ad5171 Analog Devices, Inc., ad5171 Datasheet - Page 16

• Manufacturer Part Number: ad5171
• Description: 64-position Otp Digital Potentiometer
• Manufacturer: Analog Devices, Inc.

AD5171
CONTROLLING THE AD5171
There are two ways of controlling the AD5171. Users can either
program the devices with computer software or employ external
I
SOFTWARE PROGRAMMING
Due to the advantage of the one-time programmable feature,
users may consider programming the device in the factory
before shipping it to end users. ADI offers device programming
software that can be implemented in the factory on PCs run-
ning Windows 95 to Windows XP platforms. As a result, external
controllers are not required, which significantly reduces develop-
ment time.
The program is an executable file that does not require the user
to know any programming languages or programming skills. It
is easy to set up and use. Figure 33 shows the software interface.
The software can be downloaded from www.analog.com.
Write
The AD5171 starts at midscale after power-up prior to the OTP
programming. To increment or decrement the resistance, move
the scrollbar on the left. To write any specific values, use the bit
pattern control in the upper screen and click Run. The format
of writing data to the device is shown in Table 7. Once the
desired setting is found, click Program Permanent to blow the
internal fuse links for permanent setting. The user can also set
the programming bit pattern in the upper screen and click Run
to achieve the same result.
2
C controllers.
Figure 33. Software Interface
Rev. B | Page 16 of 24
Read
To read the validation bits and data from the device, click Read.
The user may also set the bit pattern in the upper screen and
click Run. The format of reading data out from the device is
shown in Table 8.
To apply the device programming software in the factory, users
need to modify a parallel port cable and configure Pin 2, Pin 3,
Pin 15, and Pin 25 for SDA_write, SCL, SDA_read, and DGND,
respectively, for the control signals (Figure 34). Also lay out the
PCB of the AD5171 with SCL and SDA pads, as shown in
Figure 35, such that pogo pins can be inserted for the factory
programming.
Figure 35. Recommended AD5171 PCB Layout. The SCL and SDA pads allow
pogo pins to be inserted so that signals can be communicated through the
Figure 34. Parallel Port Connection. Pin 2 = SDA_write, Pin 3 = SCL,
parallel port for programming (Figure 34).
Pin 15 = SDA_read, and Pin 25 = DGND.
GND
SCL
V
DD
W
13
25
12
24
11
23
10
22
9
21
8
20
7
19
6
18
5
17
4
16
3
15
2
14
1
100Ω
100Ω
100Ω
R3
R2
R1
A
B
AD0
SDA
WRITE
READ
SCL
SDA