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TIDA-00663: TDC7200

Part Number: TIDA-00663
Other Parts Discussed in Thread: TDC7200, TPS22967, OPA857,

Can anyone explain to me how the TDC7200 communicates with the microcontroller.

My second question: what is the role of the TPS22967 .And what is the purpose of laser_on signal that it generates.

I understood the general principle of this reference design, but still confused about these two points.

Thank you in advance.

  • Hi,
    The TDC7200 communicates with the microcontroller with the SPI interface that is used for configuration and register
    access. Also the microcontroller starts the two TDC7200 with the GPIO signal BP19_PWM_GPIO_TRIGGER. Finally the TDC7200 send an interrupt signal to the microcontroller upon completion of the measurement sequence.
    TPS22967 switches on only during calibration in order to calculate the propagation delay of the entire signal chain.
    Let me know if you have additional questions.
    Thanks
    Giovanni
  • Hi 

    Thank you for your reply.It was so helpful.

    Please allow me to ask more questions, i need to understand all the details so that i can make modifications for my project.

    What i need to know is the meaning of the two signals : laser_on_threshold and VOUTN_digital. What is the purpose of  comparing the laser_on_threshold  to Laser_on , and the VOUTN_digital to the OPA857IRGTR output.

    I am also confused about the RX and TX signals of each TDC.Let me tell you what i understood and please tell me if it's correct or not. The signal TX, which is connected to TDC's STOP pin, informs about the complete emission of the light signal. And in the second TDC,the signal RX  connected to STOP pin informs about the complete reception of the same signal. The time difference between these two stops is what's nedeed for microcontroller processing.Is this correct please ?

    Thank you again

  • Hi,

    Thank you!

    Yes what you mentioned is correct.

    The first comparator U4A compare the laser_on signal, which is high when the laser is fired, against the threshold signal "laser_on_threshold" set by the TPL0202 and output TX that stops the first TDC7200(U3).
    The second comparator U4B compare the output signal of the OPA857, which has amplified the current input from the photodiode, against the threshold signal "VOUTN_digital" set by the TPL0202 and output RX that stops the second TDC7200(U6). The ToF is the difference between the ToF measured by the two TDCs.

    Let me know if you have additional questions.
    Best regards
    Gio
  • Hi 

    Thank you very much , your answers helped me a lot.

    Best regards.

  • Hi 

    Please Can you tell me what is the role of the two signals "delayed_cal" et "delayed_trigger" in SN74LVC2G14DCKR.

    Thank you for your held.

  • Hi Yasmine,

    Delayed_trigger is the delayed signal of BP_TRIG that allows the two TDC7200 to start.

    Delayed call is the inverted signal of BP_TRIG that, when is high and BP11_CAL is high, will start the calibration sequence that I was talking about in the above messages.

    Thanks

    Gio

  • Hi Giovani

    Thnanks for your help and for your prompt reply.

    Please i'm looking for a TIDA-00663 software , is there any SW that can help me and from which i can take insoiration to write my own code.

    I saw in the discussions that you recommanded getting the  TDC7200EVM.I got it and i found only the configuration of the TDC7200, what about the other desing's parts.

    Thanks again.

    Yasmine 

  • Hi Yasmine,

    The only software that we offer is the one pointed out in this thread:

    https://e2e.ti.com/support/sensors/f/1023/t/675419?tisearch=e2e-sitesearch&keymatch=tida-00663 

    Thanks

    Gio