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DAC088S085 Spi Interface

Prakash BJ
Prodigy 80 points
Other Parts Discussed in Thread: DAC088S085, WAVEVISION4

Hi ,

I have recently bought DAC088S085. I am facing problem with it.

I am writing it in WRM mode & then WRT mode. But the output on the output pins remain low.

Can any one help out?

Thanks ,

Prakash BJ  

  • 0
    TI__Intellectual 2630 points

    Prakash, A few questions to help debug your issue:

    1) Are you using a DAC088S085 evaluation board with WaveVision4 software? If not can you please share your schematic.

    2)  For one of the channels can you explain what do you expect to see (what have your written to the chip) along with a snapshot of scope traces for SYNCbar, SCLK, & DIN.

    3) Is there a chance you have placed the device in power down mode?

  • 0 in reply to Jason Seitz
    Prodigy 80 points

    Hi Jason Seitz,

    Thanks for ur interest.

    1) I am not using the evaluation board & the S/W u have mentioned.Below is the schematic of it

    DOUT & SCK has been pulled high to 3.3V via 4.7K & SYNCbar is pulled high to 5V via 10k.

    2)Below is the Timing diagram of SPI Lines.

    Yellow Line - > SCLK

    Blue Line -> DIN

    Purple Line -> SYNCbar

    3)What is meant by power down mode ?

    Thank you,

    Prakash BJ 

  • 0 in reply to Prakash BJ
    TI__Intellectual 2630 points

    Prakash,

    The DAC088S085 is a SPI interface device. Unlike I2C interface SPI doesn't require pull up resistors. Please remove these resistors and retest.

    Power down mode is a feature which allows for power savings. In this state the output amp of the DAC channel would be off and the output would be terminated to Hi-Z, 100kohm to ground, or 2.5kohm to ground. See POWER-DOWN MODES section on page 19 of the datasheet for more information.

  • 0 in reply to Jason Seitz
    Prodigy 80 points

    Hi Jason Seitz,

    I finally got the DAC088S085 working in WTM Mode. With the pullups present .

    Regards,

    Prakash BJ