dallas semiconductor DS1702K service manual
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DS1702K 2-Wire Thermal Device
Evaluation Kit
Kit Instructions and Operating Procedures
FEATURES:
· Full-Featured Evaluation Kit for the DS1702K includes
testing software for the DS1621, DS1721, DS1624,
DS1629, DS75, and DS1775 devices. The DS1702K
is comprised of five separate and unique software kits:
the DS1721K.exe (works for both the DS1621 and
DS1721), DS1624K.exe, DS1629K.exe, and the
DS75K.exe. Each software package works through the
same 2-wire DS1702K board (included in the
DS1702K kit) with jumper selections. The DS75K is
completely software compatible with the DS1775
device requirements. However, the SOT23-5 (5-pin
socket) is not provided.
TM
· Compatible with Windows
Windows NT Operating Systems.
· Complete read/write access to all registers within the
DS1621, DS1721, DS1624, DS1629, and DS75
devices.
· Measures temperatures from the full range of the
devices -55°C to +125°C. Fahrenheit equivalent is
-67°F to +257°F.
95, Windows 98, and
HARDWARE:
The 2-wire board as shown in Figure 1.0 allows the user to
test the functional capabilities of each device. The circuitry
allows the user to read the temperature, and to read and
write the appropriate registers of the socketed device.
Figure 1.0 2-Wire Board Block Diagram
· Celsius and Fahrenheit temperature reading and
charting is provided for the DS75, DS1621, and
DS1721 devices.
KIT CONTENTS:
1. Separate Programming Software on the CDROM
containing the DS1721K.exe, DS1624K.exe, DS1629K.exe
and the DS75K.exe “Setup.exe” Installers.
2. 87-1702K-000, 2-Wire Demo board.
3. Demo Kit Documentation Provided on CDROM for
each software program.
4. DS9123 Universal Brick serial port device and cable.
To use the kit, you will also need:
1. An available Serial Port to connect the DS9123
Universal Brick modular data cable.
2. Finally, you will need to provide a +2.7V to +5V
regulated power supply with banana-jack leads.
Windows is a trademark of Microsoft.
COM PORT SELECTIONS
The serial port selection can be changed by the user at
any time by changing the “Comm Port” number on the
“Select Preferences” form (see Figure 2.0). The “Select
Preferences” form resides under the “Preferences” menu.
The baud rate selection also resides on the “Select
Preferences” form.
Figure 2.0 COM Port Preferences
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USING THE DS1621/1721K EVALUATION KIT
Once the 2-wire cable is connected to the serial port, you
may then turn on the +3V to +5V regulated power supply to
power the board. Next, run the DS1721K.exe executable
to view the screen shown in Figure 3.0.
Figure 3.0 DS1621/1721K Start-Up Splash Screen
The splash screen will appear if the DS9123 module is
connected to the serial port. The evaluation board does not
need to be present to run the software.
However, upon loading the software some registers are
initialized; therefore, it is recommended that the evaluation
board be present and powered upon software startup.
Power for the DS9123 module is obtained via the serial
port. If the DS9123 module is not present, the software
will not load. The only way to escape this mode is to
reboot or Ctrl-Alt-Del to End Task. If problems occur during
the program start-up, check the DS9123 to make sure it is
properly connected. Remove and reconnect if necessary.
software is designed to initialize the DS1721 device upon
start up and to look for the device at address “000”. The
user may change the address by clicking the appropriate
address at the top of the tab. Corresponding jumpers JP1,
JP2, and JP3 or JP5, JP6, and JP7 should be in place.
When the DS1721 150mil SO is used, the device will be
placed in the OTS socket. Jumpers JP11 and JP12 will be
removed when this socket is populated with any part other
than the DS1629. JP9, JP10, and JP13 will be added for
addresses other than “000”.
Figure 4.0 The Temperature Sensor Screen
Figure 5.0 DS1621 Device Access
THE TEMPERATURE SENSOR TAB
Upon successful loading of the software, the Temp. Sensor
screen as shown in Figure 4.0 should appear. The
Temperature Sensor screen is a tabbed user interface. All
functions of the device may be accessed through this
screen. The user may choose to populate the board with
either the DS1621 device or the DS1721 device. The user
may simply click the “On” button to begin immediately
reading the device temperature in both Celsius and
Fahrenheit.
As the evaluation board is designed to test no more than
two devices at a time, the user must choose which device
will be socketed. If testing the DS1621, the user may click
on the “->1621” tree-view to obtain access to all of the
DS1621 internal registers or by simply clicking on the
“1621” radio button.
