Re: gEDA-user: A little puzzled about the purpose of gschem
On Wed, 28 Apr 2010 14:48:40 -0600, asomers-Re5JQEeQqe8AvxtiuMwx3w wrote: I suggest the External Links section of the front page, Hmm, what front page? I can't seem to find External Links anywhere on gpleda.org. the text Spicelib provides a large library of spice models tested with Gnucap and NGSpice, and the URL www.h-renrew.de/h/spicelib/doc/index.html . I put a note in the simulation department of the geda wiki: http://geda.seul.org/wiki/geda:faq-simulation#where_are_the_models How about moving spicelib to gpleda.org? ---)kaimartin(--- -- Kai-Martin Knaak tel: +49-511-762-2895 Universität Hannover, Inst. für Quantenoptik fax: +49-511-762-2211 Welfengarten 1, 30167 Hannover http://www.iqo.uni-hannover.de GPG key:http://pgp.mit.edu:11371/pks/lookup?search=Knaak+kmkop=get ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Mon, May 3, 2010 at 11:33 AM, Kai-Martin Knaak k...@familieknaak.de wrote: On Wed, 28 Apr 2010 14:48:40 -0600, asomers-Re5JQEeQqe8AvxtiuMwx3w wrote: I suggest the External Links section of the front page, Hmm, what front page? I can't seem to find External Links anywhere on gpleda.org. The frontpage of http://www.gedasymbols.org/ I mean. I put a couple links on the gpleda.org wiki as well. the text Spicelib provides a large library of spice models tested with Gnucap and NGSpice, and the URL www.h-renrew.de/h/spicelib/doc/index.html . I put a note in the simulation department of the geda wiki: http://geda.seul.org/wiki/geda:faq-simulation#where_are_the_models How about moving spicelib to gpleda.org? As in hosting it there? Myself, I like the conveniences offered by Github, and I prefer to keep the source code there. As for web hosting, I think spicelib is currently on Werner Hoch's personal page. So you'd have to ask him, as the is the principal maintainer of the project. I haven't touched the web page at all. -Alan ---)kaimartin(--- -- Kai-Martin Knaak tel: +49-511-762-2895 Universität Hannover, Inst. für Quantenoptik fax: +49-511-762-2211 Welfengarten 1, 30167 Hannover http://www.iqo.uni-hannover.de GPG key: http://pgp.mit.edu:11371/pks/lookup?search=Knaak+kmkop=get ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Apr 28, 2010, at 9:41 PM, Dave McGuire wrote: On Apr 28, 2010, at 3:40 PM, John Doty wrote: Well, you started out complaining about a 741 model. I'd call that a very rare, obsolete part: I haven't actually seen one in a circuit in over 30 years. I guess it's still in textbooks (read Stephen J. Gould's rants about textbook authors' tendency to copy from previous textbooks sometime), but why would anyone use it in a new design? Very rare?! I see 741s everywhere. WTF? -Dave -- Dave McGuire Port Charlotte, FL ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user John Doty Noqsi Aerospace, Ltd. http://www.noqsi.com/ j...@noqsi.com ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Apr 28, 2010, at 9:41 PM, Dave McGuire wrote: Very rare?! I see 741s everywhere. WTF? Different worlds. You make my point. Why is anybody using anything so crummy in the 21st century? John Doty Noqsi Aerospace, Ltd. http://www.noqsi.com/ j...@noqsi.com ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
Gene Heskett wrote: On Wednesday 28 April 2010, Dave McGuire wrote: On Apr 28, 2010, at 3:40 PM, John Doty wrote: Well, you started out complaining about a 741 model. I'd call that a very rare, obsolete part: I haven't actually seen one in a circuit in over 30 years. I guess it's still in textbooks (read Stephen J. Gould's rants about textbook authors' tendency to copy from previous textbooks sometime), but why would anyone use it in a new design? Very rare?! I see 741s everywhere. WTF? -Dave Sorry to bust the bubble, but he's right. The 741 is well over 40 years old, and its open loop first response pole, where the 6db per octave rolloff begins, is a measly 10 hertz. The opamp is 1MHz unity BW. The higher the gain, the lower the first pole. An even better opamp would roll off at 1Hz. Today there are $1.00 opamps with a working gain of 20 when feedback is applied, with output slew rates of several thousand volts per second. Thats working bandwidth to several hundred megahertz at the sort of levels found in either a modern broadcast audio mixer, or a production video switcher, and either of those are driving 60 ohms for audio, or 75 for video. Those are video buffers. They have much less closed-loop gain and inferior offset voltages. They're also noisy and are very prone to oscillation with any stray capacitance or with certain feedback resistors. Slew rate limits alone in the 741 means you can't honestly ask it for more than a volt of output at full audio bandwidth. dV/dt = 2.pi.Vm at 20kHz and 1V/us, Vm=8Vpk quite ok for most apps below 5Vpk. At 3 volts the slew rate distortion is so bad even these 75 year old ears can hear it. Even a TLO-72 or 74 can mop the floor with a 741, and output a +- 15 volt rail to rail signal doing it, but into the old 600 ohm std load. LM741 has 1mV OS typical. TL072 is 3mV LM741 would be better than TL072 for control apps, and cheaper. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Thursday 29 April 2010, Dave McGuire wrote: On Apr 29, 2010, at 12:48 AM, Gene Heskett wrote: Well, you started out complaining about a 741 model. I'd call that a very rare, obsolete part: I haven't actually seen one in a circuit in over 30 years. I guess it's still in textbooks (read Stephen J. Gould's rants about textbook authors' tendency to copy from previous textbooks sometime), but why would anyone use it in a new design? Very rare?! I see 741s everywhere. WTF? Sorry to bust the bubble, but he's right. The 741 is well over 40 years old, and its open loop first response pole, where the 6db per octave rolloff begins, is a measly 10 hertz. Today there are $1.00 opamps with a working gain of 20 when feedback is applied, with output slew rates of several thousand volts per second. Thats working bandwidth to several hundred megahertz at the sort of levels found in either a modern broadcast audio mixer, or a production video switcher, and either of those are driving 60 ohms for audio, or 75 for video. Slew rate limits alone in the 741 means you can't honestly ask it for more than a volt of output at full audio bandwidth. At 3 volts the slew rate distortion is so bad even these 75 year old ears can hear it. Even a TLO-72 or 74 can mop the floor with a 741, and output a +- 15 volt rail to rail signal doing it, but into the old 600 ohm std load. No bubbles to bust, I'm not particularly fond of the 741...yes there are definitely better opamps out there (I usually use OP07s as my general-purpose opamp) but that doesn't change the fact that I see 741s everywhere. They are far (VERY far) from rare. -Dave At one point I had to replace some custom made on ceramic plates, op-amps in a Grass Valley 300-3A/B switcher, and GVG were being asses, wanting $1700 for one of them. I went to the catalogs found a to5 can that looked good, and put them into 3 failed channels of that production video switcher. They were so much faster, for $1.32 each, that it threw it out of color phase by about 10 degrees. If the removal and changeover hadn't been at least an hours work per channel, and I'd have had to replace about 48 of them all told, I would have. But we were then on notice that digital was coming, so that, originally $175,000 switcher was effectively in maintenance mode only. -- Cheers, Gene There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order. -Ed Howdershelt (Author) Your happiness is intertwined with your outlook on life. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Apr 29, 2010, at 6:50 AM, Russell Shaw wrote: Gene Heskett wrote: On Wednesday 28 April 2010, Dave McGuire wrote: On Apr 28, 2010, at 3:40 PM, John Doty wrote: Well, you started out complaining about a 741 model. I'd call that a very rare, obsolete part: I haven't actually seen one in a circuit in over 30 years. I guess it's still in textbooks (read Stephen J. Gould's rants about textbook authors' tendency to copy from previous textbooks sometime), but why would anyone use it in a new design? Very rare?! I see 741s everywhere. WTF? -Dave Sorry to bust the bubble, but he's right. The 741 is well over 40 years old, and its open loop first response pole, where the 6db per octave rolloff begins, is a measly 10 hertz. The opamp is 1MHz unity BW. The higher the gain, the lower the first pole. An even better opamp would roll off at 1Hz. Today there are $1.00 opamps with a working gain of 20 when feedback is applied, with output slew rates of several thousand volts per second. Thats working bandwidth to several hundred megahertz at the sort of levels found in either a modern broadcast audio mixer, or a production video switcher, and either of those are driving 60 ohms for audio, or 75 for video. Those are video buffers. They have much less closed-loop gain and inferior offset voltages. They're also noisy and are very prone to oscillation with any stray capacitance or with certain feedback resistors. Slew rate limits alone in the 741 means you can't honestly ask it for more than a volt of output at full audio bandwidth. dV/dt = 2.pi.Vm at 20kHz and 1V/us, Vm=8Vpk quite ok for most apps below 5Vpk. At 3 volts the slew rate distortion is so bad even these 75 year old ears can hear it. Even a TLO-72 or 74 can mop the floor with a 741, and output a +- 15 volt rail to rail signal doing it, but into the old 600 ohm std load. LM741 has 1mV OS typical. TL072 is 3mV LM741 would be better than TL072 for control apps, and cheaper. Yes, but there are much better devices for control apps than a 741, with its high power consumption, high bias current, and poor voltage ranges for common mode, output, and power. Indeed, there are so many that it's a pain to choose. What should I replace the obsolete OP220 with? Stepping back, this discussion reinforces the point I was trying to make. We frequently have newbies to gEDA complaining why doesn't gEDA support my common/standard needs straight out of installation?. But the universe here is large, and nobody sees more than a bit of it. What you see as essential depends on where you sit. When it comes to parts selection, Gene thinks audio/video because that's what he works with. You seem to be cost sensitive. I'm a scientific instrument designer: parts cost is usually a negligible part of the budget, but noise and power are a big deal. We look at this stuff different ways. Moving from parts selection to the broader issues of EDA, we again see a great deal of diversity. There really are no common/standard needs beyond the basics that gEDA does pretty well. If you believe that there are, I think you need to broaden your horizons. gEDA's unique strength is that it supports that diversity well. John Doty Noqsi Aerospace, Ltd. http://www.noqsi.com/ j...@noqsi.com ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Thursday 29 April 2010, Russell Shaw wrote: Gene Heskett wrote: On Wednesday 28 April 2010, Dave McGuire wrote: On Apr 28, 2010, at 3:40 PM, John Doty wrote: Well, you started out complaining about a 741 model. I'd call that a very rare, obsolete part: I haven't actually seen one in a circuit in over 30 years. I guess it's still in textbooks (read Stephen J. Gould's rants about textbook authors' tendency to copy from previous textbooks sometime), but why would anyone use it in a new design? Very rare?! I see 741s everywhere. WTF? -Dave Sorry to bust the bubble, but he's right. The 741 is well over 40 years old, and its open loop first response pole, where the 6db per octave rolloff begins, is a measly 10 hertz. The opamp is 1MHz unity BW. The higher the gain, the lower the first pole. An even better opamp would roll off at 1Hz. Today there are $1.00 opamps with a working gain of 20 when feedback is applied, with output slew rates of several thousand volts per second. Thats working bandwidth to several hundred megahertz at the sort of levels found in either a modern broadcast audio mixer, or a production video switcher, and either of those are driving 60 ohms for audio, or 75 for video. Those are video buffers. They have much less closed-loop gain and inferior offset voltages. They're also noisy and are very prone to oscillation with any stray capacitance or with certain feedback resistors. I believe that to be an artifact of the GB product not being high enough in what was available, say back in LM-357 days. When I replaced some custom made discreet op-amps in that grass switcher with some fairly modern internally compensated ones with a GB of about 10Ghz, it was absolutely not a problem. They were the ideal block of gain dead stable despite a layout when being used to sub for something else, that would give a modern video engineer recurring nightmares. Flying leads up to an inch long just to reach the original plates mounting and connecting holes in the PCB. That had kludge written all over it, but it technically kicked ass compared to the much slower discreet versions grass wanted $1700/copy for. Slew rate limits alone in the 741 means you can't honestly ask it for more than a volt of output at full audio bandwidth. dV/dt = 2.pi.Vm at 20kHz and 1V/us, Vm=8Vpk quite ok for most apps below 5Vpk. At 3 volts the slew rate distortion is so bad even these 75 year old ears can hear it. Even a TLO-72 or 74 can mop the floor with a 741, and output a +- 15 volt rail to rail signal doing it, but into the old 600 ohm std load. LM741 has 1mV OS typical. TL072 is 3mV Can you hear 3mv dc? LM741 would be better than TL072 for control apps, and cheaper. Maybe so, but with 4 of then in a dip, and room for 22 cards in the cage, I used them in multi-tube quantities (5 per card, 22 cards) for utility audio DA's at WDTV-5 for nearly 20 years. Most failures were on longer output run circuits, and lightening related. When you have a 255 foot tower 30 feet out the back door, the emp pulse from a lightning strike is considerable, and tends to knock out the output stages. So I designed one with some to5 outputs to buffer the chip output, and they had an even shorter life plus they crowbared the whole cage supply when they