Cyclone IV - Using high impedance in GPIO

[Altera_Forum]

I have a project with 14 bidir. I use to test integrated circuits from college.  

 i use the 36 gpio pins in a protoboard with a flat cable. but when i put the bidir in high impedance, all outputs go to high level (but they continue in high impedance).   Firstly i think the weak pull-up resistor is on (and turn off). After I tried turn off all programmable adjustments. Nothing worked.  I am a computer scientist and maybe my fail is in eletronic level. I don't know.  Any suggestions? What can you do to help me?

[Altera_Forum]

What is driving the wire when you put the FPGA pins in high impedance?

[Altera_Forum]

--- Quote Start ---  What is driving the wire when you put the FPGA pins in high impedance?  --- Quote End ---    The GPIO is connected to protoboard (flat cable). I didn't understand your question, but nothing is connected between pins and protoboard when are in high impedance.  https://www.alteraforum.com/forum/attachment.php?attachmentid=6918   FPGA >> PIN <> GPIO <> Protoboard

[Altera_Forum]

Since there isn't anything else driving the wire, when the bidir signals go into high-impedance state, the status present in the wire is "random".

[Altera_Forum]

--- Quote Start ---  Since there isn't anything else driving the wire, when the bidir signals go into high-impedance state, the status present in the wire is "random".  --- Quote End ---    So, why can I do?

[Altera_Forum]

--- Quote Start ---  So, why can I do?  --- Quote End ---    What's the problem?  If you need them low add very high value pull down resistors from each line to gnd.  ?  Nial

[Altera_Forum]

debugmaster, 

the question is: what behavior do you need?