Re: gEDA-user: challenge board ALMOST works
On Sun, Sep 10, 2006 at 10:49:09PM -0700, Samuel A. Falvo II wrote: On 9/10/06, DJ Delorie [EMAIL PROTECTED] wrote: However, the two oscillators tend to self-synchronize. If I let it run, one LED is on and the other is off. If I put scope probes on the buffered outputs (pins 6 and 8), I can see that the oscillators are running, they're just in lock-step. Not even out of phase. I think you accidentally re-discovered the synchronous oscillator. Since all your inverters are on the same physical chip, the output of one is likely influencing the other just enough to result in synchrony. Ideas? The only thing I can think of is inductive or capacitive coupling, but at 400 Hz? Even at such low frequencies, sharp transitions cause differential spikes to appear on adjacent wires, and it's possible that those perturbations can still cause circuits to interact. You may also want to verify for coupling via the power supply ... Ahh ... the life of an analog circuit designer. :D -- Samuel A. Falvo II ___ 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: challenge board ALMOST works
On Monday 11 September 2006 05:29, DJ Delorie wrote: I've got the prototype all soldered up. Took about six hours, including microscope inspection, mostly for the 01005's. [...] However, the two oscillators tend to self-synchronize. If I let it run, one LED is on and the other is off. If I put scope probes on the buffered outputs (pins 6 and 8), I can see that the oscillators are running, they're just in lock-step. Not even out of phase. [...] Ideas? The only thing I can think of is inductive or capacitive coupling, but at 400 Hz? Whenever the inverter switches, there's a high current peak trough the capacitor (C3) and the builtin ESD protective diodes of the inverter input. The high current can cause voltage drop or inductive disturbance, both may cause the two oscillators to lock. See the schematic for the current pathes. The Diodes are inside the schmitt-trigger IC. You should place a resistor somewhere to limit that current. (Second schematic.) When I'm using 7414 as oszillator I usually use the third circuit. This only works with IC's that have schmitt-trigger inputs. regards Werner ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: Fiducial
Dan's suggestions are similar to what I've received from one of our suppliers: Use a .050 diameter copper circle with .100 solder mask opening in 4 places. Making the part as a pin may include a drilled hole (which you don't want). What I did was make a part with one surface mount pad of the proper size. Be sure to place it on both sides of the board - they'll need it to load parts on both sides. Joe Dan McMahill wrote: Jeff VR wrote: I'm working on laying out my first PCB board. I understand that the pick and place machine uses reference points on the board called fiducials when placing my components. I'm planning on having my board assembled by a MyData 12 machine. So how do I incorporate this symbol and element on my PCB. I found a similar question on this mailing list dated a couple of years ago but it had no response. I searched the schematic symbol library and footprint libraries and I couldn't find anything obviouse. A little guidance from a seasoned PCB deasigner would be greatly appreciated. Thanks, Jeff I suggest creating a schematic element and a footprint for a fiducial and instantiate it in your schematic. I can't comment on that particular machine. In general though, you should use a minimum of 2 global fiducials and preferably 3. With 2 you can correct for x,y offsets and rotational offsets. With 3 you can correct for some nonlinear distortions like scaling, stretch, and twist. This is paraphrasing part of the IPC-7351 document. By global, I mean they're not for some particular part on the board. You should place these at 3 of the 4 board corners. The document recomments that you locate 2 diagonally across the board and the 3rd one has one x cooridinate and 1 y coordinate in common with the others. For example (X1, Y1), (X2, Y2), (X1, Y2) You may or may not need local fiducials near some high pin count fine pitch parts. If you do, place 2 of them diagonally across from each other just outside the package corners. The prefered shape and size is a filled circle of copper with solder mask completely removed. The diameter should be 1.0 mm. The diameter area free of soldermask should be 2x the diameter of the fiducial. I'd probably make an element with 1 pin to put in schematic and layout. -Dan ___ 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
gEDA-user: AT90S2313
