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DAC8750 not working

Nitesh Padiyar77
Genius 3745 points
Other Parts Discussed in Thread: DAC8750, MSP430F5659

Hi,

I am working with DAC8750 using SPI comm. through MSP430F5659. My SPI is working fine and it is tested well.

I am able to up the DAC but always shows same current value.

Here are my routine to init and set value

// write the reset command

// write the NOP command

// write the control, configuration, gain and zero calibration register

control register is set to OUTEN and IOUT range 101(4-20ma), Configuration register set to 0x0000, Gain calibration Register set to 0x8000 and Zero calibration register set to 0x000

then

// write the data register with value 0x7FFF and 0xFFFF

Both time current output is not changing. 

***Even before writing OUTEN bit of control register is cleared and tried writing DAC count value in write data register after and before setting OUTEN bit of control register write.

Any thing i am missing while writing please comment, its very urgent.

Nitesh

  • 0
    TI__Genius 10615 points

    Hi Nitesh,

    I have a few questions for you.

    • Are you enabling the internal reference or are you providing an external reference?
    • Are you able to readback from the DAC?
    • Do the registers display the values that you are expecting? If you are having trouble reading back from the DAC, you can just share with me an oscilloscope capture of one of your SPI transactions and I can verify that the interface is behaving as the DAC expects.
    • What is the load at the output?
    • What supplies are you using?
    • If you can share a snippet of your schematic I can do a quick check on that as well.

  • 0 in reply to Eugenio Mejia
    Genius 3745 points

    • Are you enabling the internal reference or are you providing an external reference?

    Using internal Reference configured through hardware- refer schematic

    • Are you able to readback from the DAC?

    Yes

    • Do the registers display the values that you are expecting? If you are having trouble reading back from the DAC, you can just share with me an oscilloscope capture of one of your SPI transactions and I can verify that the interface is behaving as the DAC expects.

    Yes

    • What is the load at the output?

    115 Ohms

    • What supplies are you using?

    24V

     

    Schematic :

  • 0 in reply to Nitesh Padiyar77
    TI__Genius 10615 points

    Nitesh,

    The schematic does not seem to have attached correctly. Can I contact you to your E2E registered email to get the attachment?

    Nitesh Padiyar52 said:
    Using internal Reference configured through hardware- refer schematic

    If you are using the DAC internal reference, it must be enabled through software.

  • 0 in reply to Eugenio Mejia
    Prodigy 60 points
    Hi Eugenio,

    Nitesh is on leave for couple of days, could you please send a test mail on " sandeepkumar.sharma@in.abb.com ", so that I can send the attachment of schematic.

    Regards,
    Sandeep Sharma