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Questions related to PGA450Q1EVM-S operation.

BJ Han
Expert 2035 points

Hi, TI engineer

PGA450Q1EVM-S board is in use and refer to sldu019b.pdf (PGA450Q1EVM-S User's Guide).
2.3 UART When receiving data using Command1, Command4, etc. in Command List, it looks like a random value and it seems that data output proportional to distance does not work.
(The same symptom of two modules)

(Power is 9-12V DC, UART 19200BPS is used)

One more thing to check is that I wonder if this EVM board does not have a DACO (PIN 16) output at the factory.

  • 0
    TI__Genius 16030 points
    Hi BJ,

    I've assigned this post to the appropriate applications engineer, he will respond to your question.

    Regards,
    Karl
  • 0
    TI__Mastermind 27780 points

    Hi BJ,

    To ensure your UART communication settings are configured properly, have you confirmed if command0 returns a value of "0x12 0x34 0xB4"?
    Your voltage supply and UART baud rate are OK.
    What value does command1 return? Please list the hex result you have concerns for, and the expected/targeted distance (in meters). Here is an example of how to convert the 16-bit hex return to a distance equivalent:

    Parameter

    Value

    Units

    TOF (Hex) (0x MSB LSB)

    16A3

    VOID

    TOF (Dec )

    5795

    VOID

    TOF (seconds)

    0.005795

    s

    Speed of Sound through Air (343.1m/s) /2

    171.55

    m/s

    Distance (meters)

    0.99413225

    m

    Distance (feet)

    3.261588851

    ft

    Distance (inches)

    39.13906621

    in

    To calculate distance, consider the following formula:
    Distance in meters = (Speed of Sound Through Air) * [((TOF in decimal)/1000000)/2]s
    where:
         •TOF = Time of Flight = 0xMSBLSB (MSB at AddrD3 (TX_DATA0), LSB at AddrD4 (TX_DATA1))
         •Speed of Sound Through Air = 343.59m/s
    For example: 0x0378 in hex is 888 in decimal, thus,
    Distance = 349.59m/s * [(888/1000000)/2]s = 0.155 meters
    This calculation is explained in the “Demo write up for use with Firmware Rev 2.1_B.pdf”

    The DACO pin is routed to pin J4-1, but the test mode is not enabled in the OTP example provided.