I have completed the design flow of a MUX successf...
# sky130p
Preet Batavia
07/23/2021, 9:23 AMI have completed the design flow of a MUX successfully in openlane , i have various magic , spice files etc , i am not able to figure out how do i simulate it and visualize the inputs and outputs , please if someone could help me out here.
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Aastha Dave
07/23/2021, 11:35 AMyou could simulate it using ngspice outside the OpenLANE flow.
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Preet Batavia
07/23/2021, 12:37 PMyeah , openlane created a .spice file , but I am unable to simulate it on ngspice
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Aastha Dave
07/24/2021, 3:49 AMWhat error are you getting?
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Preet Batavia
07/24/2021, 4:25 AMthere is no error as such , but im lost as to how to get the waveforms on the GUI
Preet Batavia
07/24/2021, 4:26 AMthis is the netlist file created by openlane as .spice which is just changed to .txt for sending it.
Preet Batavia
07/24/2021, 5:04 AMIn this file what should I print / plot to get some output
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Aastha Dave
07/24/2021, 10:35 AMYou'll have to first invoke ngspice, then run plot commands.
"ngspice test1.spice"
"plot y vs time x" - plots output y with time sweeping input x values. You'll have to use appropriate variables according to your design
Aastha Dave
07/24/2021, 10:41 AMYou'll see the node names and voltage values listed after the invoke command. Pick out the output and input node names from there
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Preet Batavia
07/25/2021, 1:31 PMHey , on invoking "ngspice test1.spice", i am not getting any node names and voltage values
Preet Batavia
07/25/2021, 1:40 PMAlso , while running the design flow I got this :
Preet Batavia
07/25/2021, 1:41 PMbut i am getting that the design flow is successful
Preet Batavia
07/25/2021, 1:47 PMbut getting this too , so i suppose the power ports are not an issue , really sorry but im a novice at this
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Matt Venn
07/26/2021, 12:42 PMnot exactly what you want, but here's an example of how you can run a simulation with a spice file
Matt Venn
07/26/2021, 12:42 PMMatt Venn
07/26/2021, 12:43 PMthe spice file in this case is coming from extracting from a drawing made in magic instead of the output from openlane
Matt Venn
07/26/2021, 12:43 PMbut the concept is the same.
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Preet Batavia
07/26/2021, 1:33 PMthank you , ill try it out
Preet Batavia
07/26/2021, 5:56 PM@Matt Venn , i tried following your repo and it worked fine , i want to understand how did you write the pre.spice and post.spice so that i can also write it for my design to run a simulation
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Matt Venn
07/26/2021, 6:00 PMSpice is a bit of a pain to learn. I just copy and paste the same pieces. You might be better off learning pyspice python Library.
Matt Venn
07/26/2021, 6:01 PMIf you do want to learn, then the manual is not bad. Search for it and you should find it easily