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TDC1000: TDC1000 application question support!

Sulyn ZHANG
Expert 8700 points
Part Number: TDC1000
Other Parts Discussed in Thread: TDC7200

Hi Team,

We have penetrated our TDC1000+TDC7200 solution to my customer for detect of liquid level and concentration application. Now customer's board come back and is debugging on this, they met some question or issues that need expert to help support, thanks a lot!

Question 1. For TDC1000, how or when to select Short TOF and standard TOF? Do we have suggestions or guidelines for this;

Issue 1: If TDC use Standard TOF, TDC7200 use Mode 2, Ultrasonic driver frequency is 1MHz, TDC1000's TRIGG use rising edge, TDC7200's start and stop also use rising edge. Then if we use oscilloscope to monitor, the start and stop waveform is normal, but TDC7200's INTB didn't show sometimes. Do you have some idea why this happen?

Issue 2: If we still use 1MHz Ultrasonic driver frequency and TDC1000's TRIGG use rising edge, but TDC7200's start and stop use falling edge, then TDC7200's INTB will show normally. BTW, if we use 500kHz Ultrasonic driver frequency, TDC1000's TRIGG use rising edge, TDC7200's start and stop use rising edge, then the TDC7200's INTB will show normally, can you also help clarify why it is?

Issue 3: Now customer is using 1MHz Ultrasonic driver frequency, TDC1000 use rising edge, TDC7200's start and stop use falling edge, customer use 8MHz crystal(10ppm), the test result showed that these is about several nanosecond fluctuations or even tens of nanoseconds fluctuations sometimes, so do we have some solution or suggestions to improve this?

Thanks a lot for your great support on this!

Best regards,

Sulyn

  • 0
    TI__Mastermind 23810 points
    We are out of the office due to the Thanksgiving holiday, but our TDC expert will get back to you next week.
  • 0 in reply to Clancy Soehren
    TI__Expert 8700 points

    Hi Clancy,

    Thanks for the note, happy thanksgiving day!

    Will wait for expert's feedback after they are back, thanks!

    Best regards,

    Sulyn

  • 0 in reply to Sulyn ZHANG
    TI__Expert 8700 points

    Hi Team,

    Would some expert help me check my above questions? My customer is waiting for debug, thanks a lot for your support!

    Best regards,

    Sulyn

  • 0 in reply to Sulyn ZHANG
    TI__Expert 8700 points
    Hi Team/Expert,
    I still haven't got the feedback from your side, my customer now urgently need the support, would you pls help look into these issues? Thanks a lot for the support!

    Best regards,
    Sulyn
  • 0
    TI__Genius 11015 points
    Sulyn,

    We typically use the Short TOF to measure distances of a very few cms (typ < 10cms) for all purpose we use the Standard TOF. Also the short TOF measurement is selected if the value of the TIMING_REG[9:0] field is less than 30.

    Issue 1: The INTB will show up after the last STOP is received, please check if you have received all the STOP signals have been received. If the INTB does not show up it means the device is still expecting a STOP signal. INTB is typically used in Multi Cycling averaging mode.

    Issue 2: Your readings are perhaps received all the STOP signals that is expected to received and hence triggers the INTB pin.

    Issue 3: We recommend that the customer use 1MHz transducer for measurements through liquids. However if the customer insists on 8Mhz transducer please do a multi cycling averaging to check if the readings are stable.
  • 0 in reply to Bharat Aravamudhan
    TI__Expert 8700 points

    Hi Bharat,

    Thanks a lot for your support and this is helps! I feedback to customer and we did more test, below are more feedback and further support may need you help:

    Currently, the Ultrasonic driver frequency is 1MHz, TDC1000 was configured “Standard TOF” and “Single echo receive Mode”, also was set to transmit one pulse and then receive one return signal; For TDC7200, was configured Mode 2 and receive one stop signal. TDC1000’s TRIGG are using rising edge, TDC7200’s start and stop are also using rising edge. With above configuration, when we use the oscilloscope to monitor, we can see the start and stop signal are generated normally but we still can’t get the INTB every time. Yes customer is using the INTB signal to know if the measurement is stopped or not.

    So the further question here is that if TDC1000 are using “Single Echo receive mode”, then we will not get the INTB signal every time?

    Maybe you are mis-understanding, now customer are using 1MHz as Ultrasonic driver frequency, the 8MHz mentioned last time is the crystal osc frequency but not Ultrasonic driver frequency.

     

    We also did more test at customer side, the Ultrasonic driver frequency is still 1MHz, TDC1000 was configured “Short TOF” and “Single Echo receive mode”, also was set transmitting one pulse and receive one return signal; TDC7200 was configured Mode 2 and was set to receive one stop signal. TDC1000’s TRIGG are using rising edge, TDC7200’s Start and Stop are also using rising edge, in these above configuration or setting, TDC7200’s INTB will generate every time and the test accuracy is very high.

     

    But in customer’s project, they want use the “Stand TOF” but not “Short TOF” of TDC1000, but as described above, seems the INTB won’t always generated and accuracy is not good. Can you help give some idea about this issue? Thanks.

     

    BTW, for the reference clock that used for TDC1000 and TDC7200(The 8MHz crystal Osc as mentioned above), if customer want to realize 1ns accuracy, when they choose the crystal Osc, what’s the max ppm can be accepted?

    Best regards,

    Sulyn

  • 0 in reply to Sulyn ZHANG
    TI__Expert 8700 points

    Hi Bharat or other experts,

    Would you pls help further look at this issue, my customer is now urgently debug and hope to move ahead with our support, thanks!

    Best regards,

    Sulyn

  • 0 in reply to Sulyn ZHANG
    TI__Genius 11015 points
    Sulyn,

    Please let me know the target that you are trying to measure in your setup.
  • 0 in reply to Bharat Aravamudhan
    TI__Expert 8700 points

    Hi Bharat,

    Thanks for the support! The product is to detect Liquid Level Concentration by Ultrasound.

    Would you pls kindly check above questions, thanks a lot!

    Best regards,

    Sulyn

  • 0 in reply to Sulyn ZHANG
    TI__Genius 11015 points
    Sulyn,

    Please note I could not replicate your standard TOF in my lab here. Please send me the setup file & or register map settings for the same for me to check at our lab.
  • 0 in reply to Bharat Aravamudhan
    TI__Genius 11015 points
    Sulyn,

    Please send me the setup file to my email. We can take this issue outside the e2e forum.
  • 0 in reply to Bharat Aravamudhan
    TI__Expert 8700 points

    Hi Bharat,

    Many thanks for your support! Now customer already solved most issues based on your suggestion. They may have new issue, I already let customer know this link and if they have issue, they will ask you later.

    Best regards,

    Sulyn

  • 0 in reply to Sulyn ZHANG
    TI__Intellectual 1020 points
    Hello Sulyn,

    If possible, can you please share the customer settings with Bharat directly and follow up on private email. I will close this ticket for now.

    Regards,

    Vaibhav