palaniappan-r's picture
Add markdown sources
d59bb1b verified

How to generate a SPEF (write_spef) including coordinate information?

Tool: Parasitics Extraction

Subcategory: SPEF format

Conversation

xlindo

As the default flow, there is no coordinate information in *CONN following each PORT in the generated 6_final.spef, which is not in coincidence with a normal SPEF format.

E.g., no *C bolow,

image

...

*CONN
*I *572:B I *D sky130_fd_sc_hd__nand2_1
*I *571:Y O *D sky130_fd_sc_hd__nand2_1

...

Compared with another example in a book,

*D_NET *5423 2.69358 

*CONN 
*I *14207:D I *C 21.7450 94.3150 
*I *14205:D I *C 21.7450 90.4900 
*I *14211:Q O *C 21.4900 83.8800 *D DFFQX1 

*CAP 
1 *5423:10107 *547:12722 0.202686 
2 *5423:10107 *5116:10594 0.104195

....

Any boss help me?

maliberty

Coordinates are optional in spef so this is valid. There is code to generate coordinates but we've never used it. We could try enabling but I can't make any guarantees about what it will produce. Do you have a use model for these or are you just comparing to what a book shows?

maliberty

I've added a -coordinates option to write_spef in https://github.com/The-OpenROAD-Project/OpenROAD/pull/3434