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DAC80504EVM: DAC80504 becomes unresponsive after changing state of pin in EVM software

Part Number: DAC80504EVM

First, glad to see that TI is shouldering support on it's customers and web-forum.

I was using the DAC80504EVM to find a set of register values I could use to initialize the device for my application. I did this and had gotten everything configured short of actually enabling the outputs, with the registers returning believable values, etc., when I decided on a whim to see what changing the state of the hardware pins in the software did. So, I changed RSTSEL to HIGH. All of the registers returned all 1s (0xFFFF) when I performed either a Read All or Read Selected, confirmed by my logic analyzer. Ooops. So, I set RSTSEL back to LOW. I have never been able to get a believable register read out of the device since. I have tried shutting everything down, disconnecting, and reconnecting and re-launching the software, without success. Is there anything I can do to restore functionality? I really need this device to work.

  • Hi Warren,

    What is the position of all the jumpers on the board?

    Thanks,
    Paul
  • The jumpers are in the out-of-box configuration.

  • Hi Warren,

    Please try to following debug steps:
    1. Connect the USB2ANY, supply the VDD voltage, and start the GUI software.
    2. Note the voltage on VIO (TP8), VDD (TP6), LDAC, REFDIV, RSTSEL, and GAIN (pin 1 of JP2, JP4, JP5, JP6)
    3. Measure the voltage output of the 4 dac pins.
    4. Set the RSTSEL pin through the software and power cycle the DAC by removing VDD momentarily - measure the DACs again.
    5. Can you read the DEVICE ID register? What do you read?

    thanks,
    Paul
  • Well, this is confusing, and the end of this journey. It wasn't clear from the EVM user's guide if VDD needed to be supplied separately if the VIO jumper to 3v3 was used (TP8). I jumpered TP8, tested for voltage with my 'scope and found 3.4V at VDD and VIO. When I ran the software, it initially worked in this configuration, I even had DAC output. When I tried it again a few days later was when I had trouble. But, if I jumper VIO to VDD, everything works again, leaving me to conclude that there must have been a hairline short, or something like it that allowed me to to jump in and use the board when VDD was not properly supplied.