Setting termination for I/O pads

[Altera_Forum]

Hi all,  

I have problem setting the termination for IOs. It complained that The current strength setting is not allowed together with termination setting. But I can't remove the current strength. How to work around this?  Thanks alot Jeff

[Altera_Forum]

--- Quote Start ---  But I can't remove the current strength.  --- Quote End ---  Why? Series termination and current strength are different ways to specify the same thing: Selecting one or several output transistors of different area for the IO driver.

[Altera_Forum]

Hi FvM, thanks for the response.  

The current strength is just there in the pin assignment. :|. Either 2mA(default) or max or min ... But any option will cause the conflict with the series termination.  Thanks :) Jeff

[Altera_Forum]

I have a similar issue: I wanted to use the current strength option -max but it conflicted with a termination setting, where: the was no such setting. I just specified 2,5 for IO. 

 How does this come?:confused:

[Altera_Forum]

Spent a day debugging a similar issue Quartus 9.1SP2. I would like to share this info because it was day wasted debugging what appears to be a defect in Quartus. The Quartus's makes a fale error message after set a IO pin current strength. As above user noted, I too was able to compile the design using series termination, but got errors if I switched to current strength/slew rate setting. I also realize series termination and current strength eventually boils into the same thing, but I was annoyed that Quartus was giving me what appears to be a BS error messages. 

 "Error: Current Strength logic option is set to 12mA for pin XXX, but setting is not allowed with a Termination assignment"  This error message is not valid because I removed the termination assignment setting and checked the QSF, restarted Quartus, and it still generated this error. Since I knew this setting was valid for my device, I sifted through different QSF settings line by line and doing a recompile for every possible setting, eventually I get to the point where if a turn off incremental recompile the error goes away. So turning off incremental recompile seems to fix it. Maybe guru's know this trick, but it was not obvious thing to do. It seems like a bug in incremental recompile.

[Altera_Forum]

--- Quote Start ---  It seems like a bug in incremental recompile.  --- Quote End ---   Yes, apparently. You should report to Altera support. Besides disabling the incremental compilation, also deleting the db directory would remove all invisible traces of previous I/O settings.