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Len, if you want it for SwCAD, I can show you how to set up the Schmitt trigger that's in the digital library to do a fair emulation of a 74LS14. Or you might figure it out for yourself.ljcox said:Does anyone know where I can find one? I've tried the Fairchild and Texas Inst sites but to no avail.
Thanks
OK, place a Schmitt trigger on the schematic and right-click on it. Below is a screen capture of this. I parameterized the logic high voltage as an example. You could just make it 4, or 5, or whatever you think is right. I also picked typical values for delay, rise time, threshold voltage, and hysteresis. You can get them from the datasheet. If you want to add input and output resistance and capacitance, you will have to add them externally.ljcox said:Ron,
I looked at it but could not see how to do it. So please advise.
Len, I hope I didn't leave the impression that I'm reluctant to help. I guess I get my strokes this way. :lol:ljcox said:Thanks Ron, much appreciated.
I'll hopefully be able to do it myself in the future.
I should move to Oz this time of year. The temperature got all the way up to -2C today here in Boise. Garden, indeed! :xljcox said:No Ron, I did not mean to imply that. I meant that I want to be able to learn how to write the models myself so, eventually, I don't need to ask.
But I expect I'll need more tuition yet.
I have not looked at the model yet, the garden & gardener (wife) await my attention.
ljcox said:Ron,
In Melbourne, we don't have -2C even in winter. When I extracted myself from the garden, I fooled with SwCAD. Two questions:-
1. I inserted your model, but I can't see how to specify Vcc - see the screen dump below.
This is also done using .op. Type in "K1 L1 L2 0.999" (or whatever value you choose) and click OK.2. I read the help about mutual inductance, it said to use this format:- K1 L1 L2 1 but can't see how to input this data. I assume that L1 and L2 are drawn in the normal way and then the Mutual Inductance parameters are input to connect them.
Please help.
Edit: I tried to upload the attachment twice but an upload error occurred both times.
What happened was that when I tried to run the simulation, an error message said essentially: Don't recognise Vcc. I had wondered about specifying Vcc, but could not see how to do it.
No problema, de nada, etc., etc. :lol:ljcox said:Thanks Ron
OK, place a Schmitt trigger on the schematic and right-click on it. Below is a screen capture of this. I parameterized the logic high voltage as an example. You could just make it 4, or 5, or whatever you think is right. I also picked typical values for delay, rise time, threshold voltage, and hysteresis. You can get them from the datasheet. If you want to add input and output resistance and capacitance, you will have to add them externally.
This model is only behavioral, but is still very useful, and runs very fast.
You can, of course, do similar setups with any of the digital parts. The D FF is very useful. I made a model of a 4-bit counter using these models,and it matched the CMOS part (can't remember which one, and I think it's on my computer at work) pretty well.