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ADC08DJ3200EVM: ADCxxDJxx00 SPI Pins

Part Number: ADC08DJ3200EVM
Other Parts Discussed in Thread: LMK04828, LMK04832

Tool/software:

Hi there,

We have a couple of TI’s ADC eval boards.  The ADCxxDJxx00  User’s Guide describes how to set up the ADC using the TI GUI software.  We would like to tie into the SPI pins on the ADC and set up the ADC directly.  Is that supported?

Thank you!
Kara

  • Hi Kara,

    This ADC is not configurable by using the spi pins as bootstrap options. A SPI interface and register writes are required to operate this device.

    Chase

  • Hi Chase,

    Thanks for the quick follow up! To clairfy, we would like to drive the spi interface on the ADC directly from an FPGA development board we have.  Is there a place on the TI module that we can connect to the spi pins?

    Thanks again!

    Kara

  • Kara,

    On this EVM it will not be straightforward but it is possible. It will require removing resistors R133-R136 and soldering wires across each resistors pad. The most important thing however if the customer plans to do this is to know that these are connected directly to the ADC meaning there is no level shifter between this point and the ADC. The SPI which is injected into the wires MUST meet and not exceed the correct SPI levels for the ADC (0-1.9V). This may require using an external level shifter evaluation board/etc. If the signals injected onto these spi wires are above the tolerable levels for the ADC, then damage may occur.

    The customer will also need to control the LMK04828 as well, which requires the same resistor removal process but for R118-R120, R178. These are also connected directly to the LMK device and thus the spi must be at device logic level for the LMK04832 (0-3.3V). The SPI signals passing into this device must adequately meet the VIH and VIL requirements for the device, otherwise it will not behave properly.

     Chase