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Troubles with AD5142

Hi! I cann't control AD5142 with stm32f4 by SPI. I connect AD5142 like rheostat in feedback of op amp (for amplifing). Scheme in attach. But when I send some data via SPI to AD5142 it don't answer and Vout isn't change. For change resistance, I send b0001000000000001 (in 16bit mode SPI in stm32f4), then I change data to b0001000011111111 and there is no result, Vout isn't change. Oscilloscope picture correct and looks same like in datasheet. What am I doing wrong? Is it necessary to send some preparation data to AD5142, before set resistance? Could some one post tested sequential data for change resistance in AD5142?

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  • Hi,

    I believe you are building a active band pass filter. Please correct me if i am wrong.

    Here are a few things that you should check:

    1. Is AD5142 powered up throughout the process?

    2. Do you have common ground for the opamp, stm32f4 and AD5142?

    3. Could you replace AD5142 with a resistor and check if the circuit is working as it is intended to work?

    4. Could you just connect only AD5142 and stm32f4, and check if the device is responding to SPI commands?

    Regards,

    Koushik

Reply
  • Hi,

    I believe you are building a active band pass filter. Please correct me if i am wrong.

    Here are a few things that you should check:

    1. Is AD5142 powered up throughout the process?

    2. Do you have common ground for the opamp, stm32f4 and AD5142?

    3. Could you replace AD5142 with a resistor and check if the circuit is working as it is intended to work?

    4. Could you just connect only AD5142 and stm32f4, and check if the device is responding to SPI commands?

    Regards,

    Koushik

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