Implementation

[nickagian]

I have created a command line batch file to setup my ISE project and I would like to set this property to "For Outputs Only". What is the correct way to do this? Right now I have added the

project set "Pack I/O Registers/Latches into IOBs" "For Outputs Only" -process "Map"

entry to my .tcl file that I then call with the xtclsh command. However when I then open the ISE project that is created the option is always set to its default value ("Off"). Do I do sth wrong?

Thanx a lot!

[rcingham]

What version of ISE tools?

[nickagian]

I use

Release Version: 13.4 (nt64)

Application Version: O.87xd

[ambrosef]

The syntax appears correct, I performed a quick check of this in 14.1 and it appears this property is not being set when I rebuild the project aswell.

My tcl file uses:

   project set "Pack I/O Registers/Latches into IOBs" "For Outputs Only" -process "Map"

I did try some other properties to see if they were updated, e.g.

   project set "Starting Placer Cost Table (1-100)" "2" -process "Map"

This was applied correctly. There appears to be a problem with the "Pack I/O Registers/Latches into IOBs" property getting applied to the project correctly via the Tcl.

I cannot find any existing CR/bugs on this in our database and will file one. To workaround this you will need to manually set this I'm afraid.

[pedro_uno]

Can anyone answer this same question for Vivado?  I don't see any way to set this option in Vivado.

[bwade]

ISE supports two mechanisms for packing registers into IOBs. There is IOB=TRUE|FALSE|FORCE and also the map command switch -pr i|o|b which enables input|output|both packs for eligible registers, it is off by default. The -pr switch has no effect on registers that have IOB properties since the constraint takes precedence over the command line switch. 

Vivado supports the IOB property but only TRUE|FALSE. The TRUE behavior is equivalent to the  ISE's FORCE behavior in that the tool errors out if the IOB pack is not possible. Vivado has no feature equivalent to ISEs -pr option. If a register is eligible for both input and output packs, the behavior can be controlled with other constraints such as LOC constraints to the ILOGIC/OLOGIC site involved.