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ADS8686SEVM-PDK: ADS8686SEVM-PDK

Part Number: ADS8686SEVM-PDK
Other Parts Discussed in Thread: ADS8686S

Hello,

I tried to capture signal and see on GUI, I used one of the analog channels and send 20 mVpp - 200 mHz sine signal, but i have just read 0V on analog channel AIN0 on GUI, after i connect device with software. All jumpers are set as default positions. How can i fix this problem?

Thank you. 

  • Hi Gozde,

    Welcome to TI E2E forum.

    Was D3 light on the EVM on? If not, did you provide an external +5.5V power supply to pin 3 of terminal block T1? Which position did you install your jumper on JP7? 

    Also, did you see the green color "HW CONNECTED" on the bottom of the GUI software? This can tell you if the GUI and PHI controller card was successfully connected to the EVM.

    You can change the setting of "Y Scale fit" from default "Auto mode" to "Fit code range" on the top of GUI software in case the captured signal/code is too small for you to see?

    Regards,

    Dale

  • Hi,

    Was D3 light on the EVM on?  - Yes

    Which position did you install your jumper on JP7?  - Closed between pins 2 and 3

    Did you see the green color "HW CONNECTED" on the bottom of the GUI software?  - Yes

    You can change the setting of "Y Scale fit" from default "Auto mode" to "Fit code range" on the top of GUI software in case the captured signal/code is too small for you to see? - I tried this but there was no difference on results. 

    JP1,JP3,JP5 are open, JP2 and JP4 :open, JP6 closed, JP7: closed between pins 2  and 3 , software is connected and LED D5 on, LEDs D1 and D2 on the PHI blinking

    I cannot capture the signal on GUI. Is there any other option to solve this problem?

    Thanks for your help.

    Kind Regards. 

  • Hi Gozde,

    When you said "cannot capture the signal on GUI", do you mean you could not capture and see any signal in the GUI including DC or short input? Is you EVM-PDK brand new?

    Can you take a screenshot for Device Configuration page and also Time Domain Display page in the GUI? these JPx can be left open if a software mode is configured and selected in the GUI.

    Regards,

    Dale

  • Hello,

    Do you mean you could not capture and see any signal in the GUI including DC or short input? - I captured 0 V DC.

    Is you EVM-PDK brand new? - Yes

    You can see the screenshots below. I sent 1 V, 200mHz sine to AIN0, but i captured 0 V DC even I used fit to code range button on GUI. (Device mode:software)

    Should i left all the JPs open ? 

    Kind Regards.

  • Hi Gozde,

    Your configuration page is the default configuration (parallel interface and software mode etc.) after the GUI is launched.

    Let's do the following test first to make sure your EVM-PDK works:

    1. You can keep the jumpers on the EVM like what I did in the following image (these jumpers will not actually take control because the ADC will work in software after the GUI is launched, these pins will be controller by the PHI card and the GUI software). An external +5.5V power supply is connected to TP3 (5V5).

    2. Do not connect any signal, capture data in the time domain without any change in the GUI. You should be able to see waveforms and data of AIN0A and AIN0B similar to those shown in the following image:

    Time domain:

    Histogram:

    Please let me know your test result.

    For "200mHz" you mentioned, is the frequency of your signal 200 millihertz (0.2 Hz)? You can check 1kHz sinewave signal first after you do the test according to my suggestion.

    Regards,

    Dale

  • Hello,

    What is the J7's position? I tried this test setup you mentined, and again i cannot capture the test signal. The results are the same (0 V DC). J7 was open completely. 

    Kind Regards.

  • Hi Gozde,

    Are you asking JP7? there is no J7. The jumper on JP7 should be placed between pins 2 and 3 to select external power supply, see the schematic on page 32 of ADS8686SEVM user guide.

    I'm curious how D3 on your EVM is on if JP7 was completely open.

    Regards,

    Dale

  • Hello,

    Yes, the jumber I mentioned about was JP7. I tried it both on and off and could not read the test signal via GUI. In both cases the D3 led was on. I am sending you the image. Could it be a hardware problem or an issue with the software version?

    Best Regards.