failed, much more catastrophic in effect as that didn't just cost us one audio src, it took us off the air. The old favorite burn your fingers power hog op-amp, 5532 would fail at 20x that rate under the same conditions. In broadcast, you learn to use what gets the job done with audio performance that is adequate, and is the _most_ dependable. Getting rid of that last .001% of distortion is not a priority that even makes the list. However, 25volts p-p at 20 khz with no slew rate or cross-over discernible on a 100mhz scope, or at lower frequencies my ears could hear well was good enough for the girls I went with. -- Cheers, Gene There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order. -Ed Howdershelt (Author) dracus Ctrl+Option+Command + P + R Knghtbrd dracus - YE GODS! That's worse than EMACS! LauraDax hehehehe dracus don't ask what that does :P ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Thursday 29 April 2010, John Doty wrote: On Apr 29, 2010, at 6:50 AM, Russell Shaw wrote: Gene Heskett wrote: On Wednesday 28 April 2010, Dave McGuire wrote: On Apr 28, 2010, at 3:40 PM, John Doty wrote: Well, you started out complaining about a 741 model. I'd call that a very rare, obsolete part: I haven't actually seen one in a circuit in over 30 years. I guess it's still in textbooks (read Stephen J. Gould's rants about textbook authors' tendency to copy from previous textbooks sometime), but why would anyone use it in a new design? Very rare?! I see 741s everywhere. WTF? -Dave Sorry to bust the bubble, but he's right. The 741 is well over 40 years old, and its open loop first response pole, where the 6db per octave rolloff begins, is a measly 10 hertz. The opamp is 1MHz unity BW. The higher the gain, the lower the first pole. An even better opamp would roll off at 1Hz. Today there are $1.00 opamps with a working gain of 20 when feedback is applied, with output slew rates of several thousand volts per second. Thats working bandwidth to several hundred megahertz at the sort of levels found in either a modern broadcast audio mixer, or a production video switcher, and either of those are driving 60 ohms for audio, or 75 for video. Those are video buffers. They have much less closed-loop gain and inferior offset voltages. They're also noisy and are very prone to oscillation with any stray capacitance or with certain feedback resistors. Slew rate limits alone in the 741 means you can't honestly ask it for more than a volt of output at full audio bandwidth. dV/dt = 2.pi.Vm at 20kHz and 1V/us, Vm=8Vpk quite ok for most apps below 5Vpk. At 3 volts the slew rate distortion is so bad even these 75 year old ears can hear it. Even a TLO-72 or 74 can mop the floor with a 741, and output a +- 15 volt rail to rail signal doing it, but into the old 600 ohm std load. LM741 has 1mV OS typical. TL072 is 3mV LM741 would be better than TL072 for control apps, and cheaper. Yes, but there are much better devices for control apps than a 741, with its high power consumption, high bias current, and poor voltage ranges for common mode, output, and power. Indeed, there are so many that it's a pain to choose. What should I replace the obsolete OP220 with? What was it trying to do? That will have a heavy bearing on the replacement choice. Stepping back, this discussion reinforces the point I was trying to make. We frequently have newbies to gEDA complaining why doesn't gEDA support my common/standard needs straight out of installation?. But the universe here is large, and nobody sees more than a bit of it. What you see as essential depends on where you sit. When it comes to parts selection, Gene thinks audio/video because that's what he works with. You seem to be cost sensitive. I'm a scientific instrument designer: parts cost is usually a negligible part of the budget, but noise and power are a big deal. We look at this stuff different ways. Quite so John. In my case parts costs were escalated because Grass thought (erroneously) that they had us by the whole bag, not just the short hairs. So, not knowing any better, I just did it. With excellent results. We differ also in career outlooks I suspect John. You are no doubt, from what I've read on this list for quite some time, a 'papered' engineer, with a heavy background in the math involved and are quite capable to ripping some of my arguments to shreds. I OTOH, was a boy geek before the word was invented and quit school to go fix these newfangled tv's in '48. Math was not one of my strong points, I learned more about the higher functions from an early TI calculator purchase than I ever got in formal schooling. I have been making electrons do as they are told since, although at 75, not for a living anymore. Making the switch to broadcast engineering in the early 60's narrowed my field of view and allowed me to get a much more closeup view, which was helpful. That 'specialization' has allowed me to be fairly well paid as the CE for the last 26 years. It has also gotten me accused of walking on water a few times. ;-) Moving from parts selection to the broader issues of EDA, we again see a great deal of diversity. There really are no common/standard needs beyond the basics that gEDA does pretty well. If you believe that there are, I think you need to broaden your horizons. +1 gEDA's unique strength is that it supports that diversity well. John Doty Noqsi Aerospace, Ltd. http://www.noqsi.com/ j...@noqsi.com -- Cheers, Gene There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order. -Ed Howdershelt (Author) Mercury At that point it will compile, but segfault, as it should.. ___ geda-user mailing list geda-user@moria.seul.org
Re: gEDA-user: A little puzzled about the purpose of gschem
On Apr 29, 2010, at 8:03 AM, John Doty wrote: Very rare?! I see 741s everywhere. WTF? Different worlds. You make my point. Why is anybody using anything so crummy in the 21st century? Most of them that I see are at least ten years old. That said, they're cheap, readily available everywhere (even Radio Shack!), and SPICE models are easy to find. Not every company has aerospace budgets. ;) -Dave -- Dave McGuire Port Charlotte, FL ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Apr 29, 2010, at 8:34 AM, Gene Heskett wrote: What should I replace the obsolete OP220 with? What was it trying to do? That will have a heavy bearing on the replacement choice. Mainly not waste too much power ;-) I used these for a variety of low power, low speed, moderately high voltage purposes. For example: Translating CMOS DAC outputs to higher and/or bipolar ranges. Buffering DC test points and temperature sensors. Thermal control loops. One advantage was that RQA was reasonably happy with this choice, partly because it was available in a brittle ceramic package that was supposedly more reliable than plastic. I'm tentatively going with LT1078 for new designs. We'll see how loudly RQA complains... John Doty Noqsi Aerospace, Ltd. http://www.noqsi.com/ j...@noqsi.com ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
John Doty wrote: On Apr 28, 2010, at 9:41 PM, Dave McGuire wrote: Very rare?! I see 741s everywhere. WTF? Different worlds. You make my point. Why is anybody using anything so crummy in the 21st century? Perhaps, like me they have a pile of them. I'm staring at about 25 of them right now. ;) Jim. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Sat, Apr 24, 2010 at 6:40 PM, John Doty [1]...@noqsi.com wrote: On Apr 24, 2010, at 7:16 PM, Madhusudan Singh wrote: Failure to correspond to your prejudices is not imperfection. Needing an extra 20 minutes after wiring the net, to populate spice models for each gschem schematic (instead of having a set of default libraries that do that for common circuit elements) for each circuit, I really don't think you understand how the process works. Can you post a schematic? All you should be doing is attaching model-name= and perhaps file= (although I prefer to include a library once) to active components. Not so hard. Harder than having a proper library that allows me to focus on the circuit design instead of these kinds of clerical tasks that appear to arise from an utter lack of understanding that human beings do not like to do mundane, repetitive tasks that are best suited for the software to take care of. While we are on the subject, just typing up the entire spice netlist from scratch in a single window is not hard (and arguably easier than scattering it all over the place the way things are set up now) either. I can get faster results from MacSpice than this artificially convoluted gschem + patchwork + gnetlist workflow. I can understand that you have some emotions invested in geda for whatever reason, but your statement above made absolutely no sense. What you consider common circuit elements are undoubtedly different from what I commonly use. That's how it goes. You have to build your own library, just like I had to when I was using Pspice back in the '90s. Which is precisely the problem. This isn't the 90s. I grew up on BBC microcomputers. Do I feel nostalgic about the things I used to be able to do with those beauties ? Yes. Do I think that the associated workflow with them was superior to the workflow today (even with something as unreliable as Windows) ? Not a chance. compared to spending 0 extra minutes on something like LTSpice or PSpice is not prejudice. It is 20 minutes of wasted time. Of course, I have a decided prejudice against wasted time of that sort. So, very prejudicially, I view it as an imperfection. The real time wasters aren't the setup, but the the repeated manual operations of GUI tools. Thanks for buttressing my argument: 1. If GUI tools are the problem, why use gschem at all ? 2. If repetition is the problem, why the defense of the current workflow that requires repetition of the task of putting in pieces of spice script in different pretty little boxes ? Even MacSpice is better than that. You do have an interesting definition of productivity then. But no matter. Given that I've designed 6000 transistor VLSI chips and 1000 component circuit boards with gschem, I think I understand its productivity. You have to use the power of the toolkit, not struggle against it. Or use a better toolkit that takes that needless, wasteful, and professionally irrelevant struggle out of the equation. References 1. mailto:j...@noqsi.com ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
Most tools require some preliminary investment in terms of setting up libraries to the satisfaction of the user, plus general familiarisation. I think you will find you only need to modify your symbol once to include the appropriate SPICE directives. If you save this symbol you can then reuse it (not trying to make you suck eggs here but this argument seems stalled to the point of stating the obvious). The purpose of gschem does not include containing a library of symbols that include all possible spice and pcb footprint information. gEDA includes gattrib to ease the process of customising symbols - this is not the only method of adding/editing attributes though. Comparing gEDA with LTSpice is a bit odd once you understand the purpose of gEDA. LTSpice by definition has all the SPICE information for all its library components - but I'll warrent it has very little information about component footprints. gEDA is much more powerful and versatile than LTSpice but does require you to do a bit of manual work to begin with. There is discussion about creating a database separate to gschem that may in the future provide SPICE symbol data for standard components. Depending on how this is integrated into the workflow, perhaps this would ease your concerns. Not much help at this stage though... All the best, Geoff ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Apr 28, 2010, at 12:41 AM, Madhusudan Singh wrote: On Sat, Apr 24, 2010 at 6:40 PM, John Doty [1]...@noqsi.com wrote: On Apr 24, 2010, at 7:16 PM, Madhusudan Singh wrote: Failure to correspond to your prejudices is not imperfection. Needing an extra 20 minutes after wiring the net, to populate spice models for each gschem schematic (instead of having a set of default libraries that do that for common circuit elements) for each circuit, I really don't think you understand how the process works. Can you post a schematic? All you should be doing is attaching model-name= and perhaps file= (although I prefer to include a library once) to active components. Not so hard. Harder than having a proper library that allows me to focus on the circuit design instead of these kinds of clerical tasks that appear to arise from an utter lack of understanding that human beings do not like to do mundane, repetitive tasks that are best suited for the software to take care of. And gEDA is better at doing the mundane, repetitive tasks than other systems. Once you have your processes set up, a single make can generate netlists, BOM, simulation results, printable schematics, typeset documentation... While we are on the subject, just typing up the entire spice netlist from scratch in a single window is not hard (and arguably easier than scattering it all over the place the way things are set up now) either. I can't imagine doing that for one of my VLSI designs: I could never get it right. But I don't have to. I can get faster results from MacSpice than this artificially convoluted gschem + patchwork + gnetlist workflow. Will you please show us your work? Apparently you're doing it in some convoluted way that makes it unusually hard. Yes, gEDA will let you make your processes as difficult as you want, but that's *your* choice, not the property of the tool. I can understand that you have some emotions invested in geda for whatever reason, but your statement above made absolutely no sense. What you consider common circuit elements are undoubtedly different from what I commonly use. That's how it goes. You have to build your own library, just like I had to when I was using Pspice back in the '90s. Which is precisely the problem. This isn't the 90s. I grew up on BBC microcomputers. Do I feel nostalgic about the things I used to be able to do with those beauties ? Yes. Do I think that the associated workflow with them was superior to the workflow today (even with something as unreliable as Windows) ? Not a chance. I'm sure Pspice users have the same problems today, only worse, since the component choices are much wider. compared to spending 0 extra minutes on something like LTSpice or PSpice is not prejudice. It is 20 minutes of wasted time. Of course, I have a decided prejudice against wasted time of that sort. So, very prejudicially, I view it as an imperfection. The real time wasters aren't the setup, but the the repeated manual operations of GUI tools. Thanks for buttressing my argument: 1. If GUI tools are the problem, why use gschem at all ? As I have said many times on this forum, GUI is suitable for interactions between humans and computers when those interactions are inherently graphical. But GUI is not a good way to *automate* processes that the computer can do by itself. 