Question about PCB CAD for FPGA-based project
in [FPGA]
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From: Alex on 27 Apr 2010 14:26 Hello, I am a beginner interested to learn what PCB design software is suitable for designs using FPGA chips? I also wonder whether free software packages (such as FreePCB, ExpressPCB) are good enough for PCB designs using FPGA chips? Thank you. P.S. As I use Spartan3E 1600E Microblaze Development Board with XC3S1600E chip (FGG320 package) then I am particularly interested how to accomodate this chip on PCB.
From: Gabor on 27 Apr 2010 17:25 On Apr 27, 2:26 pm, Alex <vict...(a)gmail.com> wrote: > Hello, > > I am a beginner interested to learn what PCB design software is > suitable for designs using FPGA chips? > > I also wonder whether free software packages (such as FreePCB, > ExpressPCB) are good enough for PCB designs using FPGA chips? > > Thank you. > > P.S. > As I use Spartan3E 1600E Microblaze Development Board with XC3S1600E > chip (FGG320 package) then I am particularly interested how to > accomodate this chip on PCB. I think as soon as you start using high-density packages like BGA's with 0.8mm ball spacing, you're treading on thin ice if you think free tools and your limited experience will result in a usable board design. Check the packages for maximum layer count and whether they have the ability to create copper pours, whether they already have a symbol for your BGA package or have a tool to help generate one, etc. I've generally had a design service do this sort of design for me. I only use the "Express" stuff for little two- or four-layer designs. HTH, Gabor
From: DJ Delorie on 27 Apr 2010 17:34 On 04/27/2010 02:26 PM, Alex wrote: > I also wonder whether free software packages (such as FreePCB, > ExpressPCB) are good enough for PCB designs using FPGA chips? gEDA/PCB has had a number of success stories with high density FPGA designs. Despite being free, there are no limits on size, density, layers, or whatnot. There are some user-contributed scripts to turn pinout lists (i.e. from FPGA design software) into a "schematic" so you don't have to make those huge symbols, too. The only thing it doesn't do at the moment is blind and buried vias, although I've seen a patch to add that too...
From: Brian Drummond on 27 Apr 2010 17:52 On Tue, 27 Apr 2010 11:26:15 -0700 (PDT), Alex <victous(a)gmail.com> wrote: >Hello, > >I am a beginner interested to learn what PCB design software is >suitable for designs using FPGA chips? > >I also wonder whether free software packages (such as FreePCB, >ExpressPCB) are good enough for PCB designs using FPGA chips? > >Thank you. FreePCB is definitely up to the job, but make sure you use a Gerber viewer and double-check the output; there may be some fiddling with settings required to meet your PCB fabricator's requirements. (This goes for paid-for PCB packages too!) Caveat: my project using FreePCB didn't actually get as far as fabrication, but it was looking good. My major gripe with FreePCB was that it was Windows only. - Brian
From: Gabor on 27 Apr 2010 17:50
On Apr 27, 5:34 pm, DJ Delorie <d...(a)delorie.com> wrote: > On 04/27/2010 02:26 PM, Alex wrote: > > > I also wonder whether free software packages (such as FreePCB, > > ExpressPCB) are good enough for PCB designs using FPGA chips? > > gEDA/PCB has had a number of success stories with high density FPGA > designs. Despite being free, there are no limits on size, density, > layers, or whatnot. There are some user-contributed scripts to turn > pinout lists (i.e. from FPGA design software) into a "schematic" so you > don't have to make those huge symbols, too. > > The only thing it doesn't do at the moment is blind and buried vias, > although I've seen a patch to add that too... Unless you're dealing with severe board area restrictions I see no reason to get into blind and buried vias. You might need to up your layer count slightly without them, but overall manufacturing cost is still better with through via only. We've managed to avoid buried vias entirely here, and only used blind vias on a very small board that had no room for components except behind a BGA. That one also had back-filled via-in-pad so looking at the bare laminate you would think it wasn't drilled. |