  • Hi Gozde,

    I would suggest you to uninstall the GUI, download the GUI from the link and re-install the EVM GUI software. If it still does not work with default configurations in the GUI and floating input on the EVM, that should be hardware issue and the ADC could be damaged.

    Regards,

    Dale

  • Hello,

    I reinstalled the GUI and tried to capture the 5.5 V test signal. Firstly, i could not see the signal on GUI, then i used the RST button on the board and results can be seen below. However, i could not capture the analog signal on AIN0 again. 

    Regards.

  • Hi Gozde,

    This ADC definitely requires a /RESET low pulse to reset the device after it's powered up, but the GUI software should send it to the ADC, there is no need to press the RESET button(S1) before capturing data on the EVM, can you monitor the /RESET signal on pin 36 of the ADC or pin 1 of S1 to see if any low pulse is sent by the PHI controller card after the ADC is powered up?

     For AIN0 "i could not capture the analog signal on AIN0 again", your EVM GUI already captured the data and the data for both AIN0A and AIN0B has been shown in your time domain and histogram, the data for AIN0A channel is a DC signal between 2.091~2.093V (code: 6851~6858), this is a voltage when your ADC's input is floating, see the highlight in red in the following image. You did not connect any external signal. 

    Regards,

    Dale

  • Hello,

    Yes, it is true. I can see the 2.091~2.093V DC signal on GUI when  ADC's input is floating. But, my main problem is that i cannot capture any AC signal when i connect the external source and send the 1 kHz, 1V  sine to AIN0. 

    Regards.

  • Hi Gozde,

    As long as the ADC can successfully capture a DC signal or floating input, definitely it should work for AC input signal as well because the ADC and the GUI software can not detect whether the input signal is AC or not, they just capture and convert the signal which is applied on ADC's input.

    In your last post, your mentioned "I reinstalled the GUI and tried to capture the 5.5 V test signal.", but the data in the GUI from your screenshots clearly showed that the ADC's input was floating because 2.091~2.093V DC signa is an internal bias signal of ADS8686S ADC. When an external signal is properly connected to the ADC's input, you should not be able to see this bias voltage, so I'm pretty sure either your connection from your signal source to the EVM is not good or the connection between the connector and ADC's input is broken. 

    I would strongly suggest you to double check your connection with a multimeter or check signal with an oscilloscope!

    Regards,

    Dale

  • Hello,

    I checked with an oscilloscope that the signal is coming to the analog input (AIN0) correctly, I also looked at the 28th pin of the ADC with an oscilloscope and saw that the signal is also coming there. When I check the connection through the software and the LEDs on the board, I do not see any problem also. 

    Regards. 

  • Hello,

    When I apply 5.5V from the TP3 pin, I did not apply any signal to the input of the ADC, I left it floating. After capturing the DC signal. I removed the external 5.5V and applied a 1V -1kHz sine signal to the analog input (AIN0). I'm sending the screenshots. When I checked the signal from both the connector and the ADC pin (pin 28) with the oscilloscope, I found that it was correct, but I could not observe the digital output on the GUI.

    The signal I sent:

    the connector I control with an oscilloscope:

    the signal I read from the connector and the ADC pin. (this signal comes to the connector and ADC pin the same as the signal I sent)

    I think the problem may be caused by a software problem.

     

    Kind Regards.

  • Hi Dale

    I have proposed customer to connect analog supply AVDD on the terminal block T1 and it seems that problem has been solved. 

    ItS stated in the below user guide.

    ADS8686SEVM-PDK User's Guide (ti.com) (page16)

  • HI ,

    I apologized for the late response because I was taking time off in the past two days.

    Based on your description below, you should not remove the external 5.5V power supply when you apply AC signal to the EVM. I already recommended you to check 5.5V external power supply. The EVM always requires an external  5.5V power supply on either TP3 or T1 terminal block.

    "When I apply 5.5V from the TP3 pin, I did not apply any signal to the input of the ADC, I left it floating. After capturing the DC signal. I removed the external 5.5V and applied a 1V -1kHz sine signal to the analog input (AIN0)"

    Hi Mustafa,

    Thank you for your update.

    Regards,

    Dale