Spartan IOB Input Switching Characteristic

[Michael]

Hi,

I have a fully routed Spartan3(Alliance 9,2) that I would like to keep
the routing and only change the "IOB Input Switching Characteristic" for
all used IOs, I know how to do this in the FPGA Editor but I would like
to do this using a new "ucf" file.

The reason is that I have some issues and like to try out different
Characteristics.

Anyone know how to do this?

/michael

 

[Ed McGettigan]

On Mar 28, 5:37 am, Michael <michael_laaja...@yahoo.com> wrote:

Hi,

I have a fully routed Spartan3(Alliance 9,2) that I would like to keep
the routing and only change the "IOB Input Switching Characteristic" for
all used IOs, I know how to do this in the FPGA Editor but I would like
to do this using a new "ucf" file.

The reason is that I have some issues and like to try out different
Characteristics.

Anyone know how to do this?

/michael

Going back the UCF file to make this change means that you need start
the design implementation over from the map and that could mean
changes in your placement and routing. The MAP and PAR tools do offer
the option to use a previous NCD file to guide the the mapping and
placement.

For both MAP and PAR this would be "-gf my_old.ncd -gm exact". The "-
gf" is the Guide File and the "-gm" is the Guide Mode.

Using FPGA Editor will be far easier to accomplish what you want to do
and you don't need to do everything through the GUI. Use the GUI the
first time to get the commands to select an IOB and change the
IOSTANDARD and then create a text file to replicate these commands
across all of your IOBs. You can run this script using the non-GUI
version by using the fpga_edline tool instead of fpga_editor.

fpga_edline -p my_script.txt my_design.ncd

Don't forget to add a save command to write the NCD at the end before
quitting.

Ed McGettigan
--
Xilinx Inc.

 

[Michael]

Hi,

On 03/28/11 04:37 PM, Ed McGettigan wrote:

On Mar 28, 5:37 am, Michael<michael_laaja...@yahoo.com> wrote:
Hi,

I have a fully routed Spartan3(Alliance 9,2) that I would like to keep
the routing and only change the "IOB Input Switching Characteristic" for
all used IOs, I know how to do this in the FPGA Editor but I would like
to do this using a new "ucf" file.

The reason is that I have some issues and like to try out different
Characteristics.

Anyone know how to do this?

/michael

Going back the UCF file to make this change means that you need start
the design implementation over from the map and that could mean
changes in your placement and routing. The MAP and PAR tools do offer
the option to use a previous NCD file to guide the the mapping and
placement.
No I don't like to do like that.

For both MAP and PAR this would be "-gf my_old.ncd -gm exact". The "-
gf" is the Guide File and the "-gm" is the Guide Mode.

Using FPGA Editor will be far easier to accomplish what you want to do
and you don't need to do everything through the GUI. Use the GUI the
first time to get the commands to select an IOB and change the
IOSTANDARD and then create a text file to replicate these commands
across all of your IOBs. You can run this script using the non-GUI
version by using the fpga_edline tool instead of fpga_editor.

fpga_edline -p my_script.txt my_design.ncd

Don't forget to add a save command to write the NCD at the end before
quitting.

Ed McGettigan
--
Xilinx Inc.


Ok, that sounds like the best way thanks!!

/michael