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FMCOMMS2 Reference Design GPIO ports

Question asked by wmaguire on Jun 26, 2014
Latest reply on Feb 2, 2015 by

Hi all,


I have been porting the ADI FMCOMMS2 IP to a ZC706 target using Vivado 2014.2.  I have a few questions concerning the GPIO design for which I would welcome comment.  I ask as while I managed to get most of the project TCL to work, it left the GPIO section as 48 inputs, 48 tri state controls and 48 outputs, all unconnected.  


1.  Why are 48 GPIO wires defined when only 17 GPIO ports are needed?  I see no use of the remaining 31 wires in the system_top.v.

2. What are these used for ?

for (n = 0; n <= 14; n = n + 1) begin: g_iobuf_gpio_bd

  IOBUF i_iobuf_gpio_bd (

    .I (gpio_o[n]),

    .O (gpio_i[n]),

    .T (gpio_t[n]),

    .IO (gpio_bd[n]));



2.  Why are ports which are inputs and outputs only on the device defined as inout ports?  For example RESETB on the AD9361 chip is an input but the project sets it to inout?


Currently I am studying the Schematic for the board in conjunction with the associated XDC file to determine the FMC connections.  Is there a user manual and or datasheet document for the AD=FMCOMMS2-EBZ board?