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ADS8201 iRGE. Most significant bit erroneus

Other Parts Discussed in Thread: ADS8201

When the input voltage is crossing the 2,5V with a sine wave signal, see the picture below. If the sine wave is all the time below or above the 2,5V, there is no spikes visible. Is the problem in the communication?

5V, 5V with a sine wave signal, ADS8201 iRGE. Most significant bit erroneus, see the picture below. If the sine wave is all the time below or above the 2, there is no spikes visible. Is the problem in the communication or configuration with the converter? Antti Martikainen, when the input voltage is crossing the 2

  • Hi Antti,

    Welcome to the e2e forum!  Can you post a similar screen shot with a full scale input?  What processor are you using to communicate with the ADS8201?

  • Hi,

    Here is the picture with a higher voltage. We are using Renesas H8SX1657 microcontroller in this application.

    Regards,

    Antti Martikainen

  • Hi Antti,

    This is a bit strange - not what I was expecting to see...  The picture you sent has five peaks/spikes and the interesting thing to me is that the second spike looks like it would be the correct data point if it were in the first position.  Similarly, the forth looks like it would belong in the third spot.  Can you post the actual content of that data array so we can get a better idea of the conversion results associated with the excursions?

  • Hi Tom,

     

    The Hex data is below. At the moment I do not know the reason for this phenomenon. Might be something in the communication between the controller and AD converter. All the (three) prototype boards have the same phenomenon.

    Regards,
    Antti

     

     

    EE30
    F130
    F3E0
    F5E0
    F790
    F8E0
    F9E0
    FAC0
    FB30
    FBF0
    FC40
    FCA0
    FCB0
    FC20
    FB60
    FA40
    F8C0
    F6F0
    F4A0
    F240
    EF70
    EC70
    E950
    E5C0
    E210
    DE20
    D9F0
    D5D0
    D150
    CCE0
    C830
    C370
    FEA0
    B9B0
    B500
    AFF0
    AB30
    A630
    A150
    9CA0
    97C0
    9360
    8EE0
    8A90
    8670
    8280
    BEB0
    7B30
    77D0
    74D0
    71F0
    6F60
    6D10
    6B00
    6940
    67D0
    66B0
    65D0
    6540
    6510
    6520
    6590
    6650
    6750
    68B0
    6A70
    6C60
    6EB0
    7120
    7400
    7700
    7A40
    7DD0
    41A0
    85A0
    89C0
    8E00
    9280
    96E0
    9BC0
    A080
    A540
    AA40
    AF00
    B400
    B900
    BDE0
    82B0
    C770
    CC10
    D0B0
    D510
    D970
    DDA0
    E190
    E560
    E8C0
    EC40
    EF50
    F220
    F490
    F680
    F7E0
    F930
    FA30
    FB00
    FB70
    FC20
    FC60
    FC90
    FCA0
    FC10
    FB30
    F9C0
    F840
    F650
    F3E0
    F180
    EEB0
    EB80

  • Hi Tom.

    The problem has been solved now.

    The reason to the spikes was the addressing of the configuration registers. The converter started to operate correctly, when we added chip select controls (up and down) between the configuration control addressing.

    Regards,
    Antti

  • Great news!  Thank you for letting us know!