2. If repetition is the problem, why the defense of the current workflow that requires repetition of the task of putting in pieces of spice script in different pretty little boxes ? For a subcircuit schematic you need a box that effectively says this is a subcircuit with name Other than that, you need no boxes, although sometimes they are convenient. So your problem would seem to be that you don't understand the toolkit. Perhaps the documentation needs improving. Grab the development project from http://www.gedasymbols.org/user/john_doty/models/opamp/index.html and try it out. It's pretty easy, I think, although at this level of simplicity you don't really see the full power of a scripted gEDA flow. A few pretty little boxes in the schematics, but they were hardly difficult to create. The two in the top level schematic could be combined if I wanted, so there'd just be one per schematic. For one of my projects, I have a specialized program (not part of gEDA) that creates an elaborate simulation script, typically ~500 kilobytes, mostly PWM() source data. All I have to do is type make chaintest and the Makefile generates the simulation netlists from the gEDA schematics, runs the program to create the simulation script, concatenates the generated simulation script and another much simpler fixed script to the top level netlist, invokes ngspice, and when that finishes runs a pipeline of specialized programs to reduce the massive output of ngspice (up to 20
Re: gEDA-user: A little puzzled about the purpose of gschem
-Original Message- From: geda-user-boun...@moria.seul.org [mailto:geda-user-boun...@moria.seul.org] On Behalf Of John Doty Sent: Wednesday, April 28, 2010 6:40 AM To: gEDA user mailing list Subject: Re: gEDA-user: A little puzzled about the purpose of gschem ... Harder than having a proper library that allows me to focus on the circuit design instead of these kinds of clerical tasks that appear to arise from an utter lack of understanding that human beings do not like to do mundane, repetitive tasks that are best suited for the software to take care of. And gEDA is better at doing the mundane, repetitive tasks than other systems. Once you have your processes set up, a single make can generate netlists, BOM, simulation results, printable schematics, typeset documentation... How long did it take you to learn make well enough to do this with it? How long does it take you to set up your processes for any given project? ... Or use a better toolkit that takes that needless, wasteful, and professionally irrelevant struggle out of the equation. If you're struggling, you're not using the tool effectively. Show us your work. We can help you, and when we figure out why you're puzzled maybe we can improve the documentation. But to a newbie, learning to use a tool effectively if its only power is at a command line, takes a loong time, and much referring to a separate reference of some kind to find the needed command. A gui, while it can be limiting to an expert, will often speed up that initial learning curve, especially if it's just a wrapper around a command-line or other interface, so the newbie can use it to learn the capabilities and commands that the command-line uses. D ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Apr 28, 2010, at 5:54 AM, David C. Kerber wrote: -Original Message- From: geda-user-boun...@moria.seul.org [mailto:geda-user-boun...@moria.seul.org] On Behalf Of John Doty Sent: Wednesday, April 28, 2010 6:40 AM To: gEDA user mailing list Subject: Re: gEDA-user: A little puzzled about the purpose of gschem ... Harder than having a proper library that allows me to focus on the circuit design instead of these kinds of clerical tasks that appear to arise from an utter lack of understanding that human beings do not like to do mundane, repetitive tasks that are best suited for the software to take care of. And gEDA is better at doing the mundane, repetitive tasks than other systems. Once you have your processes set up, a single make can generate netlists, BOM, simulation results, printable schematics, typeset documentation... How long did it take you to learn make well enough to do this with it? Oh, maybe 20 minutes. Make is easy. Best to start with S.I. Feldman's great original writeup: it's all over the web, for example at: www.hpdc.syr.edu/~chapin/cis657/make.pdf Meditate for a minute on how we've lost the ability to write so clearly and concisely. Then go to your more modern make doc to pick up knowledge of the more modern version of implicit rules (easier and more flexible). That'll do you. How long does it take you to set up your processes for any given project? Depends on the scale of the project. It's a small fraction of the project time. Yes, it's annoying work, not comfortably mindless point and click, but it saves bundles of time. And that's the emotional issue: point and click is *comfortable*, scripting isn't. So users don't notice how much time is wasted pointing and clicking, but are annoyed by even a few minutes of trivial Makefile programming. ... Or use a better toolkit that takes that needless, wasteful, and professionally irrelevant struggle out of the equation. If you're struggling, you're not using the tool effectively. Show us your work. We can help you, and when we figure out why you're puzzled maybe we can improve the documentation. But to a newbie, learning to use a tool effectively if its only power is at a command line, takes a loong time, and much referring to a separate reference of some kind to find the needed command. The pricey professional tools are hard to learn. Been there, done that, gEDA's easier. A gui, while it can be limiting to an expert, will often speed up that initial learning curve, especially if it's just a wrapper around a command-line or other interface, so the newbie can use it to learn the capabilities and commands that the command-line uses. Wrap the tools all you want, that's a fine example of factoring. But don't, for example, put kludges into gschem itself to support a specific flow. We already have specialized kludges in gnetlist to support VAMS. One worthy project would be to rewrite these in Guile in the VAMS back end, perhaps refactoring gnetlist to support this. John Doty Noqsi Aerospace, Ltd. http://www.noqsi.com/ j...@noqsi.com ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
David C. Kerber wrote: Harder than having a proper library that allows me to focus on the circuit design instead of these kinds of clerical tasks that appear to arise from an utter lack of understanding that human beings do not like to do mundane, repetitive tasks that are best suited for the software to take care of. And gEDA is better at doing the mundane, repetitive tasks than other systems. Once you have your processes set up, a single make can generate netlists, BOM, simulation results, printable schematics, typeset documentation... How long did it take you to learn make well enough to do this with it? I'm not John, but understanding make enough, to describe a linear or tree-shaped flow requires reading of about 5-15 pages describing syntax and remebering 3 basic things: - to the left of the : in a rule is what I want to get from that rule (the target) - to the right of the : are the ingredients - the script-piece below the rule is the recipe, how to make the result out of the ingredients; usually a command or sequence of commands. This can be cascaded ad infinitum. All the complicated rest of make is about how to parametrize and generalise these 3-part rules and achieve behaviours that deviate from the simple priciples. How long does it take you to set up your processes for any given project? eventually depends on the project, but so far my geda makefile looks like this: -- cut here - zip: zip lichttisch_`date -I`.zip *.sch *.net *.pcb *.gbr *.cnc -- cut again --- It has a single target named zip that depends on nothing. The target does not create a file called zip so it will always invoke it's script when called. So if I want to create the zip-file of todays snapshot for backup I type 'make zip' Actually typing 'make' would be sufficient, since the 1st target in a makefile is the default. Make was developed to automate hierarchical builds, so it checks the age of file(s) described by a target to the age of all ingredients and invokes the corresponding build script, only if at least one of the ingredients is newer than the target. But to a newbie, learning to use a tool effectively if its only power is at a command line, takes a loong time, and much referring to a separate reference of some kind to find the needed command. A gui, while it can be limiting to an expert, will often speed up that initial learning curve, especially if it's just a wrapper around a command-line or other interface, so the newbie can use it to learn the capabilities and commands that the command-line uses. This took me a few minutes to write. How long did you need to read and understand it? ;-) Armin ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
Thanks for a reasonable response to my post. Yes, an initial investment is often needed, but that ought to be an investment that deals with non-standard components that are not of common interest. Second, before your response, no one (at least as I read it) said that you could save the spice directives with the symbol itself. People talked about copying and pasting things from an existing schematic, but that is not the same thing. This rekindles my interest in gschem. One followup question - is it possible to pack symbols with commonly used public domain spice models and create a library that other users of gschem can employ (and would then be able to use without all that initial investment of time) ? If yes, why has no one ever done it (the project is pretty mature) ? If no, what are the legal / technical reasons for that choice ? Its not just LTSpice. kicad (not that I have used it, but reading from the descriptions) supposedly also does a more seamless spice simulation AND has pcb layout tools integrated. Not embedding the commonly available spice models for common components appears to be a retrograde choice for gschem. But I am happy to hear that the symbols can be saved with the model itself. Whether or not a proper shared library can be created is a different matter. On Wed, Apr 28, 2010 at 12:23 AM, Geoff Swan [1]shinobi.j...@gmail.com wrote: Most tools require some preliminary investment in terms of setting up libraries to the satisfaction of the user, plus general familiarisation. I think you will find you only need to modify your symbol once to include the appropriate SPICE directives. If you save this symbol you can then reuse it (not trying to make you suck eggs here but this argument seems stalled to the point of stating the obvious). The purpose of gschem does not include containing a library of symbols that include all possible spice and pcb footprint information. gEDA includes gattrib to ease the process of customising symbols - this is not the only method of adding/editing attributes though. Comparing gEDA with LTSpice is a bit odd once you understand the purpose of gEDA. LTSpice by definition has all the SPICE information for all its library components - but I'll warrent it has very little information about component footprints. gEDA is much more powerful and versatile than LTSpice but does require you to do a bit of manual work to begin with. There is discussion about creating a database separate to gschem that may in the future provide SPICE symbol data for standard components. Depending on how this is integrated into the workflow, perhaps this would ease your concerns. Not much help at this stage though... All the best, Geoff ___ geda-user mailing list [2]geda-u...@moria.seul.org [3]http://www.seul.org/cgi-bin/mailman/listinfo/geda-user References 1. mailto:shinobi.j...@gmail.com 2. mailto:geda-user@moria.seul.org 3. http://www.seul.org/cgi-bin/mailman/listinfo/geda-user ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
