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DAC8560: DAC8560 Interfacing with Laptop via USB (USB to SPI Adapter)

Sheldon Maciel
Intellectual 400 points
Part Number: DAC8560


Hello,

I am wanting to interface the DAC8560 to my laptop via USB. I was thinking of using some sort of USB to SPI adapter like this one: http://www.ftdichip.com/Support/Documents/DataSheets/ICs/DS_FT232H.pdf.

I am having trouble figuring out how to interface the /SYNC pin on the DAC8560 to the FT232H. I understand that SCLK is SCK and DIN is MOSI, but what would /SYNC be for the standard SPI wiring (MISO, MOSI, SCK, /SS)? Would /SYNC just be /SS? I may also want to add a second channel in the future and I can see I can do that with the EVM, so I am looking for something that would accommodate this requirement as well.

Thanks,

Sheldon

  • 0
    TI__Mastermind 46290 points
    Hello Sheldon,

    The /SYNC pin can be treated as the chip select, /CS, or slave select, /SS, for the DAC8560 "SPI Compatible" interface.

    Most often when interfacing multiple devices on an SPI bus a GPIO pin becomes the /CS pin as a typical SPI peripheral does not include multiple built-in /CS pins. For similar purposes in our labs I use a NI USB-8452 or one of the NI PXI Multifunction I/O Modules.
  • 0 in reply to Kevin Duke
    Intellectual 400 points
    Thanks very much Kevin for your quick response!

    I don't have the DAC8560 in hand to confirm, but I assume this resolved my concern.

    Thanks for the suggestion for the NI product.

    So I'm assuming I can just use spare GPIO pins on an MCU/MPU to interface with the DAC so I can use almost an unlimited amount of DACs?

    Have a great day,
    Sheldon
  • 0 in reply to Sheldon Maciel
    TI__Mastermind 46290 points
    Sheldon,

    No problem.

    Yes - generally speaking one would use a GPIO from an MCU as the CS signal when implementing multiple SPI devices on a shared bus. Theoretically this could be many DACs, the main limitation would become being mindful of the digital input capacitance (3pF max) which could start to stack up and interfere with timing with an extreme number of devices on the bus.
  • 0 in reply to Kevin Duke
    Intellectual 400 points
    Thanks! So many things to consider!