hi <@U016EM8L91B> , two queries regarding LEF gene...
# magic
r
hi @Tim Edwards , two queries regarding LEF generation : 1. How are the shapes for the PINS determined in lef write command ? 2. I see although i have created the pin over met1 , VDD/VSS pins have RECT shapes for other layers as well Also any recommended settings for writing LEF file -- for using it on openlane of any higher flow ? Thanks.
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t
For a small layout like a standard cell, use
lef write
. For a large macro, use
lef write -hide
so that it just blocks the whole area (except the pins) with obstruction. The pins are determined by enumerating all shapes on a net and making all of them into shapes in the PIN record. There are various options to the
lef write
command for limiting the area marked as a pin. I expect what you want is just to do
lef write -hide
. Without
-hide
, all the internal nets will be in the abstract view; if the nets connect to a pin they will be part of the pin, and if not, they will be marked as obstruction layers.
r
@Tim Edwards A related query here is that in klayout i see there are PIN layers also. Ideally , if we create layers on the PIN layer , that only should be extracted in the LEF file - Is this understanding true ? This helps also to seperate the drawing layer and interface pin layer. But i dont see these PIN layers in magic . Am i missing anything here ?? Thanks
Also i write with -hide option and try to load back to klayout , but not able to , lef file is attached
lef.txt
t
Does klayout read LEF files? If so, is it giving you any relevant error message? The problem with the purpose might be that you need both the pin and drawing purposes; a pin purpose layer by itself is not legal layout.
r
This error message is being displayed. What i have noticed is that when there is a particular syntax issue (klayout related may be but not generic) , klayout throws this error.
image.png
Also trying to read in magic (correct command ??) % lef read decoder_with_pmos_D1_g5d10_tapped_2305.lef Reading LEF data from file decoder_with_pmos_D1_g5d10_tapped_2305.lef. This action cannot be undone. LEF read: Processed 93 lines. But no display on the layout window. Surely im not doing correct may be
t
In magic you need to follow that by
load <cellname>
, presumably here
load decoder_with_pmos_D1_g5d10_tapped_2305
.
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