Answers Database
M1.5: EPIC: How to read the equation inside of a LUT in FPGAs
Record #4348
Product Family: Software
Product Line: FPGA Implementation
Product Part: Epic
Problem Title:
M1.5: EPIC: How to read the equation inside of a LUT in FPGAs
Problem Description:
Urgency:
Standard
General Description:
Customers sometimes wonder how the logic was synthesized into Look
Up Tables in FPGAs.
Solution 1:
Equations are generated in the form of report files for CPLDs (such as
XC9500 family) only . For FPGAs, where the Combinational logic is
implemented as LUT (look up table) , you can look up what is in a LUT
in EPIC design editor (lowest button on the right side in Design Manager
GUI). Alternatively, you can run 'ncdread' in command line (Dos
prompt) on the map.ncd file or design.ncd file.
To look at the equation in EPIC Design Editor:
1. In EPIC Design Editor, select the CLB of your choice. The color
of the CLB will change to red.
2. Click 'editblock' button on the right. It will bring you to the logic
block editor.
3. Click on 'Attr' button in Logic Block Editor. That will bring up the
'logic equations' window.
4. You can edit the equation there if you like.
To run 'ncdread' in command line, do the followings:
1. Open a dos prompt.
2. Go to project director\xproj\<ver>\<rev> directory.
3. Run
Ncdread -o <output_dump_file> map.ncd
4. Open the <output_dump_file> with any text editor.
(Note: In order to be able to run the command line, you may need to
type: set path= %xilinx%\bin\nt and enter at the command prompt
before step 3.
For more information, please refer to Libraries Guides from the
dynatext browser. (Click on Start-> Programs -> Xilinx
Foundations Series -> Online Books to invoke the dynatext browser
End of Record #4348 - Last Modified: 05/25/99 10:09 |
