[alvin]

Assuming I have defined cellA and it has the pin ‘lb’ which is set to be at the bottom left corner of the cell. I want to put a space in y-direction of 50 um between cellA and the sequent cell (cellB) automatically without knowing the actual size of cellA.
I found if I do this:

nd.cp.goto_pin(cellA.pin['lb'])
nd.cp.move(0,-50,0)
cellB.put()

It returns an error:

Exception: Not allowed to create a node outside the scope of max one level deep.

associated with the use of

nd.cp.move(0,-50,0)

after using

nd.cp.goto_pin

However, there is no error if I do this:

nd.cp.goto_pin(cellA.pin['lb'])
xya = nd.cp.here()
nd.cp.goto(xya.x,xya.y)
nd.cp.move(0,-50,0)
cellB.put()

It is a little bit troublesome!! Is there any way I can use

nd.cp.move(0,-50,0)

right away?

[alvin]

Thanks Ronald. This has been very helpful. I have been building my own PDK like the follows.

sifab = nd.add_xsection(name='sifab')
sifab.os = 0.0
nd.add_layer2xsection(xsection='sifab', layer=1, accuracy=0.0001)
nd.add_layer2xsection(xsection='sifab', layer=2, accuracy=0.0010, growx=10)
wg = nd.interconnects.Interconnect(width=0.5, radius=20, xs='sifab')

If later on, I want to recall the value of ‘growx’ in layer 2 of ‘sifab’, how can I do that?

[alvin]

Many thanks to Xaveer and Ronald. In fact, where can I see all the attributes (e.g. width, radius, os, cladding width, etc) corresponding to an existing PDK?

I know I can do the followings to see all the PDK in demofab:

import nazca as nd
import nazca.demofab as demo

nd.show_xsections()

As what Xaveer said, it would be convenient to use an existing PDK as template and implement my own technology. But, how to actually do that? Can I “import” demofab.shallow to a new xsection and start to do modification from that?

Maybe there is specific section for this in the manual. Please refer me to that.

[alvin]

Can I do subtraction based on the whole layer so as to reverse the tone of the mask? Alternatively, is there any method written in the library to simply produce positive mask?

[Author]

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