ETC DS1702K

DS1702K 2-Wire Thermal Device
Evaluation Kit
Kit Instructions and Operating Procedures
www.maxim-ic.com
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.
·
Compatible with WindowsTM 95, Windows 98, and
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.
·
Celsius and Fahrenheit temperature reading and
charting is provided for the DS75, DS1621, and
DS1721 devices.
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
COM PORT SELECTIONS
1. Separate Programming Software on the CDROM
containing the DS1721K.exe, DS1624K.exe, DS1629K.exe
and the DS75K.exe “Setup.exe” Installers.
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.
2. 87-1702K-000, 2-Wire Demo board.
Figure 2.0 COM Port Preferences
KIT CONTENTS:
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.
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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
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
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.
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 7.0 DS1621/1721K Temperature Charting
Figure 6.0 Temperature Sensor Alarms
THE REGISTER ACCESS TAB
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.
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
USING THE DS1624K EVALUATION KIT
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
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.
address of the 256 bytes of EEPROM memory. These
commands are described in detail in the following
paragraphs.
Figure 10.0 DS1624K Start-up Splash Screen
Table 1.0 Command Set
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
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.
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.
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.
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.
Table 1.0 illustrates the Command Set for the four internal
device registers plus the command code for the beginning
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or local printer, or saved to the “TempData.txt” text file that
will be created to reside within the program folder.
Table 2.0 DS1624 Configuration Register
Figure 13.0 Load Temperature Data
DONE = Conversion Done bit. “1”=Conversion complete,
“0”= conversion in progress.
1SHOT = Temperature Conversion Mode. If 1SHOT is
"1", the DS1624 will perform one temperature conversion
upon reception of the Start Convert T protocol. If 1SHOT
is "0", the DS1624 will continuously perform temperature
conversions and store the last completed result in the
Thermometer Register. The user has read/write access to
the nonvolatile bit, and the factory default state is “0”
(continuous mode).
THE DATABASE TABLES TAB
The DS1624K Evaluation Kit has been designed to provide
data logging and printing of both temperature and EEProm
data. There are two separate data tables provided within
the Microsoft Access database. All 256 bytes of EEProm
data are stored in the Access database table while only 60
temperature readings are captured and stored.
Figure 12.0, illustrates the listview access to both the
Configuration Register and the Command Set device
registers available through the Database Tables Tab. The
user may set or clear the 1Shot mode as well as Start and
Stop Conversions. The user may also access the 1Shot
and Done bits by simply clicking the “Read Config.
Register” command in the listview.
Figure 12.0 Database Tables Tab
Figure 14.0 illustrates the “Load EEProm Data” function of
the program. Through the File menu selection, the user
may activate the “Load EEProm Data” command function
which will automatically and immediately read real time
256 bytes (addresses 00 to FF) of EEPROM data directly
into the database table. EEPROM data can also be
directed the user’s network or local printer, or saved to the
1624EE.txt text file which will be created to reside within
the program folder.
It should be noted that the database tables are not writeenabled; therefore, they cannot be changed from the
executeable program. To change EEPROM data, the user
should make use of the “Write EEPROM Address & Data”
command in the listview.
Figure 14.0 Load EEPROM Data
Figure 13.0 illustrates the “Load Temp. Data” function of
the program. Through the File menu selection, the user
may activate the “Load Temp. Data” command function
that will automatically and immediately read real-time
temperature data directly into the database table.
Temperature data can also be directed the user’s network
The user can also read EEPROM data from the “Save
EEProm Data” menu selection (see Figure 15.0). This
selection is available under the file menu. When the user
clicks the “Save EEprom Data” button, the program begins
an immediate read of all 256 bytes of EEPROM data,
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which is sequentially read into the text window. As long as
the form is activated, the user may scroll and view the
data. However, when the form is deactivated the EEPROM
data is no longer available to view from the program. The
data is however, available in the newly created (or
updated) file called “1624EE.txt” text file, which is created
to reside alongside the program executable within the
program folder.
USING THE DS1629K 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 DS1629K.exe executable to
view the screen shown in Figure 17.0.
Figure 17.0 DS1629K Start-up Splash Screen
Figure 15.0 Save EEProm Data
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.