The problem is that there are very few public-domain spice models. Every semiconductor vendor has their own license (sometimes several) for their spice libraries. Only some of these licenses allow redistribution. Furthermore, because the licenses are carelessly written and applied, they are often legally ambiguous. Yet more pain comes from their incompatibilities; no two spice simulators are 100% compatible, so most (in my experience) vendor-provided models do not work with the open-source simulators. Spicelib (http://www.h-renrew.de/h/spicelib/doc/index.html), which I shall shamelessly plug for the 3rd time on this thread, tries to solve both of these problems. It is a set of scripts that a user can download. The scripts will fetch vendors' models directly from the source, solving the redistribution problem. Then it will patch them for compatibility with gnucap and ng-spice, solving the compatibility problem. Spicelib is still rough around the edges, but it's a quick way to get ~1500 tested spice models that you can use. It does not, however, come with a set of gschem symbols. There is no reason why someone can't create a library of symbols that reference the spicelib models. However, many (most?) gschem users don't want this. A one-size-fits-all symbol just doesn't satisfy everyone's needs. While it's nice for hobbyists and students, most professionals have very detailed requirements and would be unable to use such a premade library. For professionals, gschem's builtin light symbols are more useful, because they can be easily adapted to specific needs. This is also why expensive EDA software typically doesn't come with premade symbol libraries. But I agree, hobbyists would rejoice at the availability of such a library. http://www.gedasymbols.org/ is the closest thing we have right now. On Wed, Apr 28, 2010 at 12:34 PM, Madhusudan Singh singh.madhusu...@gmail.com wrote: Thanks for a reasonable response to my post. Yes, an initial investment is often needed, but that ought to be an investment that deals with non-standard components that are not of common interest. Second, before your response, no one (at least as I read it) said that you could save the spice directives with the symbol itself. People talked about copying and pasting things from an existing schematic, but that is not the same thing. This rekindles my interest in gschem. One followup question - is it possible to pack symbols with commonly used public domain spice models and create a library that other users of gschem can employ (and would then be able to use without all that initial investment of time) ? If yes, why has no one ever done it (the project is pretty mature) ? If no, what are the legal / technical reasons for that choice ? Its not just LTSpice. kicad (not that I have used it, but reading from the descriptions) supposedly also does a more seamless spice simulation AND has pcb layout tools integrated. Not embedding the commonly available spice models for common components appears to be a retrograde choice for gschem. But I am happy to hear that the symbols can be saved with the model itself. Whether or not a proper shared library can be created is a different matter. On Wed, Apr 28, 2010 at 12:23 AM, Geoff Swan [1]shinobi.j...@gmail.com wrote: Most tools require some preliminary investment in terms of setting up libraries to the satisfaction of the user, plus general familiarisation. I think you will find you only need to modify your symbol once to include the appropriate SPICE directives. If you save this symbol you can then reuse it (not trying to make you suck eggs here but this argument seems stalled to the point of stating the obvious). The purpose of gschem does not include containing a library of symbols that include all possible spice and pcb footprint information. gEDA includes gattrib to ease the process of customising symbols - this is not the only method of adding/editing attributes though. Comparing gEDA with LTSpice is a bit odd once you understand the purpose of gEDA. LTSpice by definition has all the SPICE information for all its library components - but I'll warrent it has very little information about component footprints. gEDA is much more powerful and versatile than LTSpice but does require you to do a bit of manual work to begin with. There is discussion about creating a database separate to gschem that may in the future provide SPICE symbol data for standard components. Depending on how this is integrated into the workflow, perhaps this would ease your concerns. Not much help at this stage though... All the best, Geoff ___ geda-user mailing list
Re: gEDA-user: A little puzzled about the purpose of gschem
On Apr 28, 2010, at 12:34 PM, Madhusudan Singh wrote: Thanks for a reasonable response to my post. Yes, an initial investment is often needed, but that ought to be an investment that deals with non-standard components that are not of common interest. Well, you started out complaining about a 741 model. I'd call that a very rare, obsolete part: I haven't actually seen one in a circuit in over 30 years. I guess it's still in textbooks (read Stephen J. Gould's rants about textbook authors' tendency to copy from previous textbooks sometime), but why would anyone use it in a new design? You and I probably cannot agree on what components are of common interest, and if we bring in a third party I'd expect yet another completely different viewpoint. Second, before your response, no one (at least as I read it) said that you could save the spice directives with the symbol itself. People talked about copying and pasting things from an existing schematic, but that is not the same thing. gEDA is, above all, very flexible. There are a number of ways to accomplish most tasks. You seem to have found one of the more difficult ones (but I still don't understand your difficulty). This rekindles my interest in gschem. One followup question - is it possible to pack symbols with commonly used public domain spice models and create a library that other users of gschem can employ (and would then be able to use without all that initial investment of time) ? Sure. The jargon is heavy symbols. If yes, why has no one ever done it (the project is pretty mature) ? 1. It would take a huge library of symbols to satisfy everybody's desire for their own version of components of common interest. 2. There are few commonly used public domain spice models, so the library would necessarily be very incomplete. It's free software. Someone would have to volunteer to do this. I suspect nobody has because anybody who could actually do it understands the massive size of the library that would need to be generated, and the lack of freely publishable models. If no, what are the legal / technical reasons for that choice ? You are welcome to contribute here. Get DJ to give you an account at gedasymbols.org. Your ambition is impossible, but partial success would still be valuable progress. Beware that DJ will be vexed with you if you pirate intellectual property: be sure you violate neither the model owner's license terms nor the GPL's restrictions on compatible licensing. Its not just LTSpice. kicad (not that I have used it, but reading from the descriptions) supposedly also does a more seamless spice simulation AND has pcb layout tools integrated. They also can't go most of the places gEDA can go. Perhaps you don't care, but gEDA's flexibility is essential to me. Nobody does VLSI design with LTSpice or kicad. Nobody captures schematics for symbolic circuit analysis with them either. But gEDA can do those things. Type man gnetlist for a glimpse at the variety of data products gEDA can export (and it's easy to add more with user Guile scripts). What other toolkit can do this? Not embedding the commonly available spice models for common components appears to be a retrograde choice for gschem. Most commonly available models cannot be legally embedded in distributed symbols since most have restrictive licenses. Note that for big, complex simulations, embedding models in symbols is undesirable because it places a separate copy of the model in the simulation for each component instance. ngspice, at least, handles a reference to a single instance of a library model much more efficiently than a copy of the model for each component instance. In extreme cases I've even seen this problem reveal memory management difficulties in ngspice, resulting in segfaults. But for small, simple simulations, you may prefer models embedded in symbols. gEDA can handle this either way: that's the kind of advantage flexibility brings. John Doty Noqsi Aerospace, Ltd. http://www.noqsi.com/ j...@noqsi.com ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Apr 28, 2010, at 1:26 PM, asom...@gmail.com wrote: Spicelib (http://www.h-renrew.de/h/spicelib/doc/index.html), which I shall shamelessly plug for the 3rd time on this thread, tries to solve both of these problems. It is a set of scripts that a user can download. The scripts will fetch vendors' models directly from the source, solving the redistribution problem. Then it will patch them for compatibility with gnucap and ng-spice, solving the compatibility problem. Might be good to put a link to this on gedasymbols.org. Maybe also get Ales to put one on gpleda.org and Stuart to put one in his spice-sdb document. John Doty Noqsi Aerospace, Ltd. http://www.noqsi.com/ j...@noqsi.com ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
Might be good to put a link to this on gedasymbols.org. Please suggest a specific location, text, and url for such a link. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
We already have specialized kludges in gnetlist to support VAMS. One worthy project would be to rewrite these in Guile in the VAMS back end, perhaps refactoring gnetlist to support this. Let me see the vams code... Boehhoee, that's about 60 lines of code that gives you reduced functionality! But I see an opportunity for you: rename those two functions to something generic, maybe even create _one_ function. Less is more! Don't forget to change g_register.c, prototype.h and put the old vams function name in gnetlist.scm, please make users aware that the vams function is deprecated (e.g. display a message). You didn't forget to change the Makefile.in before compilation? More importantly: when you change the function names, put some doxygen comments above the function. Oh, move it to g_netlist.c. One source file less and increased flexi-functionality! When you are there, you could document all your familiar gnetlist/guile procedures. I'm wondering what scary things you find in g_netlist.c when you are writing documentation for that part of the gnetlist interface. You don't forget to document g_rc.c when completing the documentation? Finally gnetlist gets a documented interface, really useful for new script writers. Yeah, gnetlist gets some love from mr. Doty! Or not... Bas Gieltjes -- ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
I suggest the External Links section of the front page, the text Spicelib provides a large library of spice models tested with Gnucap and NGSpice, and the URL www.h-renrew.de/h/spicelib/doc/index.html . Also, thanks for writing DJGPP so long ago. I'm still using CWSDPMI at work on my DOS machine. -Alan On Wed, Apr 28, 2010 at 2:18 PM, DJ Delorie d...@delorie.com wrote: Might be good to put a link to this on gedasymbols.org. Please suggest a specific location, text, and url for such a link. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Apr 28, 2010, at 2:20 PM, Bas Gieltjes wrote: We already have specialized kludges in gnetlist to support VAMS. One worthy project would be to rewrite these in Guile in the VAMS back end, perhaps refactoring gnetlist to support this. Let me see the vams code... Boehhoee, that's about 60 lines of code that gives you reduced functionality! The road to Hell is taken in single steps. But I see an opportunity for you: rename those two functions to something generic, maybe even create _one_ function. Less is more! Don't forget to change g_register.c, prototype.h and put the old vams function name in gnetlist.scm, please make users aware that the vams function is deprecated (e.g. display a message). Nah, just move it into the back end. You didn't forget to change the Makefile.in before compilation? More importantly: when you change the function names, put some doxygen comments above the function. Oh, move it to g_netlist.c. One source file less and increased flexi-functionality! When you are there, you could document all your familiar gnetlist/guile procedures. Been working on that. I'm wondering what scary things you find in g_netlist.c when you are writing documentation for that part of the gnetlist interface. You don't forget to document g_rc.c when completing the documentation? Finally gnetlist gets a documented interface, really useful for new script writers. Yep, it's a lot of work, not made easier by having too much code on the C side. Yeah, gnetlist gets some love from mr. Doty! Or not... It won't get as much as it really needs. Still, it's a remarkably good tool. Bas Gieltjes -- ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user John Doty Noqsi Aerospace, Ltd. http://www.noqsi.com/ j...@noqsi.com ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Apr 28, 2010, at 3:40 PM, John Doty wrote: Well, you started out complaining about a 741 model. I'd call that a very rare, obsolete part: I haven't actually seen one in a circuit in over 30 years. I guess it's still in textbooks (read Stephen J. Gould's rants about textbook authors' tendency to copy from previous textbooks sometime), but why would anyone use it in a new design? Very rare?! I see 741s everywhere. WTF? -Dave -- Dave McGuire Port Charlotte, FL ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Wednesday 28 April 2010, Dave McGuire wrote: On Apr 28, 2010, at 3:40 PM, John Doty wrote: Well, you started out complaining about a 741 model. I'd call that a very rare, obsolete part: I haven't actually seen one in a circuit in over 30 years. I guess it's still in textbooks (read Stephen J. Gould's rants about textbook authors' tendency to copy from previous textbooks sometime), but why would anyone use it in a new design? Very rare?! I see 741s everywhere. WTF? -Dave Sorry to bust the bubble, but he's right. The 741 is well over 40 years old, and its open loop first response pole, where the 6db per octave rolloff begins, is a measly 10 hertz. Today there are $1.00 opamps with a working gain of 20 when feedback is applied, with output slew rates of several thousand volts per second. Thats working bandwidth to several hundred megahertz at the sort of levels found in either a modern broadcast audio mixer, or a production video switcher, and either of those are driving 60 ohms for audio, or 75 for video. Slew rate limits alone in the 741 means you can't honestly ask it for more than a volt of output at full audio bandwidth. At 3 volts the slew rate distortion is so bad even these 75 year old ears can hear it. Even a TLO-72 or 74 can mop the floor with a 741, and output a +- 15 volt rail to rail signal doing it, but into the old 600 ohm std load. -- Cheers, Gene There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order. -Ed Howdershelt (Author) The only way for a reporter to look at a politician is down. -- H.L. Mencken ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Apr 29, 2010, at 12:48 AM, Gene Heskett wrote: Well, you started out complaining about a 741 model. I'd call that a very rare, obsolete part: I haven't actually seen one in a circuit in over 30 years. I guess it's still in textbooks (read Stephen J. Gould's rants about textbook authors' tendency to copy from previous textbooks sometime), but why would anyone use it in a new design? Very rare?! I see 741s everywhere. WTF? Sorry to bust the bubble, but he's right. The 741 is well over 40 years old, and its open loop first response pole, where the 6db per octave rolloff begins, is a measly 10 hertz. Today there are $1.00 opamps with a working gain of 20 when feedback is applied, with output slew rates of several thousand volts per second. Thats working bandwidth to several hundred megahertz at the sort of levels found in either a modern broadcast audio mixer, or a production video switcher, and either of those are driving 60 ohms for audio, or 75 for video. Slew rate limits alone in the 741 means you can't honestly ask it for more than a volt of output at full audio bandwidth. At 3 volts the slew rate distortion is so bad even these 75 year old ears can hear it. Even a TLO-72 or 74 can mop the floor with a 741, and output a +- 15 volt rail to rail signal doing it, but into the old 600 ohm std load. No bubbles to bust, I'm not particularly fond of the 741...yes there are definitely better opamps out there (I usually use OP07s as my general-purpose opamp) but that doesn't change the fact that I see 741s everywhere. They are far (VERY far) from rare. -Dave -- Dave McGuire Port Charlotte, FL ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
