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Cal-linux
Visitor
Visitor
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Registered: ‎04-07-2020

Conflicting or incomplete information in Docs

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Hi,

While working on a board design with the Zynq XCZ014S-CLG400, I find the following conflicting or missing/incomplete information:

  • RSVDGND pins:  UG585 (Zynq-7000 TRM) instructs to tie to ground (Table 2-13, page 59).  UG865 (Zynq-7000 Packaging and Pinout) indicates:  "Reserved pins — do not connect"  (Table 1-5, page 13).

    Question:  which one is correct?
  • VCCBATT_0:  UG865, Table 1-5 states "this pin should be tied to the appropriate VCC or GND when not used" .... 

    Question:  How should I read that?  Is it that if not used, then connect to either VCC or GND?  Or is it:  connect to VCC if used, otherwise connect to GND?

    Additional question:  Would it be ok if I leave VCCBATT unconnected?
  • VREFP, VREFN:  UG585 (TRM) indicates "Reference input (1.25V) and ground".   UG865 seems to say the same, but in a very confusing way:  it describes VREFN as "1.25V reference GND reference" ....  ( ????? ).

    Question:  if I'm not using the ADC, do I still need to connect these?   Can I leave them floating or connect them to GND?

Thanks,
Cal-linux
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iguo
Xilinx Employee
Xilinx Employee
524 Views
Registered: ‎08-10-2008

1. RESVDGND: connect it to GND.

2. If you don't use VCCBATT, you can connect it either to VCC or to GND, nothing different here. Better not leave it floating.

3. VREFP is connected to 1.25V and Vrefn is connected to GND when you use external reference. If you don't use XADC, connect both to GND. You can refer to UG580 for more details on this.

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2 Replies
iguo
Xilinx Employee
Xilinx Employee
525 Views
Registered: ‎08-10-2008

1. RESVDGND: connect it to GND.

2. If you don't use VCCBATT, you can connect it either to VCC or to GND, nothing different here. Better not leave it floating.

3. VREFP is connected to 1.25V and Vrefn is connected to GND when you use external reference. If you don't use XADC, connect both to GND. You can refer to UG580 for more details on this.

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Cal-linux
Visitor
Visitor
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Registered: ‎04-07-2020
Thanks iguo,
I guess you meant to say UG480 (and not 580). In any case, UG480 does clearly show the details, including the instructions to connect VCCADC to VCCAUX if the ADC is not used, and never to ground.

Cheers,
Cal-linux
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