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Stream Operator
Joined: Oct 13, 2007 Posts: 6221 Location: near Austin, Tx, USA
Audio files: 267
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Posted: Wed Jun 27, 2012 4:29 pm Post subject:
Spice 3f5 Lunetta Simulations Subject description: Transistor Level Sims! |
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At JovianPyx's suggestion I started looking into simulators. It seems that our best simulator for Lunettas is Spice 3f5, available cross-platform and as MacSpice for my Mac. I've started working on a library file and have created some test files and captured one early plot. It's beginning to shape up nicely.
If this keeps up, we will soon have the capability to do mixed signal simulations of practical Lunetta circuits, and be able to share files with each other despite our community's use of three different operating systems. I love the idea of not having to wire up anything to simulate a Lunetta, and also the ability to explore circuits that I don't have the chips for at the moment without having to wait for a parts order is nice.
Anyway, for all the reasons that simulators rock, here we have the beginnings of our own library file!
Les
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4064 Time(s) |
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the em library file for 4000 series cmos, with a few basic models already! |
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CD4000em.lib |
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2.68 KB |
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296 Time(s) |
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Generic_test.cir |
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487 Bytes |
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_________________ "Let's make noise for peace." - Kijjaz Last edited by Inventor on Wed Jun 27, 2012 10:25 pm; edited 1 time in total |
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Inventor
Stream Operator
Joined: Oct 13, 2007 Posts: 6221 Location: near Austin, Tx, USA
Audio files: 267
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Posted: Wed Jun 27, 2012 4:31 pm Post subject:
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Some more circuit files for simulation...
Les
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CD40106_test.cir |
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424 Bytes |
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CD4013_test.cir |
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560 Bytes |
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169 Time(s) |
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CD40106_4001_4011_test.cir |
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491 Bytes |
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206 Time(s) |
_________________ "Let's make noise for peace." - Kijjaz |
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Uncle Krunkus
Moderator
Joined: Jul 11, 2005 Posts: 4761 Location: Sydney, Australia
Audio files: 52
G2 patch files: 1
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Posted: Wed Jun 27, 2012 4:34 pm Post subject:
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This great stuff Les.
Could be very useful for all manner of tests.
Where do you get it? _________________ What makes a space ours, is what we put there, and what we do there. |
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Inventor
Stream Operator
Joined: Oct 13, 2007 Posts: 6221 Location: near Austin, Tx, USA
Audio files: 267
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Posted: Wed Jun 27, 2012 4:42 pm Post subject:
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Uncle Krunkus wrote: | This great stuff Les.
Could be very useful for all manner of tests.
Where do you get it? |
Oh, I'm just having fun and I guess that leads to good things!
Les _________________ "Let's make noise for peace." - Kijjaz |
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Inventor
Stream Operator
Joined: Oct 13, 2007 Posts: 6221 Location: near Austin, Tx, USA
Audio files: 267
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Posted: Wed Jun 27, 2012 9:27 pm Post subject:
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OK, progress report. At this time all the logic works just fine, however I have been building D flip flop models for the CD4013 and CD4015 chips. The data sheet shows the schematics for these, which involve transmission gate feedback and feedforward, two-phase clocked. That's where the trouble arises because the DFF's components must be sized appropriately and I have little understanding of how to do this properly.
The CD4013 works well unloaded in forward propagation only. When i feed Qn back to D to make a TFF, the data just rails to VDD or VSS. I'm thinking that maybe I will also make some models that are not direct implementations at the transistor level, but are more behavioral models that simulate on a register transfer level rather than a transistor level.
Well, at least everything works fine in feedforward mode. That's something I guess...
Les _________________ "Let's make noise for peace." - Kijjaz |
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elmegil
Joined: Mar 20, 2012 Posts: 2177 Location: Chicago
Audio files: 16
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Posted: Wed Jun 27, 2012 9:57 pm Post subject:
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I'll echo the comments, these are excellent and I expect to be useful. |
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Inventor
Stream Operator
Joined: Oct 13, 2007 Posts: 6221 Location: near Austin, Tx, USA
Audio files: 267
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Inventor
Stream Operator
Joined: Oct 13, 2007 Posts: 6221 Location: near Austin, Tx, USA
Audio files: 267
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Posted: Thu Jun 28, 2012 3:07 am Post subject:
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Well I got some sleep and woke up fresh, realized that the transistors were of course improperly modeled with a knee at 2V rather than 1V. I changed them to 1V and resized some things a bit and fixed a wiring error, got the CD4013 and CD4015 models working - to a point.
Now they do work, indicating that the models are functional, but when I hook them up to other devices they fail. I suspect loading and timing issues that I will study soon. So, some good progress but still no cigar.
Les
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output of working simulation |
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This image has been reduced to fit the page. Click on it to enlarge. |
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test circuit with one cd4015 working correctly but not two and not with output resistors |
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CD4015_test.cir |
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867 Bytes |
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191 Time(s) |
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latest library file with major changes :) |
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CD4000em.lib |
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4.25 KB |
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215 Time(s) |
_________________ "Let's make noise for peace." - Kijjaz |
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