Hi, I am a geda newbie. I am trying to design a circuit and draw the schematics using gschem. The circuit uses AT90S2313 micro for which the symbol is available under micro. But I cannot see the pin 10, Vdd and pin 20 Vcc on it. Is there any reason for not putting them in there or is there anything I need to do to unhide them? I am sorry for the stupid question. :-( -- Ramakrishnan - VU3RDD ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: AT90S2313
Ramakrishnan Muthukrishnan wrote: Hi, I am a geda newbie. I am trying to design a circuit and draw the schematics using gschem. The circuit uses AT90S2313 micro for which the symbol is available under micro. But I cannot see the pin 10, Vdd and pin 20 Vcc on it. Is there any reason for not putting them in there or is there anything I need to do to unhide them? I am sorry for the stupid question. :-( I've been working on my first design as well and had a similar question when using the ATMEG64 micro. What I found with many of the IC's I use in the library is that they were created with these pins assigned by default to the Vcc and Vdd nets. Since these pins are assigned by default the author, in an effort to reduce clutter on the symbol, didn't draw these pins and made the net attributes invisible. If you select the symbol, right click and go down into the symbol you can view these attributes. Then press 'e n' (Show invisible) followed by 'v e' (View Extents) you should see that the symbol has net attributes which assign these pins to the power and ground nets. Be sure to go up out of the symbol without saving. Someone else may be able to suggest an easier way to view this information. In my case I wanted to add some decoupling caps to the supply's of these devices so I modified the symbol to include these pins and deleted the default net assignments. Hope this helps, Jeff ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: challenge board ALMOST works
Hi DJ, On Monday 11 September 2006 16:42, DJ Delorie wrote: Werner Hoch [EMAIL PROTECTED] writes: When I'm using 7414 as oszillator I usually use the third circuit. This only works with IC's that have schmitt-trigger inputs. What values (or ratios) of R3 and R2 do you use? Depends on the frequency and the capacitor ;-). The resistor R2 is only there to improve the symmetry of the output pulse/gap ratio. You can just remove it if you don't need exact symmetry. R2 is usually 10 times larger than R3. I assume R2 is large, since it's configured as a voltage divider, but I'm trying to keep R3 large too to get a low frequency out of such tiny parts (0.01uF is the largest 01005 they make). Why in hell do you use such damn small parts ;-). regards Werner ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: Fiducial
joeft wrote: Dan's suggestions are similar to what I've received from one of our suppliers: Use a .050 diameter copper circle with .100 solder mask opening in 4 places. Making the part as a pin may include a drilled hole (which you don't want). What I did was make a part with one surface mount pad of the proper size. Be sure to place it on both sides of the board - they'll need it to load parts on both sides. Joe Dan McMahill wrote: Jeff VR wrote: I'm working on laying out my first PCB board. I understand that the pick and place machine uses reference points on the board called fiducials when placing my components. I'm planning on having my board assembled by a MyData 12 machine. So how do I incorporate this symbol and element on my PCB. I found a similar question on this mailing list dated a couple of years ago but it had no response. I searched the schematic symbol library and footprint libraries and I couldn't find anything obviouse. A little guidance from a seasoned PCB deasigner would be greatly appreciated. Thanks, Jeff I suggest creating a schematic element and a footprint for a fiducial and instantiate it in your schematic. I can't comment on that particular machine. In general though, you should use a minimum of 2 global fiducials and preferably 3. With 2 you can correct for x,y offsets and rotational offsets. With 3 you can correct for some nonlinear distortions like scaling, stretch, and twist. This is paraphrasing part of the IPC-7351 document. By global, I mean they're not for some particular part on the board. You should place these at 3 of the 4 board corners. The document recomments that you locate 2 diagonally across the board and the 3rd one has one x cooridinate and 1 y coordinate in common with the others. For example (X1, Y1), (X2, Y2), (X1, Y2) You may or may not need local fiducials near some high pin count fine pitch parts. If you do, place 2 of them diagonally across from each other just outside the package corners. The prefered shape and size is a filled circle of copper with solder mask completely removed. The diameter should be 1.0 mm. The diameter area free of soldermask should be 2x the diameter of the fiducial. I'd probably make an element with 1 pin to put in schematic and layout. -Dan ___ 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 Ok, well I haven't created any parts yet which has increased my productivity as a person new to both the tools and PCB design. I'll follow the published documentation which I recall had some discussion of fiducials. As a newbie I'm tempted to ask if creating a fiducial is so incredibly simple that it doesn't make sense to include it in the standard libraries? Has anyone posted fiducials that I could use as a starting reference? Thanks a lot for your assistance guys. Jeff ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: challenge board ALMOST works
