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Original question:

PGA970: 14-bit DAC look-up table (LUT)

PGA970: DAC output in reset mode

carmine ricca
Prodigy 150 points
Part Number: PGA970

Hi Scott

I would like to acquire PGA970 DAC output while the device is in reset mode. I configured the following registers:

ALPWR, DAC_CTRL_STATUS, OP_STAGE_CTRL, DAC_CONFIG, OP_STAGE_CTRL, AMUX_CTRL, DAC_LPBK_CTRL accordingly to 7.5.7 and 7.5.8 of SLDS201A January 2016 rev Dec 2016.

While via SPI DEMOD1_DATA and DEMOD2_DATA are available and consistent, but PGA970 DAC Ratiometric Analog Output is always about 0 Volt.

Please have you any suggestions?

Thanks Carmine

  • 0
    TI__Mastermind 31655 points

    Hello Carmine,

    Without using M0 firmware there is nothing that connects the DEMOD outputs to the DAC internally. If you have the DAC configured correctly, you will be able to manually control the output by writing DAC codes to the DAC_REG0_x registers. If you do not use internal firmware you will have to take in the demodulator data externally, then use an external source to write DAC codes to the DAC registers through one of the digital interfaces.

    Regards,

  • 0 in reply to Scott Cummins
    Prodigy 150 points

    Hi Scott

    Your post clarifies how the Analog Ratio/absolute output works. From datasheet unfortunately that information isn't reported: it seems that you can use the DAC also when you are in reset. 

    Thank you

    Carmine