sequences are illustrated in Figure 7b and a Write Config sequence is shown in Figure
7c. Note that these figures assume byte-wide data transfers.
When reading data from the DS1626/DS1726, the DS1626/DS1726 will begin sending data during the
clock cycle immediately following the command byte. After the last data byte has been sent, the
DS1626/DS1726 will transmit a 0 during each subsequent clock until RST goes low. Figure 7d
illustrates a Read Temperature sequence and a Read Config transaction is shown in Figure 7e. The
sequence for reading the TH or TL registers is the same as the Read Temp transaction in Figure 7d
except that the Read TH or Read TL command is used.
11 of 13
DS1626/DS1726
Figure 7. 3-WIRE COMMUNICATION
a) Start Temperature Conversion
RST
CLK
DQ
1
0
0
0
1
1
0
0
Start Convert T [51h] Command
b) Write to the TH/TL Registers
×××
RST
CLK
DQ
×××
C0
C1
0
0
0
0
0
0
D0
D1
D2
Write TH [01h] or TL [02h] Command
D3
D4
D5
D6
D7
D8
D9
D10 D11
TH or TL Data from Master
c) Write to the Configuration Register
RST
CLK
DQ
0
0
1
1
0
0
0
0
D0
Write Config [0Ch] Command
D1
D3
D2
D4
D5
D6
D7
Configuration Reg. Data from Master
d) Read from the Temperature Register
×××
RST
CLK
1
DQ
0
1
0
1
0
1
0
D0
1
D1
Read Temperature [AAh] Command
D2
D3
D4
D5
D6
D7
D8
D9
D10
D11
Temperature Data from DS1626/DS1726
e) Read from the Configuration Register
RST
CLK
DQ
0
0
1
1
0
1
0
Read Config [ACh] Command
1
D0
D1
D2
D3
D4
D5
D6
D7
Configuration Reg. Data from DS1626/DS1726
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0
0
0
×××
×××
DS1626/DS1726
DS1626/DS1726 COMMAND SET
The DS1626/DS1726 command set is detailed below:
Start Convert T
51h 0101 0001
Initiates temperature conversions. If the DS1626/DS1726 are in one-shot mode (1SHOT = 1), only one
conversion will be performed. If the devices are in continuous mode (1SHOT = 0), continuous
conversions will be performed until a Stop Convert T command is issued.
Stop Convert T
22h 0010 0010
Stops temperature conversions when the devices are in continuous conversion mode (1SHOT = 0).
Read Temperature
AAh 1010 1010
Reads the last converted temperature value from the temperature register.
Read TH
A1h 1010 0001
Reads the 12-bit TH register.
Read TL
A2h 1010 0010
Reads the 12-bit TL register.
Write TH*
01h 0000 0001
Writes the 12-bit TH register.
Write TL*
02h 0000 0010
Writes the 12-bit TL register.
Read Config
ACh 1010 1100
Reads the 1-byte configuration register.
Write Config*
0Ch 0000 1100
Writes the 1-byte configuration register.
Software POR
54h 0101 0100
Initiates a software power-on reset (POR), which stops temperature conversions and resets all registers
and logic to their power-up states. The software POR allows the user to simulate cycling the power
without actually powering down the device.
*After issuing a write command, no further writes should be requested for at least 10ms due to the
EEPROM write cycle time.
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