-Original Message- From: geda-user-boun...@moria.seul.org [mailto:geda-user-boun...@moria.seul.org] On Behalf Of Armin Faltl Sent: Saturday, April 24, 2010 8:52 PM To: gEDA user mailing list Subject: Re: gEDA-user: A little puzzled about the purpose of gschem I'm here only for a bit over a week, got a lot of help and try to contribute something. In my opinion, even if you were bashing gEDA or parts of it, this would be still your right, while probably no good place. What sounds like bashing in the ears of some contains constructive criticisim in the ears of others maybe. I didn't say anything about the patent thing yet. Well, I hold some patents, not in software. Studies show, that 80% of all technical knowledge openly available is described in patents only, no books no publications etc. A personal guess of mine is, that a similiar number of patents is expired already. Ignoring that knowledge because of a weird sense of political correctnes... There are even cases of patents that were acquired to make them open source ;-) There is hardly a better protection imaginable for an OS-implementation than an expired patent. Good point! ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Thu, Apr 22, 2010 at 11:09 PM, al davis ad...@freeelectron.net wrote: If you look at free/open-source software as a product to be consumed, like you consume commercial products, you will probably be disappointed. I disagree. While writing OSS has value in its own (as a method of gaining experience and skills by the author, and perhaps leaving some bits and pieces for someone to pick up later), primary motivation for doing it should be the same as in case of CSS - making a useful product. If that's not the case, then either OS methodology doesn't work or it is executed incorrectly. OSS has an interesting property - a critical mass of functionality. Once an OS program reaches the level at which it which it does something useful for the users, both user and developer base start growing exponentially. It takes a lot of time and work for the original author to reach this level, though. And in a field as competitive as EDA even that might not be enough. The bottom line is - there is nothing wrong with recommending Ltspice to users that need its functionality (especially that it is a very good tool and we can't match its functionality yet). Making the users aware of existence of Ngspice or Gnucap? Sure. Winning them over the features - not yet. Andrzej ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On 24/04/10 05:46, al davis wrote: On Friday 23 April 2010, Link wrote: Eh? Suppose you had instead said: === .. I suggest using Eagle through Darwine. In my personal experience, Eagle is a lot better than geda, and it is definitely an easier workflow. === Is this any different? No. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user I hadn't intended for anyone to interpret it that way, and I'm sorry if you interpreted that as bashing gEDA. Perhaps my choice of words was rather unfortunate. What I intended to is that one component (the simulator) of LTSpice tends to perform better _for me_ than gEDA's equivalents, in sheer terms of the simulation results being what I expect. I'm not sure if that is even a problem with gnucap/ngspice or if I'm simply doing something wrong myself, but I do know that I find LTSpice easier to use for simulation. That does not mean I dislike gEDA, or think it's bad, or anything of the sort - in fact, I find it to be absolutely brilliant for schematic capture and PCB design. That said, simulation in gEDA is only one of the many paths you can take with it, and perhaps because of that, along with the fact that circuit simulation is very very complicated mathematically, it is, for the time being, not very easy for the end user to get the expected simulation results quickly. As such, for an end user who may not have the time or skill to work on improving gEDA, and who already expressed confusion about how complicated the workflow is, it is possible that gEDA simply isn't the most suitable piece of software for that user yet (since gEDA is under very active development, that may change in the near future), and hence why I said, or at least intended to say, that if the workflow is an issue to that user, another piece of software - one that is, unfortunately, proprietary - may be better for that particular user. To summarise: -gEDA encompasses a lot more than simulation -As such, the workflow for simulation is a bit complicated -The simulators may or may not be as accurate as proprietary equivalents -As such, if workflow efficiency and simulation accuracy are a very big issue, then for someone who cannot improve gEDA directly, it is possible that for the time being, other software is better for said someone -The only software I know that has a workflow that is faster than gEDA's when it comes to simulation, and has a simulator at least as good as gEDA's equivalents, is unfortunately proprietary -As such, I recommended that software to a user who appeared to want a more efficient workflow for simulation I hope that clears things up. If not, I really don't know how to explain what I meant any better, so you will have to make do with the knowledge that I did not mean to sound like I was bashing gEDA. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Fri, 23 Apr 2010 23:46:41 -0400, al davis wrote: Suppose you had instead said: === .. I suggest using Eagle through Darwine. In my personal experience, Eagle is a lot better than geda, and it is definitely an easier workflow. === Is this any different? Yes it is. Unlike ltspice eagle is inferior to gschem in many relevant ways. Most notably it's GUI is a real PITA, in particular to newbies. Thus such an advice probably would not help the OP with his project. Unfortunately, the opposite is true for gschem/gnucap vs ltspice. If you suggest otherwise to the inexperienced newbie, he or she will find out the hard way and never come back. ---)kaimartin(--- -- Kai-Martin Knaak tel: +49-511-762-2895 Universität Hannover, Inst. für Quantenoptik fax: +49-511-762-2211 Welfengarten 1, 30167 Hannover http://www.iqo.uni-hannover.de GPG key:http://pgp.mit.edu:11371/pks/lookup?search=Knaak+kmkop=get ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Apr 24, 2010, at 10:30 AM, Kai-Martin Knaak wrote: Unfortunately, the opposite is true for gschem/gnucap vs ltspice Unfortunately, it takes more skill to drive a Jeep than it take to drive a tricycle. John Doty Noqsi Aerospace, Ltd. http://www.noqsi.com/ j...@noqsi.com ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
I don't think it is a matter of skill. I am an engineer / scientist who is interested in what *works*. I am paid to get a certain piece of work done (for the best possible design in the shortest amount of time), not spend time working around imperfections of certain pieces of software when better alternatives might exist. A smart person picks the best tool for the job (within the constraints), not pick up an ideology and then waste time working around imperfections in the current implementation of something consistent with that ideology. I don't want to get preachy here because there was a time when anything I used had to be open source (except for stuff prescribed for classes). I was merely looking for a clarification after I had formed certain negative first impressions. To me, it is obvious that pcb/geda is superior to eagle. But there is a gap between the schematic drawing program (gschem) and the circuit simulation that other competitors do not have. Since multiple circuit iterations usually occur during the simulation period of the design (long before it is laid out for a PCB), any extra time wasted in any one of these steps has a multiplier effect on the overall time spent. Professionally, that is unacceptable, regardless of my personal inclinations, or ideologies. I have come across MI-Sugar (which has been discontinued but free (not open source)). The author plans to release a successor to the program (Volta) in a couple of days, so I am going to check that out later. Of course, it does not have PCB layout, but for that, I can always use geda. I will like to thank all of you who informed me of various aspects of geda that I was not very conversant with. I might be back with further questions later about some other parts of geda that I find much better implemented from a usability standpoint than gschem. On Sat, Apr 24, 2010 at 9:34 AM, John Doty [1]...@noqsi.com wrote: On Apr 24, 2010, at 10:30 AM, Kai-Martin Knaak wrote: Unfortunately, the opposite is true for gschem/gnucap vs ltspice Unfortunately, it takes more skill to drive a Jeep than it take to drive a tricycle. John Doty Noqsi Aerospace, Ltd. [2]http://www.noqsi.com/ [3]...@noqsi.com ___ geda-user mailing list [4]geda-u...@moria.seul.org [5]http://www.seul.org/cgi-bin/mailman/listinfo/geda-user References 1. mailto:j...@noqsi.com 2. http://www.noqsi.com/ 3. mailto:j...@noqsi.com 4. mailto:geda-user@moria.seul.org 5. http://www.seul.org/cgi-bin/mailman/listinfo/geda-user ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Apr 24, 2010, at 2:28 PM, Madhusudan Singh wrote: I don't think it is a matter of skill. I am an engineer / scientist who is interested in what *works*. So am I. That's exactly why I find gEDA so powerful. I am paid to get a certain piece of work done (for the best possible design in the shortest amount of time), not spend time working around imperfections of certain pieces of software when better alternatives might exist. Failure to correspond to your prejudices is not imperfection. A smart person picks the best tool for the job (within the constraints), not pick up an ideology and then waste time working around imperfections in the current implementation of something consistent with that ideology. I don't want to get preachy here because there was a time when anything I used had to be open source (except for stuff prescribed for classes). I don't use gEDA because it is open source: I use it because it's an effective toolkit. Indeed, I sometimes use gschem to create symbolic circuit models for Mathematica, a very closed tool. Open is nice, but first I need *effective*. That's exactly what I get with gEDA. I was merely looking for a clarification after I had formed certain negative first impressions. To me, it is obvious that pcb/geda is superior to eagle. But there is a gap between the schematic drawing program (gschem) and the circuit simulation that other competitors do not have. A network of roads that can take you to an unlimited number of destinations is going to be more difficult to navigate than a single one-way street, at least until you're familiar with it. Since multiple circuit iterations usually occur during the simulation period of the design (long before it is laid out for a PCB), any extra time wasted in any one of these steps has a multiplier effect on the overall time spent. Professionally, that is unacceptable, regardless of my personal inclinations, or ideologies. Again, this doesn't happen when you have your flow set up in an efficient way, and gEDA is the very best EDA tool I've ever used at avoiding this problem. But you seem to *expect* low productivity, and you insist on using gEDA in a low productivity way. You complain of ideology, but your approach seems extremely ideological to me. I'm an astrophysicist: circuit design is a sideline. gEDA allows me to set up my processes for maximum automation, allowing me to do big design jobs as a part-timer. Much of this has to do with the way gEDA plays nicely with text tools, make, tex, and other automatable parts of the software universe. John Doty Noqsi Aerospace, Ltd. http://www.noqsi.com/ j...