DC potential problem

[Mahesh Shinde]

I am working on MazeRouter synthesize. I have synthesized my code but I am getting 16 potential problems. Somethg like this
Warning: In design 'maze_router', cell 'C48640' does not drive any nets. (LINT-1)
Warning: In design 'maze_router', cell 'C48791' does not drive any nets. (LINT-1)
Warning: In design 'maze_router', cell 'C48792' does not drive any nets. (LINT-1)
Warning: In design 'maze_router', cell 'C48793' does not drive any nets. (LINT-1)
Warning: In design 'maze_router', cell 'C49437' does not drive any nets. (LINT-1)
Warning: In design 'maze_router', cell 'C49602' does not drive any nets. (LINT-1)
Warning: In design 'maze_router', cell 'C49735' does not drive any nets. (LINT-1)
Warning: In design 'maze_router', cell 'C49744' does not drive any nets. (LINT-1)
Warning: In design 'maze_router', cell 'C49780' does not drive any nets. (LINT-1)
Warning: In design 'maze_router', cell 'C49825' does not drive any nets. (LINT-1)
Warning: In design 'maze_router', cell 'C49873' does not drive any nets. (LINT-1)
Warning: In design 'maze_router', cell 'C50075' does not drive any nets. (LINT-1)
Warning: In design 'maze_router', cell 'I_726' does not drive any nets. (LINT-1)
Warning: In design 'maze_router', cell 'C50220' does not drive any nets. (LINT-1)
Warning: In design 'maze_router', cell 'C50221' does not drive any nets. (LINT-1)
Warning: In design 'maze_router', cell 'C50228' does not drive any nets. (LINT-1)
Warning: In design 'maze_router', cell 'C50488' does not drive any nets. (LINT-1)
Warning: In design 'maze_router', cell 'C50493' does not drive any nets. (LINT-1)
Warning: In design 'maze_router', cell 'C50496' does not drive any nets. (LINT-1)
Warning: In design 'maze_router', cell 'C50499' does not drive any nets. (LINT-1)
1

I dont know how to solve this ?
When I do post-synthesis simulation using the netlist generated from above design, I am getting wrong output results. I think its because of this only. Please help me with this. Thanks in advance

 

[vcnvcc]

This is not solution to your question - But some pointers which you need to check

1. Check in generated netlist - the output of the cell is connected to somewhere or just left open?
(I think it would not be connected to anywhere - as indicated by mentioned warning.)
2. check the library from where to these cells are picked up - Is there any discrepancy?
3. Is there are any other similar cells, which are connected from same library?

 

[Mahesh Shinde]

I made some changes in code and now I am getting output but I am getting warnings in sdf file.

Attempt to annotate a negative value to a 1 limit timing check in instance (tb.my_maze_router.i_reg_0_), setting to 0<../syn/sdf/maze_router.sdf, line150198>.

what should I do to remove these warnings? I getting expected result.

 

[vcnvcc]

I made some changes in code and now I am getting output but I am getting warnings in sdf file.

Attempt to annotate a negative value to a 1 limit timing check in instance (tb.my_maze_router.i_reg_0_), setting to 0<../syn/sdf/maze_router.sdf, line150198>.

what should I do to remove these warnings? I getting expected result.

I have a question - related to SDF file in Synthesis
How sdf file is generated? Is it generated by DC? what I know is after PnR - we get spef & using PT we dump SDFfiles..

But you are using SDF during synthesis... Can you or Anyone explain it??

 

[Mahesh Shinde]

sdf file is generated during synthesis itself by design compiler. You just provide the design and run the script to synthesize it.