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DAC81408EVM: DAC EVM output is not responding

Che-Ming Hsu
Prodigy 10 points
Part Number: DAC81408EVM
Other Parts Discussed in Thread: DAC81408, AM2634

Tool/software:

Hi, 

I have got a DAC81408EVM, and I try to control it by the SPI from my Arduino.

Here's my setting

VCC = 10V

VSS = 0V

VDD/VAA and VIO is 5V (J10 selection = VIO)

1. I have tried to read 0x03 and I can get the correct value 0x0A24

2. following initial process

Write  SPI_CONFIG(0x03)      0x0A84

Write  DEV_PWDOWN(0x09) 0xF00F

Write  GENCONFIG(0x04).     0x7F00

3. Write DAC0(0x14) 0x00FF

but the output(measure at R6) is still 0V

I also read each register after I program it. I found that 0x04 becomes 0x0400. Is it correct?

I read similar question in old thread, but discussion moved to mail.

https://e2e.ti.com/support/data-converters-group/data-converters/f/data-converters-forum/1057048/dac81408evm-dac81408-output-is-not-responding?tisearch=e2e-sitesearch&keymatch=DAC81408#

best,

Daniel

  • 0
    Prodigy 10 points

    Typo I measure the DAC0 output at R3, not R6.

  • +1 in reply to Che-Ming Hsu
    TI__Intellectual 2640 points

    Hi,
     
    There is minor mistake in the data sheet.
    As per DAC81408 data sheet, OUT[0:3]/OUT[12:15] are not available and they are NC pins. EVM's OUT[4:11] are OUT[0:7] of DAC81408 device. As you can see in the pin diagram ().   

    In DAC81408EVM user's guide - 

     - EVM schematic OUT4 is OUT0 of DAC82408 device (address 0x14). 
     - EVM schematic OUT5 is OUT1 of DAC82408 device (address 0x15).
    ...
    ...
    ...
     - EVM schematic OUT11 is OUT7 of DAC82408 device (address 0x1B).

    Please use the above details and let me know if you still face issues related to anything.
     
    Thanks,
    Sanjay

  • 0 in reply to Sanjay
    Prodigy 10 points

    Hi Sanjay,

    Cool, it works perfectly! Thank you very much!

    best,

    Daniel

  • 0 in reply to Sanjay
    Prodigy 50 points

    Hi Sanjay,

    First of all, I would like to thank you for your time and support over call to solve my problem.

    Problem: Not Able to communicate with DAC81408.

    Summary:

    I was interfacing DAC81408 with AM2634 Quad Core Controller over SPI0 and setup to Core 0. I was not able to get any response from DAC81408.

    I have already scrolled E2E Chat Support and Setup my code based on given (your) response.

    Once the first call done with you, I was able to establish the communication but not able to get expected value. then multiple rounds of extensive discussion with you and datasheets reading, schematic understanding, Power supply checking, was able to get narrow down the problem. Finally, you point out that check proper ground connection and SPI Communicaton waveform check as per datasheets. I found that my PICOSCOPE(Probe) was drawing the current and voltage. Due to this my SPI Communication was not proper and DAC Output was not proper. Once I removed the Probe from my circuit everything started working as per expected.

    Once Again, A Big thanks to you Sanjay for listening our problem and giving resolution.

    Regards

    Aman