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Hi, I edited a LEF file using Klayout using the sky130A technology and saved it as a GDS. When I ope...
# klayout
h
Hi, I edited a LEF file using Klayout using the sky130A technology and saved it as a GDS. When I open the saved GDS file, the layers are named 
1/0
, 
1/1
and so on rather than the sky130A names. Loading the layout using the same sky130A technology fails to load the layer properties correct. This does not happen when saved as an OASIS file or MAG layout. Is there some configuration I need to set to correctly save the layout? Thanks.
a
It sounds like you don't have a layer mapping on your tech file. You would need to go into the LEF settings for the technology and create a layermap. Are you using a tech file from open PDKs? There should already be a layer mapping.
h
Yes I am using the layermap from open PDKs. The layers appear fine while editing, and also while opening the oas file.
I'll send the files here in some time
vref_gen_nmos_with_trim_new.lef,vref_gen_nmos_with_trim_new.gds,vref_gen_nmos_with_trim_new.mag,vref_gen_nmos_with_trim_new.oas
vref_gen_nmos_with_trim.lefvref_gen_nmos_with_trim_new.lefvref_gen_nmos_with_trim_new.magvref_gen_nmos_with_trim_new.gdsvref_gen_nmos_with_trim_new.oas
The 
.lef
file is the original, the other files were saved by editing the original. When loading the saved 
.gds
file, layer information is not loaded (first image), whereas it is retained in the other files (
.oas
and 
.mag
, second image).
a
There are a few issues going on here. GDS does not store names of the layers, only OAS does. This is why GDS has to be used in combination with a layerprop file to display the layer names when using the GUI. Your tech file should point to a layerprop file. Make sure you have the tech file loaded before opening up the GDS. Second, the layer numbers (X/Y) do not look correct. KLayout will increase the number 1 by 1 when it doesn't have a layer map to use when it loads the LEF. You can look at the KLayout tech and see the mappings in there. Or go on the skywater readthedocs and see the layer numbers there. You need to load the technology before loading the LEF.
h
> There are a few issues going on here. GDS does not store names of the layers, only OAS does. This is why GDS has to be used in combination with a layerprop file to display the layer names when using the GUI. Your tech file should point to a layerprop file. Make sure you have the tech file loaded before opening up the GDS. > Yes the lyp file is loaded along with the technology file. > Second, the layer numbers (X/Y) do not look correct. KLayout will increase the number 1 by 1 when it doesn't have a layer map to use when it loads the LEF. You can look at the KLayout tech and see the mappings in there. Or go on the skywater readthedocs and see the layer numbers there. You need to load the technology before loading the LEF. > I did load the technology while loading the lef.
Does the lef reader require a different layerprop file?
Unless I am importing the tech file incorrectly?
I am using the `libs.tech/klayout/tech/sky130A.lyt`file from open pdks
a
Open up the tech file settings and make sure that the LEF layer to GDS layer settings are populated
h
In the lef reader settings? I believe they are.
It seems the open_pdks klayout tech was missing a 
.map
file. I got the file using Volare and it seems to work now, thanks!
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