You can just remove it if you don't need exact symmetry. I'll try a board with it removed. I don't care about symmetry, just something functional with the least number of parts. R2 is usually 10 times larger than R3. Ok, thanks. Why in hell do you use such damn small parts ;-). That's kinda the whole point! :-) ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: AT90S2313
Hi Werner, On 9/11/06, Werner Hoch [EMAIL PROTECTED] wrote: FAQ about that topic: http://geda.seul.org/wiki/geda:faq-gschem#what_should_i_do_about_power_pins_on_my_symbolsmake_them_visible_explicit_or_invisible_implicit Example schematic with labels: http://www.h-renrew.de/h/avrterminal/avrterminal.html The power labels are placed around the 3 Caps C8-C10. Thanks a lot. A Picture is worth thousand words! Makes it crystal clear. Many thanks to all. regards -- Ramakrishnan - VU3RDD ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: Fiducial
Another version you might try - uses the newer pcb file format:--Element[ Fiducial mark, no drill, .050 diameter pad FID 116000 354000 2000 2000 0 80 ] ( Pad[-1 0 1 0 5000 5000 1 1 ] ElementArc [0 0 7500 7500 0 360 1000] )-- This one has a silkscreen circle around it. Put this part (which I call FID) in whatever directory you use for local symbols, which may be something like:pcb-install-directory/newlib/your-local-symbols/FIDJoe On 9/12/06, Xtian Xultz [EMAIL PROTECTED] wrote: Well, I am still using the last Xaw version of pcb, but here is my symbol forfiducial:Element[0x715000 634500 6500 2000 0 100 0x](Pad[0 0 0 0 6000 2000 12800 F1 1 0x] )Works fine... I use the dimensions from a document that a assembler firm sentto me, I checked out some other documents explaining about fiducialdimensions, and all was about the same.I think this one would help. ___geda-user mailing listgeda-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: CPLDs and other high-density logic chips...
On Tue, Sep 05, 2006 at 08:11:47PM -0500, David Carr wrote: You can actually do without the binary only kernel modules. I use a GPL tool called xc3sprog to program my Xilinx fpga devices. Do a quick google and you'll find it. It only officially supports Spartan 3 devices but I was able to make it program a Virtex II Pro as well. Let me know if you need some help getting it set up. Oh, that's interesting. It takes in bit files rather than SVFs. I wonder if that will cause trouble in using it on older chips than Spartan3s. -- Joshua D. Boyd [EMAIL PROTECTED] http://www.jdboyd.net/ http://www.joshuaboyd.org/ ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: Fiducial
On 9/11/06, Jeff VR [EMAIL PROTECTED] wrote: joeft wrote: Dan's suggestions are similar to what I've received from one of our suppliers: Dan McMahill wrote: The prefered shape and size is a filled circle of copper with solder mask completely removed. The diameter should be 1.0 mm. The diameter area free of soldermask should be 2x the diameter of the fiducial. The fiducial below contains a 1mm diameter circle on the component and solder side of the board. The diameter of the soldermask is 2mm. (* jcl *) # FID-100PS-200MS Element[0x0 FIDUCIAL 0 0 0 0 0 100 0x0] ( Pad[0 0 0 0 3937 3937 7874 1 0x0800] Pad[0 0 0 0 3937 3937 7874 1 0x0880] ) -- http://www.luciani.org ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: AT90S2313
On Monday 11 September 2006 12:36, Ramakrishnan Muthukrishnan wrote: I am a geda newbie. I am trying to design a circuit and draw the schematics using gschem. The circuit uses AT90S2313 The AT90S2313 has been obsoleted by Atmel and replaced with the ATiny2313. AVR091: Replacing AT90S2313 by ATtiny2313 (11 pages, revision A, updated 10/03) This application note is a guide to help current AT90S2313 users convert existing designs to ATtiny2313. http://www.atmel.com/dyn/resources/prod_documents/doc4298.pdf Atmel has a bad habit of killing off parts...makes my job of dealing with regulatory bodies a nightmare. http://www.dragonsgate.net/pipermail/icc-avr/2002-October/000347.html -- http://www.softwaresafety.net/ http://www.designer-iii.com/ http://www.unusualresearch.com/ ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
