DS1703K

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Figure 14. DS1722 Thermometer Tab

The first item of importance on this form is the SPI or 3-wire Interface option button. When using

the DS1722, this should be the first option selected to ensure the part communicates properly.

Although these buttons do not change anything internal to the part, the software transmits and

receives data much differently based on the option chosen. If the SPI interface is chosen please note

that the communication process is quite slow. The DS9123 serial interface module is not designed

for SPI data transfer, and thus the process is tedious. All commands are functional, but the software

may be slow to respond to button presses and changes.

The two large buttons toward the top left of the form are used to start and stop temperature

conversions. The functionality of these buttons is directly tied to the status of the option buttons

located in the Device Preferences section. If the 1-Shot mode is selected, clicking Start Temperature

Conversion reads the configuration register from address 00h, sets the 1SHOT bit (bit 4), then writes

the data to address 80h. If the DS1722 is in Continuous conversion mode, pressing the button does

nothing. Pressing the Stop Temperature Conversion button will put the device in 1-Shot mode. The

configuration register is read from address 00h, the SD bit (bit 0) is set, and then the data is written

to address 80h.

The bottom section of the form allows the user to select the resolution the device is to use to report

temperature. Pressing any of these buttons changes the contents of the configuration register to the

desired resolution state. This is done by reading address 00h, modifying the R0-R2 bits, and then

writing the data to address 80h.

DS1722 Registers Tab

The second tab for the DS1722 is the Registers tab. This tab displays the status of the configuration

register. When this tab is selected the configuration register is not read every 2.5s as indicated in the

previous section. However, the temperature register is still read. The three combo boxes on the right

side of the form allow the user to view the current settings of the register, and change them to a

different setting. The hex value of the configuration register is shown in the small text box at the top.

This text box is read only.