On Sunday 13 March 2005 15:54, Stuart Brorson wrote: >Hi Guys -- > >Welcome to gEDA! > >> >> Also, in grepping for the chip building blocks I'd need, none >> >> of the 3 main chips '82c55', 'L298' or 'L297' I need seem to be >> >> present. >> > >> >That's simply because none of the existing gEDA users have had a >> > need for these symbols. What I do in this case if find a symbol >> > that is close to the one I need and modify it. >> >> Possible, but the 8255 family is almost a cpu in it own right, so >> I doubt there is anything useable other than its 40 pin 600 mill >> dip packageing. And 24 of those 40 pins can input, or output, >> depending on how its mode register is programmed. One would have >> to write 16 variations of it and use the one corresponding to the >> mode byte. That, as they say, makes the cheese a bit more binding. > >First, I think you need to distinguish between the device's symbol >and its footprint. The symbol is the graphic object you place on > the schematic using gschem. The footprint is the graphic object > you place on the PC board using PCB. > Point taken. Not fully understood, but taken.
>There are plenty of parts with no symbols in gEDA. This is because >everybody just makes their own symbol for their specific job, and >nobody shares the symbols after that. It's just human nature -- >sharing software is fun, sharing symbols isn't. . . . go figure. >Anyway, you will probably need to make your own symbol. > >As for the footprint, you will need to run PCB to see if it exists. >If it's a standard symbol, it may exist. If it's not, then you'll >need to make it. There is a link to a doc talking about building > PCB symbols on this webpage: > >http://www.brorson.com/gEDA/ I'll be right there... And I got the tutorial, thanks. >Also, John Luciani has build a large number of PCB footprints; he > put them on the web for free download here: > >http://www.luciani.org/geda/pcb-footprint-list.html I'll check that too. Well, was going to, but its not found I do get a dir full of... found it, missing '/pcb' in the string above :) I dl'd pcb-symbols-jcl.gz, which says its the whole thing in one sock.gz. >> How is ngspice at simulating analogue circuitry thats supposed to >> be running in pwm mode? > >Probably slow -- it doesn't have the concept of event-driven >simulation, which is very useful for simulating pwm-mode circuits. >Try GnuCap instead. Or download LTSpice from the Linear Tech > website. It is Windows native (yuck!), but you can also run it > under wine. Humm, I'd forgotten that, seems I ran into that the last time I ran spice-5.something or druther on my amiga a decade back. Wine? Windows Spit... Partially because I've never found any windows proggy that wine could run here, too many miss-set options in the startups probably, but I've no real patience for windows stuff anyway, I came up thru the ranks of machine coding an RCA 1802 board, and a couple of z80 things, then a TI99/4a & then to a bunch of TRS-80 Color computers running os9/nitros9 which is a lot like unix on a 64k memory machine (2 megs if you stick all the aftermarket goodies in it like I did), then to the big box amigas, and thence to building my first x86 box in 97 and putting RH5.1 on it at the time. Never, ever, had a copy of windows on the premises. But I'll go lookup gnuCap and see if its useable by an old fart (70) like me. Hopefully its GPL'd. ISTR I saw something go by on freshmeat in the last few months, so I'll start there. Many thanks again Stuart. >Stuart -- 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) 99.34% setiathome rank, not too shabby for a WV hillbilly Yahoo.com and AOL/TW attorneys please note, additions to the above message by Gene Heskett are: Copyright 2005 by Maurice Eugene Heskett, all rights reserved.