@noqsi.com ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Saturday 24 April 2010, Link wrote: I hadn't intended for anyone to interpret it that way, and I'm sorry if you interpreted that as bashing gEDA. Perhaps my choice of words was rather unfortunate. Apology accepted. What I intended to is that one component (the simulator) of LTSpice tends to perform better _for me_ than gEDA's equivalents, in sheer terms of the simulation results being what I expect. I'm not sure if that is even a problem with gnucap/ngspice or if I'm simply doing something wrong myself, but I do know that I find LTSpice easier to use for simulation. That does not mean I dislike gEDA, or think it's bad, or anything of the sort - in fact, I find it to be absolutely brilliant for schematic capture and PCB design. There is a real problem with the way gnetlist works. (contrary to what some others here say). I have known this for years. Often people have trouble with it. I don't know what to say. It seems I always need to hack the netlist. I have tried to recruit help on this, specifically making gschem and pcb plugins for the gnucap translator system. No takers. Maybe when I get my other pile of work out of the way I will do it myself, for both geda and kicad. Then gspiceui doesn't help. I don't like that style anyway. For a beginner, combined with how gnetlist works, I don't know what to do. In this environment, it's not gnucap or ngspice that is the trouble spot. It's gnetlist, documentation, and communication between tools. So the situation here is that people don't see the capability that ngspice and gnucap have because of problems elsewhere. The other problem people run into is that nobody here has collected the hundreds (thousands?) of models (of all kinds) that come from all over. A commercial organization can pay a junior person full time to maintain the collection. That's what it takes. Not in a commercial environment, this kind of thing has to be done by the community, a shared effort. But really google for it, and check to see if it makes sense is the correct answer. A lot of those models don't make sense for the particular application people are asking about. The big collection that LT and P spice have, that is still incomplete because it is impossible to be truly complete, lulls users into a false confidence. As far as simulation results go .. If it gives you trouble, please report it. I'm well aware of the Spice3f5 false convergence issue, and that it still exists in NGspice. I'm well aware of the NGspice step control bugs, where an attempt to fix 3f5 problems really made it worse. I am not convinced that LTspice is any better in these issues than NGspice. As far as I know, Gnucap doesn't have these problems. Convergence and step control are never perfect. It seems to work for me, but if it doesn't for you, the only way it can get better is if you let me know about the problem, and send a test case that demonstrates it. The benchmarks I have tend to show that Gnucap usually outperforms NGspice on difficult circuits, and that LTspice usually performed about the same as NGspice. NGspice is often faster than Gnucap on small circuits, where both are fast enough that it doesn't really matter. The last time I made any of these comparisons was a few years ago, so some things might have changed. Gnucap has improved, perhaps LTspice has improved too. NGspice hasn't really changed in this regard. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Apr 24, 2010, at 5:42 PM, al davis wrote: On Saturday 24 April 2010, Link wrote: I hadn't intended for anyone to interpret it that way, and I'm sorry if you interpreted that as bashing gEDA. Perhaps my choice of words was rather unfortunate. Apology accepted. What I intended to is that one component (the simulator) of LTSpice tends to perform better _for me_ than gEDA's equivalents, in sheer terms of the simulation results being what I expect. I'm not sure if that is even a problem with gnucap/ngspice or if I'm simply doing something wrong myself, but I do know that I find LTSpice easier to use for simulation. That does not mean I dislike gEDA, or think it's bad, or anything of the sort - in fact, I find it to be absolutely brilliant for schematic capture and PCB design. There is a real problem with the way gnetlist works. (contrary to what some others here say). I have known this for years. Often people have trouble with it. I don't know what to say. It seems I always need to hack the netlist. In what way? Which gnetlist back end are you using? These things can be fixed, you know. Guile's easy if you're not phobic about parentheses ;-) I have tried to recruit help on this, specifically making gschem and pcb plugins for the gnucap translator system. No takers. You're fighting against the power of the toolkit instead of exploiting it, I think. Maybe when I get my other pile of work out of the way I will do it myself, for both geda and kicad. Then gspiceui doesn't help. I don't like that style anyway. For a beginner, combined with how gnetlist works, I don't know what to do. In this environment, it's not gnucap or ngspice that is the trouble spot. It's gnetlist, documentation, and communication between tools. So the situation here is that people don't see the capability that ngspice and gnucap have because of problems elsewhere. The other problem people run into is that nobody here has collected the hundreds (thousands?) of models (of all kinds) that come from all over. A commercial organization can pay a junior person full time to maintain the collection. And they can pay the model owners for redistribution licenses. That's what it takes. There are also legal problems. My personal model library contains models that are free as in beer, but not as in speech. Some cannot be legally redistributed, especially together with GPL software. You have to get them from their owners. Not in a commercial environment, this kind of thing has to be done by the community, a shared effort. But really google for it, and check to see if it makes sense is the correct answer. A lot of those models don't make sense for the particular application people are asking about. Indeed. John Doty Noqsi Aerospace, Ltd. http://www.noqsi.com/ j...@noqsi.com ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
I'm here only for a bit over a week, got a lot of help and try to contribute something. In my opinion, even if you were bashing gEDA or parts of it, this would be still your right, while probably no good place. What sounds like bashing in the ears of some contains constructive criticisim in the ears of others maybe. I didn't say anything about the patent thing yet. Well, I hold some patents, not in software. Studies show, that 80% of all technical knowledge openly available is described in patents only, no books no publications etc. A personal guess of mine is, that a similiar number of patents is expired already. Ignoring that knowledge because of a weird sense of political correctnes... There are even cases of patents that were acquired to make them open source ;-) There is hardly a better protection imaginable for an OS-implementation than an expired patent. I hope that clears things up. If not, I really don't know how to explain what I meant any better, so you will have to make do with the knowledge that I did not mean to sound like I was bashing gEDA. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Sat, Apr 24, 2010 at 2:17 PM, John Doty [1]...@noqsi.com wrote: On Apr 24, 2010, at 2:28 PM, Madhusudan Singh wrote: I don't think it is a matter of skill. I am an engineer / scientist who is interested in what *works*. So am I. That's exactly why I find gEDA so powerful. I am paid to get a certain piece of work done (for the best possible design in the shortest amount of time), not spend time working around imperfections of certain pieces of software when better alternatives might exist. Failure to correspond to your prejudices is not imperfection. Needing an extra 20 minutes after wiring the net, to populate spice models for each gschem schematic (instead of having a set of default libraries that do that for common circuit elements) for each circuit, compared to spending 0 extra minutes on something like LTSpice or PSpice is not prejudice. It is 20 minutes of wasted time. Of course, I have a decided prejudice against wasted time of that sort. So, very prejudicially, I view it as an imperfection. Since multiple circuit iterations usually occur during the simulation period of the design (long before it is laid out for a PCB), any extra time wasted in any one of these steps has a multiplier effect on the overall time spent. Professionally, that is unacceptable, regardless of my personal inclinations, or ideologies. Again, this doesn't happen when you have your flow set up in an efficient way, and gEDA is the very best EDA tool I've ever used at avoiding this problem. But you seem to *expect* low productivity, and you insist on using gEDA in a low productivity way. You complain of ideology, but your approach seems extremely ideological to me. You do have an interesting definition of productivity then. But no matter. I'm an astrophysicist: circuit design is a sideline. gEDA allows me to set up my processes for maximum automation, allowing me to do big design jobs as a part-timer. Much of this has to do with the way gEDA plays nicely with text tools, make, tex, and other automatable parts of the software universe. I am orders of magnitude off from your work (I started in positional astronomy, and changed fields to condensed matter, and then finally nanoelectronics). I think geda is amazingly good, but gschem is a weak point. YMMV. References 1. mailto:j...@noqsi.com ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Apr 24, 2010, at 7:16 PM, Madhusudan Singh wrote: Failure to correspond to your prejudices is not imperfection. Needing an extra 20 minutes after wiring the net, to populate spice models for each gschem schematic (instead of having a set of default libraries that do that for common circuit elements) for each circuit, I really don't think you understand how the process works. Can you post a schematic? All you should be doing is attaching model-name= and perhaps file= (although I prefer to include a library once) to active components. Not so hard. What you consider common circuit elements are undoubtedly different from what I commonly use. That's how it goes. You have to build your own library, just like I had to when I was using Pspice back in the '90s. compared to spending 0 extra minutes on something like LTSpice or PSpice is not prejudice. It is 20 minutes of wasted time. Of course, I have a decided prejudice against wasted time of that sort. So, very prejudicially, I view it as an imperfection. The real time wasters aren't the setup, but the the repeated manual operations of GUI tools. Since multiple circuit iterations usually occur during the simulation period of the design (long before it is laid out for a PCB), any extra time wasted in any one of these steps has a multiplier effect on the overall time spent. Professionally, that is unacceptable, regardless of my personal inclinations, or ideologies. Again, this doesn't happen when you have your flow set up in an efficient way, and gEDA is the very best EDA tool I've ever used at avoiding this problem. But you seem to *expect* low productivity, and you insist on using gEDA in a low productivity way. You complain of ideology, but your approach seems extremely ideological to me. You do have an interesting definition of productivity then. But no matter. Given that I've designed 6000 transistor VLSI chips and 1000 component circuit boards with gschem, I think I understand its productivity. You have to use the power of the toolkit, not struggle against it. John Doty Noqsi Aerospace, Ltd. http://www.noqsi.com/ j...@noqsi.com ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On 22/04/10 16:09, al davis wrote: I find it somewhat ironic that penguindevelopment.org doesn't seem to understand the concept. Eh? I understand it perfectly well. The thing is, though, that sometimes it is simply not practical to use FLOSS when you need a feature right away that simply isn't there. Sometimes people just lack the skill and/or time to contribute. Free and open source software is beautiful, but that doesn't mean it always has everything to offer that is needed for every single user, at any given moment. In this particular case, I was simply replying to someone who appeared to want some features not yet in gEDA. As such, I just don't understand why you blatantly assume I don't understand the concept of FLOSS, or why you assumed I was bashing anything - because I didn't. All I ever said was in this particular case, another workflow - unfortunately one that isn't open-source - might be better for this user. That said, gEDA is a beautiful piece of software. It has a lot of features, and is very powerful - but not quite as powerful as some other programs, that unfortunately aren't open-source. Trust me, if I had the time and skill to implement those features in gEDA, I would - but I don't. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Friday 23 April 2010, Link wrote: Eh? Suppose you had instead said: === .. I suggest using Eagle through Darwine. In my personal experience, Eagle is a lot better than geda, and it is definitely an easier workflow. === Is this any different? No. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
