Hello, I am new in using Kicad, and i tried to simulate a 7408 logic gate, I took the Pspice model from Orcad Cis Lite for it and put in the project file. The circuit is like in image below and the model aswell.
When i try to simulate this with a transient .1 1 the simulator stop working and a restart of the program is required. I don’t know what’s the problem here but I wait for your response. Thanks!
Anyway you can ZIP up your KiCad project (including the Pspice model library) and upload it somewhere so I can download it and take a look?
Sure, here it’s the link.
Cool. Thanks.
I don’t get a crash, but I can see several problems mainly due with assuming you can implant this 7400.lib from OrCAD into a generic SPICE program. If you analyze the .lib file, there seems to be many things which are relying on the OrCAD GUI to provide additional information. First, are the power rails which OrCAD seems to handle “behind the scenes” with some global power flags called $G_DPWR and $G_DGND. Second, much of the ICs described here call other generic subcircuits such as and(x), buf3, and inva(x) which are not defined in this .lib file. It’s likely OrCAD is including another .lib file in addition to this one to supply these generic functions.
Basically, it’s going to take additional work to successfully convert these logic libraries to be used in a generic SPICE problem. So it depends what you need to accomplish. If you just need to implement a trivial AND function, there are more simpler and universal ways to accomplish that.
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Honestly, I need to implement this circuit for my paper license. I tried to use Orcad but the lite version dosen’t let me to use more than 60 components, so i looking for other program to implement this circuit.
So you need 7404, 7408, 7414, and 7474? Does it need to be specifically be the original TTL versions? For example, does it need to be 7404 exactly, or is 74LS04 or 74HC04 or 74LVC04 families OK? Or can it just be a generic inverter function not specific to any logic family?
I think that I could use other families like you metinonate. My teacher said that to implement the circuit in Simulink so there are not the specific 7408 or something like that, there is XOR, OR, AND Flip-flop etc. So again i think i could use anything…
Why don’t you just use Simulink, then? (Or Xcos if there’s a licensing problem)
It’s more complicate to use than Orcad or other program. Just look how it’s looks like a basic circuit and i don’t even make it works. He dosen’t let you to make simple connection between resistors, capactiors / D flip-flop.
If that’s the case, I think you’re better off using LTspice for this. It has built-in digital functions which can be configured quite easily. You just need to study the Help section for the “A-devices” and also doesn’t hurt to look at Documents\LTspiceXVII\examples\Educational\160.asc to get an idea of how to use them. This is not an LTspice forum so if you need specific help beyond that you will have to look elsewhere.
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Thank you! So, in Kicad i can’t implement that circuit?
You can, but it’s much more complicated to achieve since you have to find or create models for all the components.
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