Can I set a weak pull up resistor on an output port ?

Question

Hi,
The PFL we are using has a pull-up resistor 10K on the fpga_nconfig line (output from PFL within CPLD MAXV &amp; input to the FPGA) but currently have issues of the fpga-nconfig line driven low somehow (cannot figure out).
I've seen on the internet comments from people saying the a weak pull up can be set only on input or bidirectional ports. Is this the case ?
Because when I set this manually within the .qsf for the output port fpga_nconfig :
         set_instance_assignment -name WEAK_PULL_UP_RESISTOR ON -to fpga_nconfig

&amp; later looked at the Assignment Editor, noticed that it accepted it as a weak pull up. But it replaced the:

'Assignment Name' from : Location -&gt;  Weak Pull-Up resistor
'Value' from: PIN_E5 -&gt; On

Did not attempt to run this yet.  
Where is eg the PIN_E5 pin location assignment gone for the fpga_nconfig pin? It's been now replaced by a Weak Pull-Up resistor and removed the PIN_E5 location assignment.
Please comment here !

Regards,
Kevin

knug · Answer

Replying to myself here. Resolved part of my query..
Ok, within the Assignment editor can also see further down the list the location assignment PIN_E5 for fpga_nconfig.  So I could see that the 2 following location assignments I defined within my .qsf were both listed within the Assignmenr Editor window  
set_location_assignment PIN_E5 -to fpga_nconfig
set_instance_assignment -name WEAK_PULL_UP_RESISTOR ON -to fpga_nconfig

Q/  BUT is is ok to set a WEAK_PULL_UP_RESISTOR on an output port ?
If this is not ok, I must go and set this up from the FPGA side which is declared as an input port.
But it will not resolve the problem I am trying to resolve at the moment ie to why nconfig is pulled low after programming/configuring the loadware PFL code before even autodetecting the flash to program it with the main application code that later on should configure the FPGA

knug · Answer

Can someone please answer my following question before end of the day, so I can attempt to try it out to see if it resolves my problem ?
Q / Is is ok to set a WEAK_PULL_UP_RESISTOR on an output port ?
&amp; can I set a WEAK_PULL_UP_RESISTOR on a port that has already an external pull-up resistor of 10K ?

knug · Answer

Tried the weak pull up resistor BUT it did not resolve the issue I had !

nuraiman_m_intel · Answer

Hi Kevin,Thank you for contacting Intel community.Apologize for the delay in response as I just received this case today.Per my understanding from MAX V pin connection guidelines, connect this TMS and TDI input pins to a 10-kΩ pull-up resistor to VCCIO1. https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/dp/max-v/pcg-01012.pdfThe Weak Pull-Up Resistor option should not be used at the same time as the Enable Bus-Hold Circuitry option. This option must be assigned to a pin or it is ignored.Let me know if this is not the answer you are looking for as what I understand is you wanted to know if weal pull up resistor can be set to output port or not.Regards,Aiman

nuraiman_m_intel · Answer

We do not receive any response from you to the previous answer that I have provided. This thread will be transitioned to community support. If you have a new question, feel free to open a new thread to get the support from Intel experts. Otherwise, the community users will continue to help you on this thread. Thank you.

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Can I set a weak pull up resistor on an output port ?

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