https://open-source-silicon.dev
Join Slack
Mmm, I think `write_cdl` is giving me a different netlist than `write_verilog` ...
# openroad
t
Mmm, I think 
write_cdl
is giving me a different netlist than 
write_verilog
...
m
@tnt what’s different?
t
Well, some of the top level ports are just plain just not connected in the CDL 😅
Compare say 
um_iw[10]
...
tt_mux.cdltt_mux.pnl.v
m
@tnt 
um_iw
is not connected in either netlist as far as I can see.
t
@Mitch Bailey huh ?
assign um_iw[10] = \block[0].zbuf_iw_I[10].z ;
Copy code
sg13g2_and2_2 \block[0].zbuf_iw_I[10].genblk1.cell0_I  (.A(\block[0].zbuf_iw_I[10].a ),
    .B(\block[0].l_ena_0_I.z ), 
    .X(\block[0].zbuf_iw_I[10].z ),
    .VDD(VPWR),
    .VSS(VGND));
Am I missing something here ?
m
@tnt Sorry, the browser window I was using didn’t hit any of the assigns on a search. Scrolling down to the bottom of the file there are definitely assign statements with 
um_iw
. Maybe 
write_cdl
doesn’t handle assigns.
t
The source is an openroad db and the connection in there is definitely good.
I'll try and read how 
write_cdl
works after I eat and see if I can see anything wrong in there ...
Definitely a bug. 
write_cdl
doesn't account at all for pins that are connected to nets with a different name ...
m
Calibre CDL allows a 
*.connect
statement to join nets. Don’t know if that’s standard spice or not. If LVS understands it, then that might be a solution.
t
I just modified it to use the pin name instead of the net name in those cases.
👍 1
12 Views
Open in Slack
PreviousNext
Powered by

What is Linen?

Linen is a search-engine friendly community platform. We offer integrations with existing Slack/Discord communities and make those conversations Google-searchable.

Powered by