Figure 5.0 illustrates the tree-view when the user clicks on
the “1621” radio button. All of the DS1621 device registers
are displayed. By clicking on each of the commands in the
tree-view, the user may execute a command such as “Start
Conversions” or read and write to specific registers. The
TEMPERATURE SENSOR ALARMS
The Temperature High and Temperature Low Flags are set
and monitored in the Configuration Register. By writing to
A1h and A2h the user may set the Temp. High and Temp.
Low registers, respectively. When either alarm flag is set
in the Configuration Register, the alarm is detected by
software and the appropriate led(s) is (are) set from blue to
red accordingly to indicate an alarm condition.
The user may click the blue Temp. High and Temp. Low
arrows on the user interface to set the limits in the
appropriate registers (see Figure 6.0). Any click on these
arrows automatically writes to the corresponding register.
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Note: The DS1621 alarm status flags (THF and TLF) are
retained in nonvolatile memory in the Configuration
Register. When these bits have been set by an alarm
condition, they can only be cleared by writing 0 to these
bits (i.e., by writing “A” to the Configuration Register).
Figure 6.0 Temperature Sensor Alarms
TEMPERATURE CHARTING
By clicking the “Chart” button next to the “On” button, the
software will begin plotting the device temperature (see
Figure 7.0). The user must click the “On” button to view
continuous real-time temperature data. Otherwise, the last
temperature reading will be plotted indefinitely. Since this
plot is performed via a dynamic reading of the device
temperature register, any changes in device temperature
will be immediately detected and plotted.
There are three scales for plotting the device temperature.
The software is set to display the “Room Temperature”
scale as the initial setting.
The “Room Temperature” scale is from +15.75°C to
+26.25°C or about +60.35°F to +79.25°F. The “Mid Scale”
and “Full Scale” settings are also available to view
variations and wider temperature extremes.
Note: If the current temperature is above +26.25°C, the
user must click the “Mid Scale” or “Full Scale” radio buttons
to see the plot. The program does not set the scale
changes automatically.
The “Chart Temp.” button can be used to clear an
existing temperature chart and to plot new temperature
data.
When the user clicks “OK” the temperature plot is
hidden, but still active. Following the initial “Chart”
command, the user will should click “Chart Temp.” to
continue to view the dynamic temperature data plot.
Figure 7.0 DS1621/1721K Temperature Charting
THE REGISTER ACCESS TAB
To view the Register Tab (see Figure 8.0) simply click on
the word “REGISTERS” at the top of the tab form. The
Register Tab provides user access to both the DS1621
and the DS1721 device internal registers.
The following list of commands are available via the
Register Tab:
1621 Start(EEh): When clicked, this command button
sends an “EEh” to the device to start temperature
conversions for the 1621 device. This must be done prior
to reading the temperature, otherwise the device will not
update temperature readings.
Stop Conversions(22h): This command is used to halt the
continuous conversion mode.
1721 Start(51h): This is the start temperature conversion
command button for the DS1721.
Write Config. Reg.(ACh): This command writes the
command code in the adjacent edit box to the configuration
register.
Read Config. Reg.(ACh): The user may read the
configuration register to determine the status of the Temp.
High and Temp. Low flags or to set the polarity of Tout as
well as monitor conversion completion. See the “Operation
And Control” section for the DS1621 and DS1721 data
sheets.
Read Temp. Loop On/Off: When clicked, the command
performs a continuous read of the temperature register, as
shown in Figure 3.0.
Write TH (A1h): This command writes the contents of the
adjacent edit boxes (two bytes) to the Temp. High register.
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The value written will set the temperature high threshold
for operation of the Tout output.
Read TH (A1h): This command allows the user to read the
contents of the Temp. High register. See “Command Set”
in the data sheets.
Write TL (A2h): This command writes the contents of the
adjacent edit boxes (two bytes) to the Temp. Low register.
The value written will set the temperature Low threshold for
operation of shutting off the Tout output.
Read TL (A2h): This command allows the user to read the
contents of the Temp. Low register. See “Command Set” in
the data sheets.
Note: For the DS1721 the Alarm LEDs are self-clearing
when the power is cycled. For the DS1621 the user must
clear the Temp. High and Temp. Low Flags in the Config.
Register to clear the Alarm LEDs.
1621 Read Counter (A8h): This command reads the value
of the counter byte from the DS1621. The DS1721 does
not have a corresponding register.
1621 Read Slope (A9h): This command reads the value of
the slope byte counter from the DS1621. The DS1721
does not have a corresponding register
DS1621 will be high. A “0” stored in this location sets the
thermostat output to an active low state. The power-up
default state is “1” (active high).