THE APPLICATION TAB GRAPHIC
Figure 16.0 provides a block diagram that illustrates the
internal functions of the DS1624. There are four major
functional areas of the device. In a typical application, the
2-wire circuitry will interface to a CPU. The “Address and
I/O Control” block provides read/write access to the
internal registers and the “Temperature Sensor” interfaces
to the “Status Register and Control Logic.”
The 256 bytes of user EEPROM is also illustrated in the
block diagram as “EEPROM Memory (256 bytes).” As
shown, the EEPROM is accessed independently of the
temperature registers.
Figure 16.0 Application Tab
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 unit to make sure
it is properly connected. Remove and reconnect if
necessary.
The software is designed to initialize the DS1629 device
upon start up and to look for the device at address “111”.
The device is internally hardwired to this address. Thus
only one DS1629 device can reside on a 2-wire bus to
avoid bus contention.
Add Jumpers JP11 and JP12 for the XTAL. Jumpers JP11
and JP12 will be removed when this socket is populated
with any part other than the DS1629. Jumpers JP5, JP6,
JP7, JP9, and JP10 must be removed for the DS1629.
Jumper JP13 should be added to view the open collector
output of the OSC signal at TP5. JP8 should be added and
JP4 should be removed to view the alarm output Tout at
the red banana jack J3 and TP4.
THE OPERATION TAB
Upon successful loading of the software, the “Operation”
screen as shown in Figure 18.0 should appear. The
Operation screen is a tabbed user interface.
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The user may simply click the “Read Temp” button to begin
immediately reading the device temperature in both
Celsius and Fahrenheit.
Figure 18.0 The Operation Tab
Set OSC On- Located under the “Settings” menu is the
form for the Oscillator Output. The program is designed to
initially disable the OSC output where OSC1=OSC0=0,
then set the device such that OSC1=OSC0=1. This
ensures a known state at start-up which is in agreement
with the data sheet. See Figure 5.0 Access Oscillator
output control.
Read Date- When the user clicks this button, the program
automatically reads the contents of the DS1629 clock
internal clock registers and loads this data into the day,
month, date, and year combo boxes so that the user may
view the device clock settings with the single click of a
button. The user may click the “Register Set 1” tab to view
the full date and time. Upon initial power-up the device
should read “Sunday:January:1:2000” This reading is a
clear indication that the clock has not previously been set
with the current date and time.
Write Date/Time- By clicking this button, the user can load
the current system date and time into the DS1629 internal
registers. The program will automatically select the combo
box settings and load them directly into the device internal
clock registers.
Set Alarm On- When clicked, this command button
automatically reads the adjacent combo box to determine if
the user has selected “Time”, “Thermal”, or “Either.” The
data will be “ORed” with the user OSC frequency selection.
The program then writes the appropriate selection to the
Configuration Register. If the “Time” or “Either” selection is
made, the program will automatically read the current
system time before setting a one minute alarm delay.
When the led turns from blue to green, the alarm is set and
is waiting for alarm flags to be set in the Configuration
Register. There will be a one minute delay before the
alarm is activated. When activated, the alarm LED will turn
red and the appropriate .wav sound will also be activated.
When the “Thermal” or “Either” selection is made, the data
is “ORed” with the OSC user selection before being written
to the Configuration Register. Prior to making this selection
the user should set the “Temp. High” and “Temp. Low”
limits. However, upon device initialization, the program
automatically writes “30” and “0” to the “Temp. High” and
“Temp. Low” registers, respectively. The user may test the
temperature alarm by clicking the “Set Alarm On” button,
then on the “Command “Set” tab the user may click
“Access TH”. The user may then set the “Temp. High” limit
below the current temperature to activate the alarm flags in
the Configuration Register that will in turn activate the
program alarm, thus turning the alarm LED red and
appropriate alarm sound. See Table 1.0 for Configuration
Register flags.
Read Temp- When this button is clicked, the program will
begin a continuous read of the device temperature data.
The command button reads as “Read Temp. On” during a
continuos read and “Read Temp. Off” when the
temperature function has been shut off.
CONFIGURATION REGISTER FUNCTIONS
The DS1629 internal device Configuration Register is
designed according to a two-byte structure (see Table 3).
The user may write control bits to only the MSB portion of
the register. If data is written to the LSB portion of the
register, problems occur in device interpretation of the
data. Both the MSB and LSB portions of the register
contain status information and thus can be read
simultaneously.
