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TDC7200: Is there a way to connect TDC7200 EVM board to a xilinx FPGA ?

Foram Shingala
Prodigy 130 points
Part Number: TDC7200
Other Parts Discussed in Thread: TDC1000

I'm currently using TDC7200 EVM with Arduino UNO and a opensource SPI commands c library for communication between TDC7200 IC, Arduino and PC.

We give START and STOP signals directly to TDC7200 EVM board (not through Arduino).  Arduino is only used to communicate with the PC and output TOF values.  The TOF value is relative to the internal clock of TDC7200. What we now require is TOF  value with reference to an external clock to obtain absolute timestamp.

How can this be done?  Can we use TDC7200 EVM with an FPGA ? as an external clock with frequency other than 8MHz or 16MHz to Arduino would require change of crystal.

Is there an opensource SPI library available for communication with an FPGA.  or can the external clock input be used to derive the required information.

I've attached the TDC7200 SPI c library. TDC7200.hTDC7200.cpp

  • 0
    TI__Genius 11015 points
    Foram,

    The TDC7200 device typically received the START & STOP signal from a Ultrasonic AFE (like TDC1000) and counts the time difference between the 2 signals using an external clock as reference. This clock signal can also be provided by any MCU. We do not have any SPI library for communication with FPGA.
  • 0 in reply to Bharat Aravamudhan
    Prodigy 130 points

    Thank you for the response.

    Bharat Aravamudhan said:
    time difference between the 2 signals using an external clock as reference.

    Can we provide any frequency external clock? Is there a limitation on the frequency of the external reference clock?

    Also is it possible to run a coarse counter on the external reference clock and obtain at which clock pulse has the measurement of  TOF been made. As multiple reference clock pulses are skipped waiting for an event.

    We require the absolute timestamp of occurrence of and event along with the time of flight value.

    Is there any attribute, which is used to calculate TOF, from which this information can be derived ? clock count?

    In mode 2 time(1) - time(n+1) gives tof. What exactly is this time(1) value?

  • 0 in reply to Foram Shingala
    TI__Genius 11015 points

    Foram,

    We recommend we use external clock frequency of 1 to 16Mhz. Also as the clock freq increases the Std deviation decreases. We actually recommend you use 16Mhz which has the least std deviation.

    The coarse counter can be run based on the external clock however the accuracy is better when we use internal clock.

    Please refer to the section 8.4.2.2 to understand the mode2 of application of TDC7200 and how to calculate the ToF