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DAC161S997EVM. Programming DAC through SPI with OFF-board uP

Other Parts Discussed in Thread: DAC161S997EVM

Hi.  I have some more questions related to the DAC161S997EVM.  It was suggested to me that the board can be programmed with a different, off-EVM microcontroller.  I am in the process of trying to teach a 28069 to program this board.  Now that I am working with the EVM, I have the following questions:

1.  I understand that, as delivered, the DAC_CUR1 / VDD jumper is set to power the device from the current loop. All good. Is there a way for me to test in "Self Powered Transmitter" mode, i.e. where the loop is not powering the DAC logic?

2.  How can I tie in an external uP, through J3, to program the DAC?  I was led to believe this was possible but (a) am worried about conflict with the on-board uP and (b) do not see how I control CSB through J3 or any other obvious means.

3. Comment: The DAC_CUR1 / VDD jumper silk screen is confusing. I would change "VDD" to "VDDA", as "VDD" is confusing because it is the same label as the "digital" side power.

Thank you.  I had a couple of other questions that were answered by cruising the forum.  Good stuff!

John 

  • Hi John,

    Sorry to bring up this old thread, but I am running into the same issue (#2) with getting access to the CSB.  Did you end up finding a solution to this?  Were there any conflicts with an off-board microcontroller?

    Thank you,

    Brian

  • Hi Brian.  I am jogging my faulty memory...but here is what I remember:

    1. I determined, either through the forum or tech support at TI, that one could NOT use an external microcontroller with the eval board.

    2. I used the eval kit tools to poke at the DAC and better learn how it ticks.

    3. I then had a prototype web site place the DAC on a break-out board, replicated the eval unit circuit, and got it running with my 28069.  It was a bit of a bear to get it running with the 28069, but I've detailed how I achieved that in another forum thread.  Search on the part number if interested.  If you can't find it, let me know and I'll dig it up.

    Good luck!

    John