Getting Started with the DS1840K . . .
6 of 13
Evaluating the DS1846
Note: Before experimenting with the DS1846, it may be necessary to acquire device samples and a socket.
Some kits may not have been shipped with these components due to availability at the time of packaging.
The required socket is a Wells 676-320 (see figure 8). Please contact the factory for more information.
Contact information can be found at the end of this document.
The DS1846 also uses the Dallas 2-Wire serial interface. Since it is a multi-drop interface, an address pin
on each device gives the ability to assign each device on the bus a unique address. However, the DS1846,
unlike the other featured pots, only provides one address pin, A0. To provide the most flexibility, the
DS1840K Demo Board allows you to set A0 using DIP
switch 7 (see Figure 3 above). Likewise, a DIP switch is
also provided for WP (DIP switch 8). A DIP switch in the
“ON” position grounds the signal. A DIP switch in the
“OFF” position, allows a pull-up resistor to pull the signal
to Vcc. The address signal (A0) has an external pull-up
resistor, while the Write Protect (WP) signal has an
internal pull-up resistor. If the device is “write protected,”
then the wiper can not be moved and the memory can not
be modified. The default DIP switch settings for the
DS1846 are both “ON” (switch 7 and 8). This corresponds
to a device address of 0h and NO write protection.
Figure 8. DS1846 Socket.
The DS1846 contains three non-volatile potentiometers, memory, and a MicroMonitor. The physical
device pins associated with each pot are Lx, Wx, and Hx, where x is either 0, 1 , or 2. Each of the pot
terminals can be accessed directly at the
“test points” near the front of the board
(see Figure 9). Using a multi-meter, the
resistance can be measured from these
test points (make sure no jumpers are
installed on J7, J8, or J9). Measuring
from Hx to Lx you will see the end-to-
end resistance of that particular pot.
Likewise, measuring from Wx to Lx will
result in a resistance depending on where
the wiper was last set.
Figure 9. DS1846 jumpers and test points.
In addition to features similar to the other digital potentiometers, the DS1846 also provides a
MicroMonitor. J6 provides easy access to the MicroMonitor signals. Likewise, test points are also
provided for these extra signals. For more information regarding the MicroMonitor, please refer to the
DS1846 datasheet.