Table 3.0 Configuration/Status Register
1SH = Temperature Conversion Mode. If 1SHOT is "1",
the DS1629 will perform one temperature conversion upon
reception of the Start Convert T protocol. If 1SHOT is "0",
the DS1629 will continuously perform temperature
conversions and store the last completed result in the
Thermometer Register. The user has read/write access to
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the nonvolatile bit, and the factory default state is “0”
(continuous mode).
Table 6.0 OSC Frequency Configuration
POL = ALRM Polarity Bit. If POL = “1”, the active state of
the ALRM output will be high. A “0” stored in this location
sets the thermostat output to an active low state. The user
has read/write access to the nonvolatile POL bit, and the
factory default state is “0” (active low).
CNV = Power-up conversion state. If CNV=0 (factory
default), the DS1629 will automatically initiate a
temperature conversion upon power-up and supply
stability. Setting CNV=1 will cause the DS1629 to power
up in a standby state. Table 4.0 illustrates how the user
can set 1SH and CNV, depending on the power
consumption sensitivity of the application.
Table 4.0 Thermometer Power-up Modes
CAF = Clock Alarm Flag. This volatile status bit will be set
to “1” when the clock comparator is in an active state.
Once set, it will remain “1” until reset by writing to or
reading form either the clock register or clock alarm
register. A “0” in this location indicates the clock is not in
an alarm condition. This is a read- only bit.
TAF = Thermal Alarm Flag. This volatile status bit will be
set to “1” when the thermal comparator is in an active
state. Once set, it will remain “1” until measured
temperature falls below the programmed TL setting. A “0”
in this location indicates the thermometer is not in an alarm
condition. This is a read-only bit.
CAL = Clock Alarm Latch. This volatile status bit will be
set to “1” when the clock comparator becomes active.
Once set, it will remain latched until DS1629 power is
cycled. A “0” in this location indicates the clock has never
been in an alarm condition since the DS1629 was
powered-up. This is a read-only bit.
A1, A0 = Alarm Mode. Table 5.0 defines the DS1629
alarm mode, based on the settings of the A1 and A0 bits.
These bits define what event will activate the ALRM output.
The alarm flags, CAF, TAF, CAL, TAL, are functional
regardless of the state of these bits. Both locations are
read/write and nonvolatile, and the factory default state
disables the ALRM output (A1=A0=0).
Table 5.0 Alarm Mode Configuration
TAL = Thermal Alarm Latch. This volatile status bit will be
set to “1” when the thermal comparator becomes active.
Once set, it will remain latched until DS1629 power is
cycled. A “0” in this location indicates the DS1629
temperature has never exceeded TH since power-up. This
is a read-only bit.
It should be noted that the LSB of the Configuration
Register is read-only. Writing to the LSB will cause
problems with device command interpretation.
COMMAND REGISTER FUNCTIONS
OS1, OS0 = Oscillator Output Setting. Table 6.0 defines
the frequency of the OSC output, as defined by the
settings of these bits. Both locations are read/write and
nonvolatile, and the factory default state sets the OSC
frequency equal to the crystal frequency (OS1=OS0=1).
The output should be disabled if the user does not intend
to use it to reduce power consumption.
The device Command Set consists of eleven basic
commands, which be discussed in detail in the following
pages. The “Command Set” tab (see Figure 19.0) provides
access to all devices registers and commands. By clicking
on the tree-view, each command is activated.
The command set for the DS1629 is as follows:
Access Config [ACh]: If R/W* is 0, this command writes to
the configuration register. After issuing this command, the
next data byte value is to be written into the configuration
register. If R/W* is 1, the next data byte read is the value
stored in the configuration register. Because the MSB of
the configuration register is read/write and the LSB is read-
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only, the user only needs to write one byte to the register.
One or two bytes can be read.
Figure 19.0 Command Set Tab
Access Clock [C0h]: Accesses the DS1629 clock/calendar
register. If R/W* is 0 the master will write to the clock
register (set the clock). If R/W* is 1, the clock register is
read. The Clock register is addressed, so the user must
provide a beginning byte address, whether a read or write
is performed. A write to or read from this register or the
Clock Alarm register is required to clear the clock alarm
flag (CAF).
Access Clock Alarm [C7h]: Accesses the DS1629 clock
alarm register. If R/W* is 0 the master will write to the
clock alarm register (set/change the alarm). If R/W* is 1,
the clock alarm register is read. The Clock Alarm register
is addressed, so the user must provide a beginning byte
address, whether a read or write is performed. A write to
or read from this register or the Clock register is required to
clear the clock alarm flag (CAF).
