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ADC TLV2556 NOT SENDING A VALID DATA

Other Parts Discussed in Thread: TLV2556

Hi all ,

I am working with TLV2556 based EVM. I have been trying very hard to get data from this ADC. The everything looks right (clock , configuration data, CS, eoc) but data out signal is not valid. Some value at reset remain consistent and do not vary according to analog input. 

Here I m attaching the DSO image with following legend

1st wave: CS;

2nd wave: DATA IN

3rd wave: CLOCK

4th wave: DATA OUT

  • Ashutosh,

    Welcome to the forum!!

    Could you please provide some more details regarding your setup.

    - What host is driving the interface signals in your screenshot?

    - In which device mode are you operating?

    - Which channels have an input signal connected and what is the output you are expecting?

    - What is the system you are trying to design using this ADC?

    Thanks.

    Regards,

    Sandeep

  • Thanks For reply Sandeep;
    The host interface is FPGA board, zedboard. A VHDL code is used for SPI interface. I have tried all MODE, basically with SPI-00 Mode.
    An analog signal generated by function generator (unipolar 100 Hz SINE 1 V ) is connected to channel 0 of ADC and all other channel are grounded . I was expecting that, after sending the command for channel 0 , in next cycle there must be some sequential data.

    -- Regards Ashutosh.
  • Ashutosh,

    Sorry about this delay in responding.

    Since you are using the zedboard as your host it raises the question - how are you powering up the EVM? If you are still using the 5-6K Interface board to drive the power supplies, please ensure that there are no conflicts between the power supplies and interface signals between the two hosts.

    Have you made any other changes to the default configuration of the EVM?

    Thanks.

    Regards,

    Sandeep

  • Hi, sandeep
    I am using Configuration as:
    Reference Voltage : External, using w3 and w4 jumper, and at ref: 3.3 V driven from Vcc.
    Vcc/ Gnd is connected with Vcc/Gnd of Zedboar PMOD connector, with 3.3 Vdc,
    No, Amplifier has been used. No other power supply used.