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TDC7200: TRIGGER UPDATE FREQ in GUI tool

Oba
Genius 15770 points
Part Number: TDC7200

Hello

My customer is evaluating both TDC7200EVM and TDC100_C2000 EVM and have a question for both GUI tools.

There is "TRIGGER UPDATE FREQ" box in both tools and  100msec is the minimum configurable value.


Is there any way to configure less than 100msec?

Regards,
Oba

  • +1
    TI__Mastermind 21770 points

    Hey Oba,

    Thanks for reaching out on the forum. Unfortunately we do not presently have a way to configure the GUI to have "TRIGGER UPDATE FREQ" below 100msec.  Despite the GUI limitation, you could program a microcontroller to trigger after INT B is asserted.  Then your trigger update would only be limited to the start to stop duration specification and your communication to device speed.

  • 0 in reply to Patrick Simmons
    TI__Genius 15770 points

    Hello Patrick,

    I have an additional question related to this topic.
    Is it possible to realize 1msec trigger update frequency in customer's own system (I mean the host MCU)?
    What is the minimum trigger update frequency as a device?


    Regards,
    Oba

  • +1 in reply to Oba
    TI__Mastermind 21770 points

    Hello Oba,

    The minimum trigger update frequency depends upon multiple variables.  One variable would be the clock speed chosen for the spi communication.  Looks like the TDC7200 is limited to 20MHz.  I presume you would need to perform a read and write for gathering the measurement data and for starting the next set of measurements.  This would translate to a minimum of 1.6us (1/20MHz*(16periods for write + 16 periods for read)), which is well under 1ms.  But as alluded to, this duration will become longer with a slower clock frequency.  The next and more significant variable would be the measurement mode and number of stops you configure for.  For measurement mode 1, max time between start and last stop is 500 ns.  However, for measurement mode 2, that max time between start and the last stop could be (2^16-2)*(1/16MHz)=4ms.  Slower clock setting will result in even longer duration.  As for the latency from any mcu that communicates with device, that will depend on the clock frequency it is operating on.