USB programmable Open Source Hardware
in [FPGA]
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From: nobody on 29 Sep 2009 15:22 I like the site and the board, nice work! what is your intention for the board looks like everything is available for another to reproduce it. I dont get it whats the deal with only two layers, four is only two more? Sincerely, Cy
From: Antti.Lukats on 29 Sep 2009 15:29 On Sep 29, 10:22 pm, nobody <cydrollin...(a)gmail.com> wrote: > I like the site and the board, nice work! what is your intention for > the board looks like everything is available for another to reproduce > it. I dont get it whats the deal with only two layers, four is only > two more? > > Sincerely, > > Cy it is a nice board! something even i may want to have, i have one spare 100E maybe i just order this PCB :) what with 2 layers? some can do on 2, some cant. thats the difference. sure 4 is only 2 more than 2 and 6 is only 2 more than 4 so why not start with 12 layers? Antti
From: emeb on 29 Sep 2009 15:50 On Sep 29, 12:29 pm, "Antti.Luk...(a)googlemail.com" <antti.luk...(a)googlemail.com> wrote: > On Sep 29, 10:22 pm, nobody <cydrollin...(a)gmail.com> wrote: > > > I like the site and the board, nice work! what is your intention for > > the board looks like everything is available for another to reproduce > > it. I dont get it whats the deal with only two layers, four is only > > two more? > > > Sincerely, > > > Cy > > it is a nice board! > something even i may want to have, i have one spare 100E > maybe i just order this PCB :) > > what with 2 layers? > > some can do on 2, some cant. > thats the difference. > > sure 4 is only 2 more than 2 > and 6 is only 2 more than 4 > so why not start with 12 layers? > > Antti @Cy - Thanks for the compliments. The board fab I use charges significantly more for 4 layers than 2, so I try to do 2 layers only. My original intention was to make the design available for some of the folks on a mail list devoted to using FPGAs for electronic music. After I built & tested it no one else ever followed though. @Antti - Thanks. All the design materials are free for any use, although I haven't included any specific copyright claims/releases. I should probably do that. FWIW, you can buy the boards directly from the fab I use. Cost is about $32.50/ea plus ~$15 setup/shipping. Lead time is about 3wks. Here's a link to their site with the details: http://www.batchpcb.com/product_info.php?products_id=19296&check=609ea29581046016e0079ea8cd47a059 (BTW - I don't get anything out of this except a warm glow of achievement) Let me know if you have questions about it. Email addr is on my webpage. Eric
From: Nico Coesel on 29 Sep 2009 17:00 nobody <cydrollinger(a)gmail.com> wrote: >I like the site and the board, nice work! what is your intention for >the board looks like everything is available for another to reproduce >it. I dont get it whats the deal with only two layers, four is only >two more? When using really cheap pcb makers like makepcb.com a 4 layer board is twice as expensive as a 2 layer board. Besides, a 4 layer board isn't a requirement. I recenty did an FPGA design on a 2 layer board. Used the bottom layer as a ground plane and put 2 rings and a plane underneath the FPGA on the top layer. And ofcourse a size 0402 decoupling capacitor on each power supply pin. -- Failure does not prove something is impossible, failure simply indicates you are not using the right tools... "If it doesn't fit, use a bigger hammer!" --------------------------------------------------------------
From: emeb on 29 Sep 2009 17:20
On Sep 29, 2:00 pm, n...(a)puntnl.niks (Nico Coesel) wrote: > I recenty did an FPGA design on a 2 layer board. Used > the bottom layer as a ground plane and put 2 rings and a plane > underneath the FPGA on the top layer. And of course a size 0402 > decoupling capacitor on each power supply pin. That's similar to what I did: on the backside I had ground plane plus a 'snail-shell' of 3 concentric supply traces with vias through to the top where the VQ100 package sits. I used 0603 caps on every supply pin - some on the back, some on the front. Didn't have any supply problems. FWIW - I'm impressed that you used 0402 parts. I haven't tried to handle parts that small yet, but I'm getting pretty good at the 0603s. Eric |