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n

Nelson Rodriguez

02/11/2023, 2:53 PM
Morning everyone, one quick question, I'm trying to set the grid at 0.005um, but it remains at 0.01um. I was searching here and @Tim Edwards mentioned here to use
snap internal
but it didn't change it. Does anyone have any idea?
t

Tim Edwards

02/11/2023, 3:25 PM
Which technology file? Both sky130 and GF180MCU should have a minimum grid setting of 5nm. You should start magic with the
-rcfile
switch (e.g.,
magic -d XR -rcfile /path/to/sky130A.magicrc
), which runs (among other things important to the PDK setup) a grid scaling that scales from lambda (an initial grid scaling chosen somewhat arbitrarily) to the minimum manufacturing grid. If you're not using
-rcfile
(hint: you should), you can scale the grid down with the
scalegrid
command.
n

Nelson Rodriguez

02/20/2023, 10:08 PM
I was working with sky130. Thanks Tim, I'll start using the rcfile.
@Tim Edwards a little doubt. Once I open magic with the rc file and set
grid 0.005um 0.005um
, I still have to run
snap grid
because without it I can't work with the smallest dimensions. Now, let's say I type the above commands and also paint some lines using
source
command (because they are described in a tcl file) and save all of that. Once I want to open it again, nothing is saved, I have to type one more time the
snap grid
and source the tcl file with the lines again. Is there a solution to keep the effect of those commands in my previous work session?
t

Tim Edwards

02/21/2023, 2:36 PM
First: The
grid
command just draws grid lines. If you want to draw on the fine scale, just use
snap internal
(what you did is fine, too, just a bit more roundabout). If you are drawing geometry from the command line (or a script file), the
grid
and
snap
are irrelevant as long as you specify units (e.g.,
box 10um 10um 20um 20um;  paint m1
) "save all of that" followed by "nothing is saved" is contradictory. Can you provide an example of something you scripted? (A common misunderstanding is using the
save
command instead of the
writeall
command, which could be the issue here.)