https://open-source-silicon.dev logo
#openlane
Title
# openlane
o

Olof Kindgren

12/28/2021, 7:09 PM
From grepping in the build results it looks like it's a
sky130_fd_sc_hd__buf_1
but at what point are these numeric identifiers created, and from what?
l

Lofty

12/28/2021, 7:21 PM
Somebody needs to add
autoname
to the openlane Yosys script...
It's Yosys creating those names
m

Matt Venn

12/28/2021, 7:26 PM
The numbers at the end are drive strength or number of inputs
In this case drive I think
l

Lofty

12/28/2021, 7:28 PM
I interpreted this as meaning things like
_20535_
and
_20164_
from Olof's previous message
m

Matt Venn

12/28/2021, 7:28 PM
Those look like wire names
l

Lofty

12/28/2021, 7:28 PM
Created by Yosys.
m

Matt Venn

12/28/2021, 7:29 PM
Autoname sounds useful
l

Lofty

12/28/2021, 7:30 PM
The names it generates are..less than useful, but, still a bit better than the numeric wire names Yosys normally creates
o

Olof Kindgren

12/28/2021, 9:32 PM
I traced them to be the clock signals. Is that yosys adding clock buffers or the CTS stage? From the clock input net to the point of failure I counted one sky130_fd_sc_hd__clkbuf_16 followed by three sky130_fd_sc_hd__clkbuf_2 in a row, three additional sky130_fd_sc_hd__clkbuf_16, one sky130_fd_sc_hd__inv_2 and finally one sky130_fd_sc_hd__buf_1
In total, roughly one gazillion buffers
l

Lofty

12/28/2021, 9:33 PM
CTS inserts clock buffers
o

Olof Kindgren

12/28/2021, 9:33 PM
Then I guess yosys autoname wouldn't help here?