Hello @Matt Venn @Tim Edwards , I got a warning/error(multiple conflicting drivers) when i tried to synthesize this verilog code in open lane .But i did not get any error when i synthesized using yosys because multiple conflicting drivers issue was resolved in yosys. I am attaching errors to this message . Thank you.

@Aadhithya koramoni Are you saying that you synthesized the verilog in yosys outside of openlane and did not get an error? If you did, is the version of yosys that you used outside of openlane the same as the version of yosys that openlane uses? Looking at you verilog code, it appears that

BR_EN

is being driven in 2 blocks on the posedge of

CLK

. The block starting at line 80 and the block starting at 211. This one of the errors.

@Mitch Bailey Thank you for the reply. These warnings were present in Yosys but synthesis was successful. Whereas OpenLane threw an error when i tried to do synthesis. Is it okay to ignore warnings and proceed to PnR stage? I am asking this question because we can ignore warnings but not errors.

I think your report

1-synthesis_pre_synth.chk.rpt

shows at least 2 errors in addition to all the warnings. The errors are what is stopping openlane. You might be able to proceed to PnR, but your design might not work because you have multiple drivers for the same net. (It is conceivable that if the inputs to the drivers were always the same logical level, that there might not be a problem.)

@Mitch Bailey The file 1-synthesis_pre_synth.chk.rpt has only warnings. Although these were resolved by yosys, OpenLane threw errors. I am attaching screenshots for better understanding of the problem.

Ok. Like @Kareem Farid says, this can be dangerous - your design may not work as you intended. If you want to continue with place and route, add this to your config file.

"QUIT_ON_SYTHN_CHECKS": 0,

I had the same problems running openlane in Google Colab, so I change the Yosys Version from 0.38 to 0.34 and it managed to go from step 1 to step 27(Checking Wire Lengths) where it crashed. The "...has no driver" and "ABC: Error: The network is combinational" remained. I got an older version of openlane in my pc and the flow of the exact same design finished successfully.

@Diana Natali Maldonado Ramirez Thank you for the reply. So you ignored the error in the older version of openlane and proceeded to PnR stage ?