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 DS1629 will remain idle. In
continuous mode, this command will initiate continuous
conversions. Issuance of this protocol may not required
upon DS1629 power-up, depending upon the state of the
CNV bit in the configuration register.
Stop Convert T [22h]: This command stops temperature
conversion. No further data is required. This command
may be used to halt a DS1629 in continuous conversion
mode.
After issuing this command, the current
temperature measurement will be completed, and then the
DS1629 will remain idle until a Start Convert T is issued to
resume conversions.
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.
Read Counter [A8h]: This command returns the 8-bit
COUNT_REMAIN value, used for high resolution
thermometer calculations.
Read Slope [A9h]: This command returns the 8-bit
COUNT_PER_C value, used for high resolution
thermometer calculations.
Access TH [A1h]: If R/W* is 0, this command writes to the
TH register. After issuing this command, the next two
bytes written to the DS1629, in the format described for
thermostat set-points, will set the high temperature
threshold for operation of the ALRM output and TAF/TAL
flags. If R/W* is 1, the value stored in this register is read
back.
Access TL [A2h]: If R/W* is 0, this command writes to the
TL register. After issuing this command, the next two
bytes written to the DS1629, in the format described for
thermostat set-points, will set the high temperature
threshold for operation of the ALRM output and TAF flag.
If R/W* is 1, the value stored in this register is read back.
Access Memory [17h]: This command instructs the
DS1629 to access the user-SRAM array, starting with the
specified byte address. Read/write depends upon the
state of the R/W* in the 2-wire control byte.
TEMPERATURE SENSOR ALARMS
The temperature high and low flags are set and monitored
in the internal device registers. By writing to address “A1h”
and address “A2h” the user may set the Temp. High
(Access TH) and Temp. Low (Access TL) registers,
respectively.
When the temperature exceeds the Access TH limit, the
“ALRM” output at pin 3 will be activated. The polarity of
the ALRM output is determined by setting “POL” bit in the
Configuration Register. IF POL = “1”, the active state of the
ALRM output will be high and the inactive or normal state
will be low. A “0” stored in the POL bit location sets the
thermostat ALRM output to an active low state and a
normal or inactive high state. The ALRM device output can
be monitored at the Tout red banana jack or at TP4 on the
2-Wire board (87-1702K-000).
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The “TAF” status bit flag is monitored by the program to
determine when the temperature high limit has been
exceeded. The program then sets the alarm LED on the
“Operation” tab and will also activate the appropriate
temperature alarm sound. The temperature low limit must
then be exceeded to remove the “TAF” flag in the
configuration status register and resume normal operation.
The user may simulate these conditions by first setting the
“Access TH” temperature below the current room
temperature. This will cause the “TAF” status flag to be set
thus initiating an alarm condition. Then, the user must set
the “Access TH” above the current room temperature
before setting the “Access TL” limit above the current room
temperature. Once this sequence of actions is complete,
the “TAF” flag will be cleared by the device and the user
should then set the “Access TL” limit below the current
room temperature to resume normal operation. Upon
power-up, the program automatically sets Access TH =
“30” and Access TL = “0”.
A read timer loop is set when the user clicks the “Read
Loop Off” button. The program activates the timer loop and
displays the caption “Read Loop On” as long as the timer
loop is activated. However, as there are several other
functions, including the alarm functions which use timers, it
is not recommended to leave the read temperature loop on
while performing other functions because of the reduced
response time of the program.
Figure 20.0 Access Clock Commands
CLOCK REGISTER COMMAND SET
The user may gain access to the Clock Command Set by
clicking “Access Clock” on the tree-view. When clicked,
the program will immediately read all seven internal device
clock registers. The user may read the system time by
clicking “Access Clock(current)”. This command collects
the user’s PC time and segments the data into a format
usable by the DS1629. The user can then simply click the
“Write Clock” button to write the current system time
directly into all seven device registers. See Figure 20.0
Access Clock Commands.
Please note that the clock registers are partitioned
according to the data sheet section “Operation-Real Time
Clock/Calendar”, with clock register “00” containing
seconds data and clock register “06” containing the year. It
is also important to note that register “03” contains the day
information and that Sunday is defined as day one.
