How to switch on "weak pullups" for Cyclone in Quartus 10SP1

[Altera_Forum]

Hello, 

 I am doing a development using a Cylclone EP1C3T100. I am using Quartus 10 SP 1  My design needs a few DIP switches, and so I thought that I can use the internal pull-ups to get the high level. But I cannot configure them in Quartus.  1. Try: I use the Ressource Property Editor, I then select "Weak Pull Up" and set it to "ON". I then run "Edit"->"Check Ressource Properties" and it becomes accepted and printed bold. But when I then look into the synthesis result files, "Weak Pull Up" for the pin is OFF and also it is off if looking into the ressource properties afterwards.  2. Try: I generally switch weak pullups using "Assignments"->"Settings"->"Fitter Settings"->"More Settings..." and there at the very bottom is also a "Weak Pull Up" selection. If I turn on this, I get a fitter error: Error: Can't place I/O pin osc_clk at pin location 10 -- I/O pin uses weak pullup, which is not supported by this pin location  For methode# 2 I did not find how to turn off the weak pull up on Pin 10, all selections in the property editor are greyed out.  Any idea how to solve this? I would like to save the external pull up resistor.  Thanks a lot in advance, Günter (dl4mea)

[Altera_Forum]

--- Quote Start ---  Can't place I/O pin osc_clk at pin location 10 -- I/O pin uses weak pullup, which is not supported by this pin location  --- Quote End ---   Yes it's true. Pin10 is a dedicated clock input. Weak pull-up isn't supported for clock pins, only for general I/O pins.

[Altera_Forum]

Hello, 

 thanks for the confirmation. But how can I reach my goal of having the weak pullups active on the switch inputs?  Cheers, Günter

[Altera_Forum]

I didn't clearly understand from your post, if the reported problems have been with other pins than CLK0 (pin 10). With other pins, weak pull-up should work of course. But the resource property editor isn't the right way to do it, it's only intended for changes to a compiled design. You have to use either the assignment editor or the convenient pin planner. Columns showing the respective properties can be enabled in the pin planner.

[Altera_Forum]

--- Quote Start ---  can be enabled in the pin planner.  --- Quote End ---    Hello, thanks for the answer.  Even if it sounds foolish, can you please tell me the details steps how to enable a weak pullup in a EP1C3 device in pin planner? I had a look at all the options, but did not find the one that gives me this option. Some of the configurations in Quartus are really behind a labyrinth.  Thanks, Günter

[Altera_Forum]

As said, you have to enable the weak pull-up resistor column. It's done by the "Customize Columns" function in the context menu.

[Altera_Forum]

--- Quote Start ---  It's done by the "Customize Columns" function in the context menu.  --- Quote End ---    Hello FvM,  thanks a lot for your comment, now I got it. As I said, Quartus is a labyrinth of configuration options.  Thanks again, Günter