AD2S1210 data bits in hi Z?

I am trying to get the AD2S1210 working in a project.  I am able to power it up and see the excitation at the default 10Khz.  I have a microprocessor that I've got running to program the ADS1210.  When that microprocessor is not connected to the AD2S1210 it seems to run fine.  When it's connected to the AD2S1210, I don't ever see the data bits changing (I've got it running in parallel mode; DB7-DB0 just sit at zero).  I have CS tied to ground on the AD2S1210.  A0 and A1 are set at 1 to put it in configuration mode.  Is there another enable or something else I need to do in software?  I'm wondering if the data bits are in high impedance mode because I've missed something.

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  • 0
    •  Analog Employees 
    •  Super User 
    on Apr 13, 2021 4:54 PM

    nxg67djh356,

    Can you please answer the following questions for me with regards to your setup.

    1) Can you please indicate for me which signals you are controlling with the microprocessor when connected?

    2) When do you see the change in behavior between the unconnected and connected condition?   Is it after you write to the memory? 

    If you are in configuration mode what is the last address you write to the memory in that sequence?  

    3) can you please share a timing diagram (either hand drawn or scope/LA capture) of what your timing looks like in the connected case?

    4) How are you powering up the data interface (VDRIVE) when disconnected versus when you connect the micro?

    With a little more information I should be able to help you sort this out.

    Sean

  • 1) I am controlling DB7-DB0, A1,A0, RD, and WR with the microprocessor.  A1, A0, RD, and WR seem to be working.

    2) I'm essentially just checking voltages after the configuration stuff finishes writing.  With the microprocessor unconnected, I can see DB7-DB0 set to 0x76 (it's the data word for a control word 0x92 write).  Connected, DB7-DB0 are all zero.  I've put a scope on some of them and they don't appear to be changing during the configuration period.  Right now I've actually commented out doing any configuration writes to try to simplify.  I just set A1,A0,RD,WR and DB7-DB0.  I'm not even latching the data bits with WR so I am assuming I should be able to see the DB7-DB0 the micro puts out and they are not changing.

    3) I only have a 2-channel scope here so observing timings is a bit difficult.  I had tried adding in a few nop statements to line up the timings with Fig.28 in the data sheet.  (I'm using the same clock for both the micro and the AD2S1210)  The only difference functionally is I'm holding CS low instead of cycling it, but I think that should be fine?  Also are the timings in the the diagram minimum set up times or are those representative of maximums also that I can't violate?

    4) So when I say disconnected, I mean the micro is in a circuit by itself just to make sure it's actually outputting the correct signals.  The AD2S1210 is powered off at this point.

    Thanks for the reply.

  • +1
    •  Analog Employees 
    •  Super User 
    on Apr 13, 2021 6:36 PM in reply to nxg67djh356

    nxg,

    So if I understand your setup correctly RDB is driven high and you don't see the data (0x76h) you've applied to DB7-DB0 appear on the board when you probe correct?  Note I'm assuming you are using the customer evaluation kit here so please correct me if this is an incorrect assumption

    1) How are you forcing CS low?  have you tied it low using LK2 (position B) or some other method?

    2) Have you connected A1 and A0 to the J2/J4 connections so that you have software control by moving LK4 and LK5 to the C position?

    3) Can you verify that LK3 is connected to position B or C to ensure that RDb is driven high to avoid activating the output drivers

    4) LK703 is set in the A position to connect VDRIVE to DVDD or you have put this link in position B and provided a Voltage to connector J704 to your desired voltage.

    5) Please also make sure you can verify you have power to AVDD and DVDD.  Both should be 5V.   

    6) Lastly verify that RESET is not asserted (driven low).  There is an on-board POR that puts the device in RESET until the supply is in range.

    Sean

Reply
  • +1
    •  Analog Employees 
    •  Super User 
    on Apr 13, 2021 6:36 PM in reply to nxg67djh356

    nxg,

    So if I understand your setup correctly RDB is driven high and you don't see the data (0x76h) you've applied to DB7-DB0 appear on the board when you probe correct?  Note I'm assuming you are using the customer evaluation kit here so please correct me if this is an incorrect assumption

    1) How are you forcing CS low?  have you tied it low using LK2 (position B) or some other method?

    2) Have you connected A1 and A0 to the J2/J4 connections so that you have software control by moving LK4 and LK5 to the C position?

    3) Can you verify that LK3 is connected to position B or C to ensure that RDb is driven high to avoid activating the output drivers

    4) LK703 is set in the A position to connect VDRIVE to DVDD or you have put this link in position B and provided a Voltage to connector J704 to your desired voltage.

    5) Please also make sure you can verify you have power to AVDD and DVDD.  Both should be 5V.   

    6) Lastly verify that RESET is not asserted (driven low).  There is an on-board POR that puts the device in RESET until the supply is in range.

    Sean

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