READ TEMPERATURE COMMANDS
There are several ways to read the device temperature. As
stated previously, the user may click the “Read Temp”
button on the “Operation” tab to activate a timer loop which
continuously reads register “AAh” to acquire the current
temperature.
CLOCK/TEMPERATURE ALARM SOUNDS
Audible alarm sounds are provided for user convenience.
The user may click the “Settings” menu for access to the
alarm sounds form (see Figure 21.0). The program selects
the bell as the default alarm sound. However, the user may
choose the voice sounds if he so chooses. The user may
also select the “Test” button to make certain that the *.wav
files are present and in the correct folder for program
access. The *.wav files must be in the same directory as
the program executeable to work properly. Once the alarm
sounds form is active, the user may click F5 on the
keyboard to test all available sounds.
The user may also click “Read Temperature” on the treeview to perform a single read of the temperature register
without setting a loop timer. A single temperature read can
also be performed by clicking the “Read Temp” button on
the “Command Set” tab.
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Figure 21.0 Access Alarms Sounds
Figure 22.0 Oscillator Output Control
OSCILLATOR OUTPUT FREQUENCY CONTROL
Figure 23.0 Saving 1629 SRAM
The Oscillator Output control form (see Figure 22.0)
resides under the “Settings” menu. Upon program startup, the oscillator output is set to OSC f0, where the MSB of
the configuration register are set as OSC1=OSC0=1.
However, during program initialization these bits are first
set to zero to disable the oscillator output before setting the
default state of these bits to one.
The user may click “Set OSC On” on the “Operation” tab to
activate the oscillator output frequency. However, since the
default state is on, the program will first disable the output
to allow the user to choose the desired frequency from the
“Settings” menu oscillator output form. If the user does not
select a frequency of OSC 1/8f0 or OSC 1/4f0 or OSC f0,
the default setting of OSC f0 will be activated. By clicking
the “Enable Oscillator” button on the “Register Set 2” tab,
the program will automatically set OSC f0.
SAVING DEVICE SRAM DATA
The 1629 device has 32 bytes of SRAM storage, which is
saved to the text file “1629SRAM.txt” when the user clicks
the “Save SRAM Data” command button on the Save
DS1629 SRAM Data form (see Figure 23.0). This form is
located under the “File” menu.
When clicked, the program first reads the SRAM contents
before writing the data to a text file. The “1629SRAM.txt”
file typically resides in the program executeable directory.
As text data, the file can be read by any text editor
program.
REGISTER SET 1 TAB-CLOCK REGISTER
By clicking on the “Register Set 1” tab (see Figure 24.0),
the user interface will become active. The “Register Set 1”
tab allows the user to both read and write to the DS1629
real time clock.
At program start-up the real time clock registers are read to
determine the clock settings. The user may click “Read
Loop Off” to start a read loop time, which will perform
continuous reads of the device clock registers. By clicking
“Read Clock Register”, a single read of all seven clock
registers is performed.
Once the user has entered the desired data into each of
the seven time keeping registers, he may click the “Write
Clock Register” command button to write the data directly
into all seven registers simultaneously. The user should
also be reminded that the current time is written into the
device if “Write Time/Date” is clicked on the “Operation”
tab.
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directly below the “Read Alarm” command button.
Figure 24.0 Register Set 1 Tab
Write Alarm- When the user has entered the desired alarm
data into each of the four clock alarm registers located
directly below the command button, the “Write Alarm”
button may be clicked to write the alarm setting into the
device. The settings are automatically read back under the
“Read Alarm” column.
Figure 25.0 Register Set 2 Tab
REGISTER SET 2 TAB FUNCTIONS
The “Register Set 2” tab (see Figure 25.0) allows the user
access to the Configuration Register functions as well as
the Slope and Counter registers. This screen also allows
for automatic enabling and disabling of the oscillator
output, as well as providing access to the Clock Alarm and
SRAM registers.
Read Config.- By clicking the button a timer is activated
which immediately sets the command button caption to
“Read Loop On” and performs a continuous read of the
MSB and LSB of Configuration Register.
Write Config.- Each click this button will cause a one-time
write to the MSB of the Configuration Register. Write
commands to the LSB portion of the Configuration Register
are not allowed because the LSB provides only status
information and writing data to the LSB can and will cause
problems in device command interpretation.
Read Slope- The Slope register returns
COUNT_PER_C value when this button is clicked.
the
Read Counter- The Counter register returns the
COUNT_REMAIN value when this button is clicked.
