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TSW14J56EVM: Specifications of external trigger signal

Part Number: TSW14J56EVM

Dear all,

Hi.

According to the TSW14J56EVM user guide, the external trigger signal (TRIG_IN) is an " Adjustable level CMOS trigger input. Default level is 1.8 V".
May I ask for some explanation? What is the specification of the signal that the data capture card accepts as an external trigger in order to start data capture?

Thanks.

Fernando

  • Fernando,

    The external trigger uses a voltage level translator for the signal the is routed to the FPGA. The input side of this device has an adjustable voltage that allows the device to operate with 1.4V to 3.6V range. The supply that controls this voltage is U32. Switch SW10 is used to set this voltage. The output of the device is fixed. Just set the switch so the part handles the level of the input trigger signal you are providing.

    Regards,

    Jim 

  • Dear Jim,
    Thank you so much.

    I'm sorry for my naive question. What about the type of the signal? Is it possible to use, for example, a DC signal for triggering?
    If yes, what about other specifications of the signal (like bandwidth in case of an AC signal)?
    Is signal voltage the only important parameter?

    Thanks.
    Fernando
  • Fernando,

    The signal goes to the 'B" port of a SN74AVC2T245, with the voltage of this port set by the value of VAR. See the device data sheet regarding input signal allowable conditions.

    Regards,

    Jim