hey im new to using the gEDA suit as well. but i suggest you look at the following links so that you better understand the gEDA tools and their limitations. gEDA tools docs http://geda.seul.org/wiki/geda:documentation tutorial using gschem: http://geda.seul.org/wiki/geda:gsch2pcb_tutorial gEDA gschem User Guide http://geda.seul.org/wiki/geda:gschem_ug hope that helps. David From: geda-user-boun...@moria.seul.org [geda-user-boun...@moria.seul.org] On Behalf Of Madhusudan Singh [singh.madhusu...@gmail.com] Sent: Thursday, April 22, 2010 1:26 AM To: geda-u...@oria.seul.org Subject: gEDA-user: A little puzzled about the purpose of gschem Hello, I am not new (though a tad rusty) to spice, or the usual design process. Years ago, I went through an analog circuit design, followed by a VLSI design class that involved the use of H-Spice, Mentor Graphics and Cadence software, basically Design Architect, (Modelsim for digital design), Accusim, IC Station, DRC, LVS workflow, with the (IIRC) AMI05 library. I am finding myself in need of doing some circuit design for a lab application, and without access to the aforementioned software and having developed a slight preference for the faster GUI based work (as opposed to using MacSpice - I am on Mac OSX where geda, pcb, etc. are all installed using MacPorts, and seem to launch ok), I decided to give geda a spin. The overall workflow looks superficially similar to the one I outlined above. So, I fire up gschem and decide to test it with a rudimentary inverting op amp circuit using a 741. I wire the net, and then discover I need to use command line gnetlist to generate the actual spice netlist. No biggie, years of Sun and Linux experience (and importantly, zero windows experience) make this a piece of cake. gschem editor experience is remarkably like DA. But, I get a truckload of errors. I start researching and find this gem: http://www.brorson.com/gEDA/SPICE/x150.html Basically, I need to painfully enter all the parameters for a 741 ! There is even a file parameter where I can presumably enter the filename containing the spice model by hand. At that point I stopped to take stock of the whole thing. Correct me if I am wrong, but isn't the entire point of having a GUI entry to ease and more importantly, speed, the development process ? So, precisely in which way is using gschem more efficient than typing in a spice script if I have to painfully pointy-and-clicky every damn single attribute into this ? Some might say that after defining a symbol, I can copy and paste it to create more complicated circuits, but that is what a subckt definition is for. I guess I am asking - what purpose does gschem serve (other than to create pretty pictures, and being a humongous waste of time otherwise since its basically asking you to enter the entire spice script, albeit in disparate pretty boxes) ? Thanks. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On 22/04/10 07:26, Madhusudan Singh wrote: Hello, I am not new (though a tad rusty) to spice, or the usual design process. Years ago, I went through an analog circuit design, followed by a VLSI design class that involved the use of H-Spice, Mentor Graphics and Cadence software, basically Design Architect, (Modelsim for digital design), Accusim, IC Station, DRC, LVS workflow, with the (IIRC) AMI05 library. I am finding myself in need of doing some circuit design for a lab application, and without access to the aforementioned software and having developed a slight preference for the faster GUI based work (as opposed to using MacSpice - I am on Mac OSX where geda, pcb, etc. are all installed using MacPorts, and seem to launch ok), I decided to give geda a spin. The overall workflow looks superficially similar to the one I outlined above. So, I fire up gschem and decide to test it with a rudimentary inverting op amp circuit using a 741. I wire the net, and then discover I need to use command line gnetlist to generate the actual spice netlist. No biggie, years of Sun and Linux experience (and importantly, zero windows experience) make this a piece of cake. gschem editor experience is remarkably like DA. But, I get a truckload of errors. I start researching and find this gem: [1]http://www.brorson.com/gEDA/SPICE/x150.html Basically, I need to painfully enter all the parameters for a 741 ! There is even a file parameter where I can presumably enter the filename containing the spice model by hand. At that point I stopped to take stock of the whole thing. Correct me if I am wrong, but isn't the entire point of having a GUI entry to ease and more importantly, speed, the development process ? So, precisely in which way is using gschem more efficient than typing in a spice script if I have to painfully pointy-and-clicky every damn single attribute into this ? Some might say that after defining a symbol, I can copy and paste it to create more complicated circuits, but that is what a subckt definition is for. I guess I am asking - what purpose does gschem serve (other than to create pretty pictures, and being a humongous waste of time otherwise since its basically asking you to enter the entire spice script, albeit in disparate pretty boxes) ? Thanks. References 1. http://www.brorson.com/gEDA/SPICE/x150.html ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user gschem isn't a SPICE frontend, and in fact it is only tangentially related to SPICE. As such, it doesn't ship with any SPICE models, and as a result, including default model parameters would make no sense (since any spice models that may or may not be available on the system would probably have a different name than the default anyway). That said, you only need to enter the model names/paths for your .subckt models. If you have your schematic ready, you can also use gattrib to edit the parameters of all components at once in a tabular fashion. The advantage gschem gives over manual writing of SPICE files is that you have a visual representation of your eventual netlist, and an integrated circuit symbol with the pin names included is much more obvious than X1 followed by some numbers and an obscure name. However, if you want a quick, graphical SPICE, I suggest using LTSpice through Darwine. In my personal experience, LTSpice's simulator is a lot better than ngspice/gnucap, and it is definitely an easier workflow than gschem-gattrib-gnetlist-ngspice if you're only interested in simulation. Peter ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Apr 21, 2010, at 11:26 PM, Madhusudan Singh wrote: Basically, I need to painfully enter all the parameters for a 741 ! No, basically you need to find some manufacturer's model file. gEDA can't include those for legal reasons, but even the expensive commercial packages that include models only have a subset of what you need for a real design. There is even a file parameter where I can presumably enter the filename containing the spice model by hand. Use that once you have a model file, yes. Often I just use the model-name attribute to specify a subcircuit name and then include a file of subcircuits with the spice-include-1 symbol. At that point I stopped to take stock of the whole thing. Correct me if I am wrong, but isn't the entire point of having a GUI entry to ease and more importantly, speed, the development process ? Fundamentally, the purpose of GUI is graphical communication. But for non-graphical processes, GUI gets in the way. It therefore scales poorly to big jobs: they turn into manual button-pushing exercises, when automation is needed. gEDA is a flexible toolkit that scales very well. So, precisely in which way is using gschem more efficient than typing in a spice script if I have to painfully pointy-and-clicky every damn single attribute into this ? It creates a drawing in a format that allows gnetlist to generate the connections from the graphics. Some might say that after defining a symbol, I can copy and paste it to create more complicated circuits, but that is what a subckt definition is for. One thing gEDA lets you do easily is to build a library of custom symbol files that precisely match the needs of your projects and processes. And a lot of us share such files at gedasymbols.org. I guess I am asking - what purpose does gschem serve It's good for schematic capture for just about any purpose at all. gnetlist can export a wide variety of printed circuit board netlists, SPICE, Verilog, bills of materials, and even Mathematica code for symbolic circuit analysis. (other than to create pretty pictures, and being a humongous waste of time otherwise since its basically asking you to enter the entire spice script, albeit in disparate pretty boxes) ? But it doesn't ask you to do that. Go back and read Stuart's whole document. The power of gEDA? Well, last week a question came up about a mixed-signal VLSI design I put together using gEDA a couple of years ago. So I went to the simulation directory, typed make PreamplifierTest. The Makefile rules figured out which subcircuit netlists needed to be generated, generated them with gnetlist, and then put me into ngspice with the simulation loaded. All I had to do was tran and plot to get the specific output I needed. No elaborate GUI procedures to reconstruct from memory, just three simple commands. gEDA is a flexible kit of tools that plays well with other tools (make, tex, awk, layout tools, ...). That makes it good for a wide variety of jobs. For big jobs it's far more productive than the integrated point-and-click-all-day-long tools. John Doty Noqsi Aerospace, Ltd. http://www.noqsi.com/ j...@noqsi.com ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Thursday 22 April 2010, Link wrote: However, if you want a quick, graphical SPICE, I suggest using LTSpice through Darwine. In my personal experience, LTSpice's simulator is a lot better than ngspice/gnucap, and it is definitely an easier workflow than gschem-gattrib-gnetlist-ngspice if you're only interested in simulation. One reason commercial software (including zero-dollar commercial software like LTspice and the light version of Eagle) may be better in some ways is that some people choose to bash rather than to enter a dialog that could be helpful. If you look at free/open-source software as a product to be consumed, like you consume commercial products, you will probably be disappointed. If you are looking for a handout, sorry, it doesn't work that way. On the other hand, if you appreciate the openness, and want something more organic, free/open-source software opens up possibilities that commercial software doesn't come near. If you want to learn by getting involved with a project, free/open-source software offers big opportunities to learn and connect that you can't get anywhere else. These opportunities are offered to EVERYONE, not just A students. I find it somewhat ironic that penguindevelopment.org doesn't seem to understand the concept. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
Your real problem seems to be that you don't have to any opamp models. You can either: 1) Get the manufacturer's model, which may have to be modified to work in your simulator 2) Get spicelib from http://github.com/werner2101/spicelib . It will download a large number of models from the vendors and fix them to work in ngspice and gnucap for you. Chances are your opamp will be among them. You may also want to look at gspiceui. It doesn't include models, but it does have a nice gui for configuration your simulation parameters. -Alan On Thu, Apr 22, 2010 at 8:09 AM, al davis ad...@freeelectron.net wrote: On Thursday 22 April 2010, Link wrote: However, if you want a quick, graphical SPICE, I suggest using LTSpice through Darwine. In my personal experience, LTSpice's simulator is a lot better than ngspice/gnucap, and it is definitely an easier workflow than gschem-gattrib-gnetlist-ngspice if you're only interested in simulation. One reason commercial software (including zero-dollar commercial software like LTspice and the light version of Eagle) may be better in some ways is that some people choose to bash rather than to enter a dialog that could be helpful. If you look at free/open-source software as a product to be consumed, like you consume commercial products, you will probably be disappointed. If you are looking for a handout, sorry, it doesn't work that way. On the other hand, if you appreciate the openness, and want something more organic, free/open-source software opens up possibilities that commercial software doesn't come near. If you want to learn by getting involved with a project, free/open-source software offers big opportunities to learn and connect that you can't get anywhere else. These opportunities are offered to EVERYONE, not just A students. I find it somewhat ironic that penguindevelopment.org doesn't seem to understand the concept. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
Thanks to everyone who responded. Just so that everyone is clear, I understand and appreciate the amount of work that has likely gone into geda. I have authored two smaller, unrelated LGPL projects myself and would never mock anyone for doing this. A couple of people have mentioned that I need to enter a library. My questions: Do these libraries bind the attributes to the symbols (so that I do not have to do any post-gschem drawing and pre-gnetlist work) ? As to the respondent who said that gschem is useful because it creates the net that gnetlist can use to generate the netlist, I am sorry to say that you are missing the bigger picture in the workflow. The way my initial experience was - I found that I would have to enter portions of that spice netlist in some scattered boxes in gschem, then use gnetlist to presumably do some topological analysis and write out the actual node numbers in the spice netlist. That is where there is a disconnect. There is no way that that is a more efficient use of anyone's time than simply drawing a circuit by hand, assigning node numbers and typing it all in in one shot. Now, if I could use a library that came with properly defined symbols (instead of just empty pretty pictures that they are right now), I could see the utility of doing this. Without that, its a waste of time. And to the respondent who said that GUIs are not necessarily faster than typing it by hand, I would have to disagree. I am hazarding a guess that you have not used Design Architect (and yes, I have timed the two approaches in the past - the DA bit was much much faster for even a moderately complicated circuit). The difference was - that beyond defining input and output nodes, I did not have to do any post-drawing pointy-clicky. All I now need are good libraries and a proper tutorial that shows how they can be used in gschem properly (see above). Someone linked a source - are there others ? Most vendors provide text spice libraries. How can they be converted into a form that gschem can understand ? ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Apr 22, 2010, at 11:11 AM, Madhusudan Singh wrote: Now, if I could use a library that came with properly defined symbols (instead of just empty pretty pictures that they are right now), I could see the utility of doing this. A common complaint. But when you look deeper you find that nearly everyone who makes this complaint has a different idea of what a properly defined symbol might be. There are so many ways to use gEDA, and millions of electronic parts on the market. A library of a trillion symbols would not suffice. Without that, its a waste of time. The big time wasters are tools that force your project away from the flow it needs. gEDA doesn't do that. John Doty Noqsi Aerospace, Ltd. http://www.noqsi.com/ j...