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DAC60004: DAC60004 not responding

Kent Iverson
Prodigy 10 points

Part Number: DAC60004
Other Parts Discussed in Thread: DAC63004WCSP-EVM, DAC63004W, DAC63004

Hi, 

We have a fairly simple design based around a Nordic nRF54L15 SoC paired with a DAC60004 and connected via the I2C interface.  The interface is of course, very simple being SDA/SCL/VDD/GND. 

We brought up our firmware using the Nordic nRF54L14DK evaluation board and the DAC60004 EVM and with proper jumpering on the DAC EVM (USB disabled), I2C selected, we were successful with bringing up the application with full DAC operation at the default I2C address (0x48).

We then moved to the prototype boards with our circuit design and we find no connectivity with the DAC.  The SDA line is asserted low at the START but no data is emitted and no clock appears on SCL.

The circuit differences between the DK/EVM and our prototype are that the A0 line is held low instead of high (address 0x49), The GPIO line is being held low through a resistor, and the SDA/SCL lines are connected to two different pins on the nRF54L15.   The firmware loaded on the prototype targets the new SCL/SDA pins. 

We have confirmed connectivity and termination of the SDA, SCL, VDD, and GND connections on the prototype board for the DAC and the nRF54L15 and are atPatch_nRF54L15_schematic.png a loss as to why this basic connection is not functioning. Patch_DAC60004_schematic.png

We are attaching the nRF54L15 and DAC60004 portions of the schematic for reference and would appreciate your review and guidance as to what could be blocking this basic connectivity issue.

  • 0
    TI__Mastermind 24455 points

    Hi Kent,

    The DAC63004 product page says that this device only supports SPI communication, not I2C. However, the DAC63004W does support I2C, which should be the device found on our DAC63004WCSP-EVM.

    1) What was the EVM you used for early testing?

    2) What was the top marking of the device on the EVM?

    Regards,

    James

  • 0 in reply to James Steenbock
    TI__Mastermind 24455 points

    Kent,

    I see you added the EVM name to the thread information, DAC63004WCSP-EVM.

    I think the part on the EVM and the part you have on your board are slightly different. The one on your board is the version without I2C functionality.

    See if swapping to the DAC63004W fixes the issue.

    Regards,

    James

  • 0 in reply to James Steenbock
    Prodigy 10 points

    Hi James,  Thank you for the followup.  

    First, thank you for correctly assuming I was referring to the DAC63004 device.  I was typing too fast and dropped it in the case title and problem description.

    Second, I am confused regarding the product specification and your comment suggesting the part we are using is SPI only. The part number for the device we are using is the DAC63004RTER.  The TI data sheet for the part (https://www.ti.com/document-viewer/DAC63004/datasheet) says nothing about being SPI only and if fact is titled "DACx3004 12-Bit and 10-Bit, Ultra-Low-Power, Quad Voltage and Current Output Smart DACs With Auto-Detected I2C, PMBusTm, or SPI".  This happens to be identical to the DAC63004W with the difference being that the DAC63004RTER is a WQFP package and the DAC63004W is a BGP package. Obviously swapping from the WQFP package to a BGP package isn't trivial and requires a new layout and differences in board assembly.

    It seems that a key feature of the DAC63004 component is the variety of digital interfaces available.  

  • 0 in reply to Kent Iverson
    TI__Mastermind 24455 points

    Hi Kent,

    Apologies, I checked the linked device at the top of the thread, but it was a link to the DAC60004 which is SPI only. I thought that was a link to the DAC63004.

    Your pull-up configuration seems fine, and the only other visible connection is tied to the host pins. You mentioned that SDA is going low for a start condition, but you don't see any data or any clock.

    Are both I2C lines held high after power up, but before any commands are sent?

    After SDA goes low, does SCL also toggle low? Or does it remain high?

    The start of the I2C command is handled by the host, and all you should need are some pull-ups on the I2C lines for the open-drain control to work.

    Regards,

    James