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PGA302: PGA302 dac_ctrl_status

Ruben Khazhakyan
Prodigy 20 points
Part Number: PGA302

Hello,

The datasheet of PGA302 in section 8.3.16 states the following:

        "The DAC can be disabled by writing 0 to DAC_ENABLE bit in DAC_CTRL_STATUS register.".

I couldn't  find the DAC_CTRL_STATUS register neither in the  register map nor throughout the entire document.

This register mentioned only once in the statement above.   I use SLDS216 –DECEMBER 2017 version, recently downloaded

from TI product page.  Please, any comments.

        Regards,

Ruben

  • 0
    TI__Mastermind 31655 points

    Hi Ruben,

    The DAC_CTRL_STATUS register is DI page 0x2, and offset 0x38. The DAC_ENABLE bit is bit 0. While it is possible to control this bit while in digital interface mode to enable/disable the DAC, there is no way to disable the DAC while the PGA302 is in compensation mode, so I believe the original intention was for this register to be unused in the PGA302. I will make sure the datasheet is changed to reflect this in the next update.

    Regards,

    Scott

  • 0 in reply to Scott Cummins
    Prodigy 20 points

    Hi Scott,

    I came to this question while playing with PGA302 GUI, though without EVM board. Just opened "PGA302 Linearity Calibration" page , set communication interface to I2C and clicked START.  In Data Log window  the two write commands were issued:  0x42 0x38 0xE9  and   0x42 0x67 0xE9.   My assumption was that the first write is DAC_ENABLE bit set .  Not sure what is write to offset 0x67. 

    So, GUI still uses DAC_ENABLE bit.  From your answer I didn't get if DAC_CTRL_STATUS  still exists in the hardware and accessible via DI. If it exists I would like to have a full description of the other bits, if possible.  In the future I plan to design own calibration board, thus I'd like to know about internals of PGA302  as much as possible.   

    Thank you for support.

    Ruben 

  • +1 in reply to Ruben Khazhakyan
    TI__Mastermind 31655 points

    Hi Ruben,

    The DAC_ENABLE bit is technically useable, but is not needed for the PGA302, and it will be removed from the datasheet. The GUI was made to support additional parts that are yet to be released, and the datalog commands that you have noticed were intended to work with both the PGA302 and these other parts, so some additional commands not needed for the PGA302 are included for simplicity in the GUI's coding.

    Regards,

    Scott