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PGA460: How much maximum sensor can interface with PGA460 ?

Haresh Prajapati
Prodigy 210 points
Part Number: PGA460
Other Parts Discussed in Thread: ENERGIA,

Hello All,

We have 8-ultrasonic sensors and want to interface with Beagle bone black wireless.

So my question is "PGA460" can interface interface more then 1 sensor. 

If yes then what will the solution?

 

  • 0
    TI__Mastermind 27950 points
    Hi Haresh,

    Yes, the PGA460 device contains a three bit UART_ADDR field to support up to eight devices on a single bus.
    There are three communication interfaces you can use on a bus:
    1. UART (TXD and RXD pins)
    2. USART-SPI (TXD, RXD, and SCLK pins)
    3. OWU (IO pin)

    UART and USART-SPI are low logic level interfaces that can support either 3.3V or 5V levels. UART supports speeds up to 115.2kBaud, while USART-SPI supports speeds up to 8MHz. USART-SPI does not require a traditional SPI chip select pin since the device address is embedded in the USART-SPI command. Either of these two interfaces will be most applicable with a Beagle Bone.

    One Wire UART (OWU) is intended for automotive systems since this is a battery level referenced communication interface (6-30V). The protocol is identical to UART, and is intended to be a LIN-alternative.
  • 0 in reply to Akeem Whitehead
    Prodigy 210 points

    Hello Akeem Whitehead,

    Thanks for your input,

    Is there any sample code available which can interface more then one sensor interface in single bus with any device.

  • 0 in reply to Haresh Prajapati
    TI__Mastermind 27950 points
    Hi Haresh,

    Yes, sample code is available to evaluate multiple PGA460 devices on a UART or OWU bus. The example code is available is an Energia sketch called the busDemo.ino in the "PGA460 Energia Library and Code Example" zip at: www.ti.com/.../slac741

    You will need to EEPROM program the 3-bit UART_ADDR value of each PGA460 device to a different value before connecting them to the bus to run this sketch.
  • 0 in reply to Akeem Whitehead
    Prodigy 210 points

    Hello Akeem Whitehead,

    Thanks you for provide sample code.

    We have only one question that does this attached sensor will work with this IC ?

    KQ112KH.pdf

  • 0 in reply to Haresh Prajapati
    TI__Mastermind 27950 points
    Hi Haresh,
    Unfortunately, this KQ112KH transducer cannot be supported by the PGA460 due to its center frequency of 112kHz. The PGA460 only supports transducers with a resonant frequency between 30-80kHz and 180-480kHz.

    I recommend that you filter through the PGA460: Air-Coupled Ultrasonic Transducers & Transformers Listing spreadsheet available at:
    e2e.ti.com/.../620399

    You should be able to find an equivalent alternative based on your preferred transducer specifications.
  • 0 in reply to Akeem Whitehead
    Prodigy 210 points

    Hello Akeem Whitehead,

    Thanks for your reply.

    This information very help full for us.

    Once again thank you very much.

  • 0 in reply to Haresh Prajapati
    Prodigy 210 points
    Hello Akeem Whitehead,

    We are planning to buy EVM of PGA460-Q to interface.
    We are also planing to buy ultra-sonic sensors with a resonant frequency of 40 kHz.

    We have still query regarding hardware interface that how we can interface 8 sensor with single board.

    is there any special circuit required for hardware connections?

    So kindly share us some reference data if possible.

    Thank You
  • 0 in reply to Haresh Prajapati
    TI__Mastermind 27950 points

    Hi Haresh,

    If you are purchasing the PGA460-Q1 EVM, then you do not need to purchase any additional hardware to enable an 8-PGA460-device bus configuration.

    The PGA460-Q1 EVM has a UART bus, a SPI bus, and a OWU bus-transceiver you can leverage with the Energia example code mentioned earlier.

    However, if you are trying to use a single PGA460 to mux/demux multiple sensors, then refer to the following discussion page:

    https://e2e.ti.com/support/sensor/ultrasonic/f/991/t/603257

    If this is your goal, then you will need additional hardware as specified in this E2E app note to switch between each sensor. This solution has only been tested with a half-bridge driver since transformers require more power compatible switches. If you do not need to switch between each sensor, and instead burst+listen all sensors simultaneously, you do not need any additional hardware; however, you will not be able to differentiate the sensor return data.