@noqsi.com ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Apr 22, 2010, at 11:11 AM, Madhusudan Singh wrote: As to the respondent who said that gschem is useful because it creates the net that gnetlist can use to generate the netlist, I am sorry to say that you are missing the bigger picture in the workflow. The way my initial experience was - I found that I would have to enter portions of that spice netlist in some scattered boxes in gschem, then use gnetlist to presumably do some topological analysis and write out the actual node numbers in the spice netlist. That is where there is a disconnect. There is no way that that is a more efficient use of anyone's time than simply drawing a circuit by hand, assigning node numbers and typing it all in in one shot. Well, all I can say is that I certainly can't manually assign node numbers faster than gnetlist does for any circuit larger than maybe three components. But I design VLSI with thousands of transistors using gEDA. The only portions of that spice netlist in some scattered boxes you find in my schematics are things like .INCLUDE, subcircuit names, and the occasional simulator command. If you're putting in more than that, you're not using the tool effectively. John Doty Noqsi Aerospace, Ltd. http://www.noqsi.com/ j...@noqsi.com ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Apr 22, 2010, at 11:11 AM, Madhusudan Singh wrote: Do these libraries bind the attributes to the symbols (so that I do not have to do any post-gschem drawing and pre-gnetlist work) ? No. gnetlist cannot read your mind. It doesn't know which model you intend to use for your opamp, for example, and the symbol author may not have set the pinseq attributes to match the model, unknown to them, that you're using. Remember that gEDA is multi-purpose, not designed for your specific needs, which are unknown to the designers anyway. But you don't have to do any post-gschem drawing. What did you mean by that? John Doty Noqsi Aerospace, Ltd. http://www.noqsi.com/ j...@noqsi.com ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Apr 22, 2010, at 11:11 AM, Madhusudan Singh wrote: And to the respondent who said that GUIs are not necessarily faster than typing it by hand, I would have to disagree. I am hazarding a guess that you have not used Design Architect (and yes, I have timed the two approaches in the past - the DA bit was much much faster for even a moderately complicated circuit). The difference was - that beyond defining input and output nodes, I did not have to do any post-drawing pointy-clicky. I would guess you've never tackled a big project with multiple external requirements, combining hardware, software, simulations and documentation. All I now need are good libraries and a proper tutorial that shows how they can be used in gschem properly (see above). Someone linked a source - are there others ? Most vendors provide text spice libraries. How can they be converted into a form that gschem can understand ? Gschem doesn't understand SPICE libraries at all: that's not its job. If you use gnetlist -g spice-sdb it peeks at some of the files to get a clue as to what they are (and maybe that's a misfeature). Whichever SPICE you're using interprets the library format. John Doty Noqsi Aerospace, Ltd. http://www.noqsi.com/ j...@noqsi.com ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Apr 22, 2010, at 11:11 AM, Madhusudan Singh wrote: And to the respondent who said that GUIs are not necessarily faster than typing it by hand, Type by hand? No! Write build rules once, use them many times. Don't click through the procedure repeatedly... John Doty Noqsi Aerospace, Ltd. http://www.noqsi.com/ j...@noqsi.com ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
I think most people end up building a small library of gschem symbols that they use. If they work with Spice a lot, the symbols will include the references to the necessary spice models. Once they have that work of creating models complete, then it's just a matter of arranging everything into a circuit, cut-and-paste, etc. The next time you need to simulate a circuit, you'll probably be able to reuse a large number of your symbols and you'll be able to get going a lot quicker. You should be able to do essentially all of your editing in gschem, then just run gnetlist and the simulator. No editing after the gschem stage. __ From: Madhusudan Singh singh.madhusu...@gmail.com To: gEDA user mailing list geda-user@moria.seul.org Sent: Thu, April 22, 2010 1:11:11 PM Subject: Re: gEDA-user: A little puzzled about the purpose of gschem Thanks to everyone who responded. Just so that everyone is clear, I understand and appreciate the amount of work that has likely gone into geda. I have authored two smaller, unrelated LGPL projects myself and would never mock anyone for doing this. A couple of people have mentioned that I need to enter a library. My questions: Do these libraries bind the attributes to the symbols (so that I do not have to do any post-gschem drawing and pre-gnetlist work) ? As to the respondent who said that gschem is useful because it creates the net that gnetlist can use to generate the netlist, I am sorry to say that you are missing the bigger picture in the workflow. The way my initial experience was - I found that I would have to enter portions of that spice netlist in some scattered boxes in gschem, then use gnetlist to presumably do some topological analysis and write out the actual node numbers in the spice netlist. That is where there is a disconnect. There is no way that that is a more efficient use of anyone's time than simply drawing a circuit by hand, assigning node numbers and typing it all in in one shot. Now, if I could use a library that came with properly defined symbols (instead of just empty pretty pictures that they are right now), I could see the utility of doing this. Without that, its a waste of time. And to the respondent who said that GUIs are not necessarily faster than typing it by hand, I would have to disagree. I am hazarding a guess that you have not used Design Architect (and yes, I have timed the two approaches in the past - the DA bit was much much faster for even a moderately complicated circuit). The difference was - that beyond defining input and output nodes, I did not have to do any post-drawing pointy-clicky. All I now need are good libraries and a proper tutorial that shows how they can be used in gschem properly (see above). Someone linked a source - are there others ? Most vendors provide text spice libraries. How can they be converted into a form that gschem can understand ? ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
That was really uncalled for. I was talking about symbol definitions, and not gnetlist. On Thu, Apr 22, 2010 at 10:48 AM, John Doty [1]...@noqsi.com wrote: On Apr 22, 2010, at 11:11 AM, Madhusudan Singh wrote: Do these libraries bind the attributes to the symbols (so that I do not have to do any post-gschem drawing and pre-gnetlist work) ? No. gnetlist cannot read your mind. It doesn't know which model you intend to use for your opamp, for example, and the symbol author may not have set the pinseq attributes to match the model, unknown to them, that you're using. Remember that gEDA is multi-purpose, not designed for your specific needs, which are unknown to the designers anyway. But you don't have to do any post-gschem drawing. What did you mean by that? John Doty Noqsi Aerospace, Ltd. [2]http://www.noqsi.com/ [3]...@noqsi.com ___ geda-user mailing list [4]geda-u...@moria.seul.org [5]http://www.seul.org/cgi-bin/mailman/listinfo/geda-user References 1. mailto:j...@noqsi.com 2. http://www.noqsi.com/ 3. mailto:j...@noqsi.com 4. mailto:geda-user@moria.seul.org 5. http://www.seul.org/cgi-bin/mailman/listinfo/geda-user ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Apr 22, 2010, at 1:44 PM, Madhusudan Singh wrote: That was really uncalled for. I'm sorry you feel that way. I was talking about symbol definitions, and not gnetlist. They are deeply connected. The symbol definition depends on the downstream flow, and gnetlist is a major agent of that flow. There is no correct symbol definition that is independent of the way you are using the symbol. The gnetlist back end is responsible for grabbing the attributes from the schematic and either interpreting them or passing them along to the next stage, as needed. Which back end you choose determines which attributes matter, and to some extent how they will be interpreted. While the relatively light symbol definitions in the standard library are suitable for a variety of flows, they usually lack the specialized attributes (like model-name) needed for a specialized flow (like ngspice via the spice-sdb gnetlist back end). Please try to understand that gEDA isn't an integrated tool that forces you into a particular flow. It's a versatile toolkit. That perhaps puts a burden on you when you're starting out, but is richly rewarding once you have libraries and processes customized to your needs. John Doty Noqsi Aerospace, Ltd. http://www.noqsi.com/ j...@noqsi.com ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
On Apr 22, 2010, at 12:44 PM, Madhusudan Singh wrote: That was really uncalled for. Don't take it too hard; Most things that he posts to this list are uncalled for. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
gEDA-user: A little puzzled about the purpose of gschem
Hello, I am not new (though a tad rusty) to spice, or the usual design process. Years ago, I went through an analog circuit design, followed by a VLSI design class that involved the use of H-Spice, Mentor Graphics and Cadence software, basically Design Architect, (Modelsim for digital design), Accusim, IC Station, DRC, LVS workflow, with the (IIRC) AMI05 library. I am finding myself in need of doing some circuit design for a lab application, and without access to the aforementioned software and having developed a slight preference for the faster GUI based work (as opposed to using MacSpice - I am on Mac OSX where geda, pcb, etc. are all installed using MacPorts, and seem to launch ok), I decided to give geda a spin. The overall workflow looks superficially similar to the one I outlined above. So, I fire up gschem and decide to test it with a rudimentary inverting op amp circuit using a 741. I wire the net, and then discover I need to use command line gnetlist to generate the actual spice netlist. No biggie, years of Sun and Linux experience (and importantly, zero windows experience) make this a piece of cake. gschem editor experience is remarkably like DA. But, I get a truckload of errors. I start researching and find this gem: [1]http://www.brorson.com/gEDA/SPICE/x150.html Basically, I need to painfully enter all the parameters for a 741 ! There is even a file parameter where I can presumably enter the filename containing the spice model by hand. At that point I stopped to take stock of the whole thing. Correct me if I am wrong, but isn't the entire point of having a GUI entry to ease and more importantly, speed, the development process ? So, precisely in which way is using gschem more efficient than typing in a spice script if I have to painfully pointy-and-clicky every damn single attribute into this ? Some might say that after defining a symbol, I can copy and paste it to create more complicated circuits, but that is what a subckt definition is for. I guess I am asking - what purpose does gschem serve (other than to create pretty pictures, and being a humongous waste of time otherwise since its basically asking you to enter the entire spice script, albeit in disparate pretty boxes) ? Thanks. References 1. http://www.brorson.com/gEDA/SPICE/x150.html ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: A little puzzled about the purpose of gschem
I think you use it for, you know, schematic entry when you're actually like, you know, designing a PCB. -tc On Thu, Apr 22, 2010 at 2:26 PM, Madhusudan Singh singh.madhusu...@gmail.com wrote: Hello, I am not new (though a tad rusty) to spice, or the usual design process. Years ago, I went through an analog circuit design, followed by a VLSI design class that involved the use of H-Spice, Mentor Graphics and Cadence software, basically Design Architect, (Modelsim for digital design), Accusim, IC Station, DRC, LVS workflow, with the (IIRC) AMI05 library. I am finding myself in need of doing some circuit design for a lab application, and without access to the aforementioned software and having developed a slight preference for the faster GUI based work (as opposed to using MacSpice - I am on Mac OSX where geda, pcb, etc. are all installed using MacPorts, and seem to launch ok), I decided to give geda a spin. The overall workflow looks superficially similar to the one I outlined above. So, I fire up gschem and decide to test it with a rudimentary inverting op amp circuit using a 741. I wire the net, and then discover I need to use command line gnetlist to generate the actual spice netlist. No biggie, years of Sun and Linux experience (and importantly, zero windows experience) make this a piece of cake. gschem editor experience is remarkably like DA. But, I get a truckload of errors. I start researching and find this gem: [1]http://www.brorson.com/gEDA/SPICE/x150.html Basically, I need to painfully enter all the parameters for a 741 ! There is even a file parameter where I can presumably enter the filename containing the spice model by hand. At that point I stopped to take stock of the whole thing. Correct me if I am wrong, but isn't the entire point of having a GUI entry to ease and more importantly, speed, the development process ? So, precisely in which way is using gschem more efficient than typing in a spice script if I have to painfully pointy-and-clicky every damn single attribute into this ? Some might say that after defining a symbol, I can copy and paste it to create more complicated circuits, but that is what a subckt definition is for. I guess I am asking - what purpose does gschem serve (other than to create pretty pictures, and being a humongous waste of time otherwise since its basically asking you to enter the entire spice script, albeit in disparate pretty boxes) ? Thanks. References 1. http://www.brorson.com/gEDA/SPICE/x150.html ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