Enable Oscillator- The OSC1 and OSC0 bits in the
Configuration Register are both set high when this button
is clicked.
Disable Oscillator- The OSC1 and OSC0 bits in the
Configuration Register are both set low when this button is
clicked.
Read Alarm- By clicking this button, all four DS1629 clock
alarms registers are read into the text boxes located
Read SRAM- Upon program start-up, the SRAM address
pointer is set to location “00”. The user may enter into the
address text box “00” to “1F”. Since there are only 32 bytes
of SRAM space, if the user reads from an address higher
than “1F” the SRAM address pointer will automatically
wrap around back into the 32 byte address space
available.
Write SRAM- The user may enter any hex address in the
specified 32 byte range along with any byte wide hex data
in the appropriate text box. When the user clicks the “Write
SRAM” button, the data is written to the specified address.
THE APPLICATION TAB GRAPHIC
Figure 26.0 provides a block diagram that illustrates the
internal functions of the DS1629. There are eleven major
functional areas in addition to the crystal and oscillator
divider circuits. In a typical application, the 2-wire circuitry
will interface to a CPU. The “Address and I/O Control”
block provides read/write access to the internal registers.
The “Temperature Sensor” interfaces to the “Thermal
Register” and the “Thermal Alarm” register. The thermal
registers interface to the “Thermal Alarm Comparator” and
the “Alarm Select” circuitry.
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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.
Figure 26.0 Application Tab
Figure 27.0 DS75K Start-up Splash Screen
THE TEMPERATURE SENSOR TAB
Upon successful loading of the software, the Temp. Sensor
screen as shown in Figure 28.0 should appear.
Figure 28.0 The Temperature Sensor Tab
The “Clock Alarm Register” interfaces with the “Clock
Register” circuitry which in turn interfaces with the “Clock
Alarm Comparator” circuitry. The “Alarm Select” circuitry
will determine whether a temperature or clock alarm mode
has been selected. This selection will be set by the user
through the “Configuration “Register.”
The user may set the alarm mode and the oscillator
frequency through the “Configuration “Register”, which also
provides alarm status. The DS1629 also provides both
alarm and variable frequency oscillator outputs.
The 32-bytes of user SRAM is also illustrated in the
previous block diagram. As shown, the SRAM is accessed
independently of the other device registers and is not
connected with the alarms or clock and temperature
registers.
USING THE DS75K 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 DS75K.exe executable to
view the screen shown in Figure 27.0.
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
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 DS75 device in the OTS socket provided. The DS1775
is the functional equivalent of the DS75 but has a fixed
address of location “000”. The DS1775 is not included in
this kit because of its package type. The package type of
the DS1775 is an SOT23-5 (5-pin package) while the DS75
is an 8-pin SO (150mil) and will fit into the OTS socket
provided on the 87-1702K-000 2-Wire Board.
Click the “On” button to begin immediately reading the
device temperature in both Celsius and Fahrenheit.
Click on the “->DS75/DS1775” tree-view to obtain access
to all of the DS75 internal registers.
The DS75 internal registers are organized as device
pointers. Table 7.0 illustrates the settings for the four
internal pointer registers of the DS75. Please note that the
DS75 and the DS1775 are functionally equivalent. The
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only functional difference is that the DS1775 operates at a
fixed address of “A2=0, A1=0, A0=0” while the DS75 may
reside from address “000” to address “111”.
Table 7.0 Pointer Registers
F1 and F0 are O.S. Fault Tolerance bits. The fault
tolerance defines the number of consecutive conversions
returning a temperature beyond limits required to set the
O.S. output in an active state. The DS75 will power-up at
“00”, such that a single occurrence will trigger a fault. For
higher fault tolerances, F0 and F1 can be changed a
shown in Table 9.0.
Table 9.0 Fault Tolerance
The software is designed to initialize the DS75 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 JP5, JP6 and JP7 should be in place. When the
DS75 150mil SO is used, place the device in the OTS.
JP9, JP10 and JP13 will be added for addresses other
than “000”.
TEMPERATURE SENSOR ALARMS
The temperature high and temperature low flags are set
and monitored in the internal device registers. By writing
to 03h and 02h the user may set the Temp. High (Tos) and
Temp. Low (Thyst) registers, respectively.
