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DAC3171 with Incorrectly Programmed Fuses?

John Glett
Prodigy 70 points
Other Parts Discussed in Thread: DAC3171

I've been struggling for the past week with an issue where I've been attempting to get a DAC3171 working in DDR mode with an Artix 7 FPGA.  The DAC appears to be rejecting the lower 7 bits.  While going through the registers with a fine-tooth comb, I noted that the readback after power-up on register config 6 (0x06) is reading back 0x0090 instead of 0x0010 as it should for a DAC3171.  The fact that bit 7 is set, according to page 43 of the latest datasheet, indicates that the device is locked to use only 14-bit full interface mode, and can't be configured to use the 7-bit DDR interface mode. The other registers read back properly, so I'm pretty confident in my SPI interface reading the register correctly. 

I can't find any reference to there being a version of the DAC3171 that only supports 14-bit mode, but the device I have certainly seems to be fused that way, and is acting like it.  Is it possible that that fuses were mis-programmed from the factory for this batch??? 

  • 0
    TI__Mastermind 29220 points

    John,

    I believe our quality manager has been in contact with you personally about this issue and to get new devices into your hands.  I just now noticed that this forum posting has been sitting here 'unanswered' all this time, however.   Has he gotten new production devices to you by now?

    Regards,

    RIchard P.

  • 0 in reply to Richard Prentice
    Prodigy 70 points

    Richard,


    Thanks for getting back with me.  I have been working with Bernard, but he didn't seem to be having a lot of success finding parts and I haven't heard back from him for some time now so I'm not sure if he's on vacation or what.  Our project is about 6 weeks behind schedule now due to this issue, and I still can't get a straight answer on where I can even order parts that are known to be good.  Any assistance you can offer at this point would be appreciated. 


    Thanks,

    John

  • 0 in reply to John Glett
    TI__Mastermind 29220 points

    Hi,

    I am sorry to hear that and a bit surprised as well.  I know Bernard is in the office and tells me he will be trying to contact you today.   I think the problem has been that in ordering new devices for you he wants to be sure that if there are still some old stock out there that shouldn't be there he doesn't want to have *more* old stock get to you and exacerbate the situation.  But new material is available.  Bernard is still trying to find out *why* there was old stock out there when there should not have been. 

    Regards,

    Richard P.