THE DEVICE APPLICATION TAB
The Device Application Tab may be accessed by clicking
“APPLICATION” at the top of the tab form.
The Device Application Tab provides a color block diagram
of the DS1721 which, at a block level, is the functional
equivalent of the DS1621. Differences between the two
devices exist in the resolution of the temperature reading,
the “Start Conversion” command, and the DS1621
provides a slope byte counter as well as an “NVB” bit in the
Configuration Register.
As shown in Figure 9.0, the Tout output can be used to
turn on an external fan (provided by the user) once the preset temperature limit has been exceeded. This output may
also be used for any number of other signaling functions to
the processor or simply be used with an LED as an On/Off
indicator, as demonstrated on the 2-wire evaluation board.
Figure 9.0 Device Application Tab
1721 Set 9 to 12-Bit Resolution: This set of commands is
controlled by writing to the R1,R0 bits in the configuration.
The DS1621 does not have corresponding bits as all
conversions have 9-bit resolution.
Figure 8.0 Register Access Tab
One-Shot Bit: This command is controlled by writing to the
Configuration Register. If 1Shot is “1”, the DS1621 or the
DS1721 will perform and store one temperature conversion
upon reception of the Start Convert T protocol. If 1 Shot is
“0”, either device will perform continuous conversions.
Set/Clear Polarity Bit: This command is controlled by
writing to the Configuration Register. If POL is “1”, the
active state of the Tcom output of either the DS1621 or the
USING THE DS1624K EVALUATION KIT
Once the 2-wire cable is connected to the serial port, you
may then turn on the +3V to +5V regulated power supply to
power the board. Next, run the DS1624K.exe executable
to view the screen shown in Figure 10.0. The splash
screen will appear if the DS9123 module is connected to
the serial port. The evaluation board does not need to be
present to run the software. However, upon loading the
software some registers are initialized, therefore it is
recommended that the evaluation board be present and
powered upon software startup. Power for the DS9123
module is obtained via the serial port. If the DS9123
module is not present, the software will not load. The
only way to escape this mode is to reboot or Ctrl-Alt-Del to
End Task. If problems occur during the program start-up,
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check the DS9123 to make sure it is properly connected.
Remove and reconnect if necessary.
Figure 10.0 DS1624K Start-up Splash Screen
THE TEMPERATURE SENSOR TAB
Upon successful loading of the software, the Temp. Sensor
screen shown in Figure 11.0 should appear. The
Temperature Sensor screen is a tabbed user interface. All
functions of the device may be accessed through this
screen. The user must populate the board with the DS1624
device in the DIP socket provided.
The user may simply click the “On” button to begin
immediately reading the device temperature in both
Celsius and Fahrenheit.
Figure 11.0 The Temperature Sensor Tab
address of the 256 bytes of EEPROM memory. These
commands are described in detail in the following
paragraphs.
Table 1.0 Command Set
THE DS1624 COMMAND SET
Read Temperature [AAh]: This command reads the last
temperature conversion result from the Thermometer
Register in the format described in the “OPERATIONMeasuring Temperature” section of the data sheet. If
one’s application can accept thermometer resolution of
only 1.0°C, the master only must read the first data byte
and follow with a NACK and STOP. For higher resolution,
both bytes must be read.
Start Convert T [EEh]: This command begins a
temperature conversion. No further data is required. In
one-shot mode, the temperature conversion will be
performed and then the DS1624 will remain idle. In
continuous mode, this command will initiate continuous
conversions.
The user may click on the “->DS1624” tree-view (see
Figure 15.0) to obtain access to all of the DS1624 internal
registers.
The software is designed to initialize the DS1624 device
upon start up and to look for the device at address “000”.
The user may change the address by clicking the
appropriate address located under the“Address” tab.
Corresponding jumpers JP1, JP2, and JP3 should be in
place.
Table 1.0 illustrates the Command Set for the four internal
device registers plus the command code for the beginning
Stop Convert T [22h]: This command stops temperature
conversion. No further data is required. This command
may be used to halt a DS1624 in continuous conversion
mode. After issuing this command, the current
temperature measurement will be completed, and then the
DS1624 will remain idle until a Start Convert T is issued to
resume conversions.
Access Memory [17h]: This command instructs the
DS1624 to access the user-EEPROM array, starting with
the specified byte address. Read/write depends upon the
state of the R/W* in the 2-wire control byte.
Access Config [ACh]: If R/W* is 0, this command causes
the next data byte value to be written into the configuration
register (see Table 2.0). If R/W* is 1, the next data byte
read is the value stored in the configuration register.
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