When the high temperature exceeds Tos the output O.S.
will be active. The polarity of the O.S. output is determined
by setting the “POL” bit. If POL = “1”, the active state of the
O.S. output will be high and the normal, or standby state
will be low. A “0” stored in this location sets the thermostat
output to an active low state with a high O.S. output
inactive state.
For user convenience, the blue Tos LED on the “Chart
Temperature” tab turns red when the Tos high limit has
been exceeded. It will turn blue again when the device
temperature falls below the Thyst setting.
CONFIGURATION REGISTER
R1 and R0 are the Thermometer Resolution bits. Table
10.0 defines the resolution of the digital thermometer,
based on the settings of these two bits. There is a direct
trade-off between resolution and conversion time. The
device default state is “00” (9-bit conversions).
Table 10.0 Thermometer Resolution
TEMPERATURE CHARTING
By clicking the “Chart” icon button, the software will begin
plotting the device temperature (see Figure 29.0). 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. The user may
also click “Halt” to halt the temperature plot and click
“Chart” to restart the plot.
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.
The DS75 Configuration Register is shown in Table 8.0
Table 8.0 DS75 Configuration Register
If SD is set to “1”, the DS75 will go into a shut down mode
and will revert to a low-power standby mode. The powerup default state is “0” (continuous conversion mode).
The “Chart Temp.” icon button can be used to clear an
existing temperature chart and to plot new temperature
data.
If TM is set to “1” the device will revert from its normal
comparator mode to an interrupt mode. The power-up
default state is “0” (comparator mode).
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Figure 29.0 DS75K Temperature Charting
Figure 30.0 Register Access Tab
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.
Set 9 to 12-Bit Resolution: This set of commands is
controlled by writing to the R1,R0 bits in the Configuration
Register.
THE REGISTER ACCESS TAB
To view the Register Tab, as shown in Figure 30.0, simply
click on the word “Registers” at the top of the tab form. The
Register Tab provides user access to the device internal
registers.
The following list of commands is available via the Register
tab:
Read Temp. Loop On/Off (Pointer Register 00): When
clicked, the command performs a continuous read of the
temperature register, as shown in Figure 30.0.
Configuration Reg. (Pointer Register 01): The user may
read the Configuration Register to set the polarity of O.S.
output as well as to set the output interrupt mode or to put
the device in standby mode. The user may also set the
fault tolerance and the thermometer resolution. See the
“Operation-Programming” section for the DS75 data sheet.
Write Tos (Pointer Register 03): This command writes the
contents of the edit boxes to the Temp. High register. The
value written will set the temperature high threshold for
operation of the Tos (O.S) output.
Read Tos (Register Pointer 03): This command allows the
user to read the contents of the Temp. High register. See
“Thermostat Setpoints Programming” in the data sheet.
Write Thyst (Register Pointer 02): This command writes
the contents of the edit boxes to the Temp. Low register.
The value written will set the temperature Low threshold for
operation of shutting off the Tos O.S. output, provided the
output is already active.
Set/Clear Polarity Bit: This command is controlled by
writing to the Configuration Register. If POL is “1”, the
active state of the Tos output of the DS75 will be high. A
“0” stored in this location sets the thermostat output to an
active low state. The power-up default state is “0” ( active
low output).
Set Fault Tolerance[F1,F0]: This command is controlled by
writing to the Configuration Register. By clicking on the
ListView on the “Register” tab the user may change the
previous conversion setting. For example, by clicking on
the “Fault Tolerance[F1,F0][1,1] the user will send “7Ch” to
the Configuration Register. This command provides 12-bit
Resolution and sets the polarity bit to an active high state
along with a Fault Tolerance level of “6”.
Set Thermostat Mode TM: This command is also controlled
by writing to the Configuration Register. By clicking on the
ListView on the “Register” tab the user may set the “TM” bit
to “1”. Thus, changing the device output from comparator
mode “0” to interrupt output mode. See “O.S. Output
Transfer Function Figure 2”, in the DS75 data sheet.
Shut Down Mode SD: Clicking this command in the
ListView of the “Register” tab will set the “SD” bit in the
Configuration Register to “1” and put the device in standby
mode. The device will stop continuous conversions and the
O.S. output will be remain unchanged in comparator mode.
The user should expect to see “65” sent to the device
Configuration Register. Thus, with this software command,
the polarity bit is set to “1” along with a 12-bit temperature
resolution.
Read Thyst (Register Pointer 02): This command allows
the user to read the contents of the Temp. Low register.
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