Reg: Problem in Writing RDAC of AD5274 through I2C

Gopi Chand on Aug 23, 2019

Hello All,

I tried to change the RDAC Register value of AD5274BRMZ-20 (20K-Max) through I2C. But the resistance between the A & W pins is always constant to 9.25K(Mid Value).

I have sent the following Values through I2C.

Device Address : 0X2C (I have tried 2F also)

Command bits : 0001 (C3,C2,C1,C0)

Data: 0X3C

Attached the Image of the Waveforms. Could anyone let me know, where it went wrong.

Waveforms

0 koushik.kops

on Aug 26, 2019 6:51 AM over 2 years ago
Hi Gopi,

Could you share the schematic of your design?

Regards,

Koushik
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0 Gopi Chand on Sep 2, 2019 9:39 AM over 2 years ago in reply to koushik.kops

Hello Koushik,

Here are the schematics. The I2c line pulled to high with 2.2K.
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0 koushik.kops

on Sep 12, 2019 5:38 AM over 2 years ago in reply to Gopi Chand
Hi,

By default the update to wiper position is disabled. you need to send the following code to enable it:

Address: 0x2C

Command:0x08

Data:0x02

Please refer to command 7 in table 12. Table 14 and 15 will give you detailed explanation. You need to enable C1 bit in the Control register to enable update of wiper position.

Regards,

Koushik
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