AD5170 Analog Devices, AD5170 Datasheet - Page 16

• Manufacturer Part Number: AD5170
• Description: 256-Position Two-Time Programmable I2C Digital Potentiometer
• Manufacturer: Analog Devices

AD5170
EVALUATION SOFTWARE/HARDWARE
There are two ways of controlling the AD5170. Users can either
program the devices with computer software or external I
controllers.
SOFTWARE PROGRAMMING
Due to the advantages of the one-time programmable feature,
users may consider programming the device in the factory
before shipping the final product to end-users. ADI offers a
device programming software that can be implemented in the
factory on PCs running Windows 95 or later. As a result,
external controllers are not required, which significantly
reduces development time. The program is an executable file
that does not require any programming languages or user
programming skills. It is easy to set up and to use. Figure 41
shows the software interface. The software can be downloaded
from www.analog.com.
Figure 41. AD5170 Computer Software Interface
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The AD5170 starts at midscale after power-up prior to OTP
programming. To increment or decrement the resistance, the
user may simply move the scrollbars on the left. To write any
specific value, the user should use the bit pattern in the upper
screen and press the Run button. The format of writing data to
the device is shown in Table 7. Once the desired setting is found,
the user may press the Program Permanent button to blow the
internal fuse links.
To read the validation bits and data out from the device, the
user simply presses the Read button. The format of the read bits
is shown in Table 8.
To apply the device programming software in the factory, users
must modify a parallel port cable and configure Pins 2, 3, 15,
and 25 for SDA_write, SCL, SDA_read, and DGND, respectively,
for the control signals (Figure 42). Users should also lay out the
PCB of the AD5170 with SCL and SDA pads, as shown in
Figure 43, such that pogo pins can be inserted for factory
programming.