[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [oc] FPGA- Constrains



Hi,
 
look on the xilinx website at the Constraints Guide
 
http://toolbox.xilinx.com/docsan/xilinx5/manuals.htm
 
This will explain how to put TIG (timing ignore) constraints in your UCF file which wil help the P&R tools ignore false or not interesting paths in the design.
/MikeJ
----- Original Message -----
Sent: Saturday, October 19, 2002 11:25 AM
Subject: [oc] FPGA- Constrains

Hi All,

I mailed earlier to the cores list about my problem and asked for help but unfortunately got no replies. So I am trying to put my question in a little different way:::  

Firstly, I would like to introduce myself. I completed my Masters in Engg( spl in Digital Systems) from Osmaina University, Hyderabad, India very recently and joined a pvt firm as a trainee.

I am working on FPGA-Validation of a fairly large design, before it goes for the fab. My job is to port the design onto FPGA (VirtexE device of Xilinx) for this purpose. The problem I am facing is that the frequency of operation that I am able to achieve is very less, and the design being large, I cannot change my design for the FPGA. I need to put Constraints thru UCF and make it run at as high a frequency as the tool can give me. I am working with FPGA express for synthesis and ISE 4.1i for PNR. 

I am trying to port the Synopsys's DC directives like " set_false_path", "set multicycle_path", set dont_touch" and any other  attributes that would help me in reducing the critical path delay in my design. [and constrain the net delay, ofcourse]

Can any one of you kindly point me to some relavant documentation on approach to applying constraints on a design, in general and similar documentation on FPGA constraints?

Please correct me if my approach is wrong. Please let me know if I am not clear in any aspect.

Thank you.

Rayaprolu

 



Do you Yahoo!?
Y! Web Hosting - Let the expert host your web site