The little circuit board you envision that sits on top on the Pi. Would be nice and easy to use. But there is not room on that size card for screw terminals. You are talking about building a Mesa card that is less than half the size of a Mesa card. Would be hard to do.
The way I like to do this is very low-tech. Get a big perf card, the kind used for prototyping and then solder sockets or pins to that such that my little cards mount to the bigger card then I interconnect the sockets with wire and add any passives (like resisters or capacitors) to the big perf board. This works OK for one-off work. For semi production I'd make the big card a PCB, likely using Eagle. It is still an easy design just connecting mostly 0.1 inch header pins to each other. I can assemble these cards not even needing a microscope. 0.1 headers are very large by today's standards Designing a card that plugs direct to the R-Pi 3 and carries an FPGA is a LOT of work and requires sophisticated assembly equipment, maybe even a pick and place robot, solder past masks and reflow ovens. It is cheaper to pay some outfit in China to do this work. So I tend to buy parts already mounted to carrier PCBs. Just to show the kind of thing this is here is an example http://www.ebay.com/itm/201536601580?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT That big chip in the picture is hard to solder by hand (can't be done because there is a pad under the chip) so I buy the little PCB then add pins and treats as a plug-in device. BTW this is an h-bridge that will handle up to about 30 amps, that's a good size motor. Just about any big chip you need today is available on a small PCB that also include most of the little parts you need too. Cost ism anytime less then the cost of the parts and with free shipping. Mostly the quality is first rate On Wed, Oct 26, 2016 at 1:29 AM, andy pugh <bodge...@gmail.com> wrote: > On 26 October 2016 at 00:32, Bruce Layne <linux...@thinkingdevices.com> > wrote: > > What I'd really like to see > > is a controller in the class of the Raspberry Pi with a stack-on > > daughter board for the FPGA motion control and general purpose I/O. > > I think that you might want to consider the reverse, an FPGA motion > controller with stepper drivers included + screw terminals and a slot > to plug in an SoC computer. > > The RPi Compute module, for example, is a complete RPi that fits into > a SO-DIMM slot: > http://uk.farnell.com/raspberry-pi/rpi-compute-module/compute-module- > raspberry-pi-dev/dp/2427122 > > -- > atp > "A motorcycle is a bicycle with a pandemonium attachment and is > designed for the especial use of mechanical geniuses, daredevils and > lunatics." > — George Fitch, Atlanta Constitution Newspaper, 1916 > > ------------------------------------------------------------ > ------------------ > The Command Line: Reinvented for Modern Developers > Did the resurgence of CLI tooling catch you by surprise? > Reconnect with the command line and become more productive. > Learn the new .NET and ASP.NET CLI. Get your free copy! > http://sdm.link/telerik > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Chris Albertson Redondo Beach, California ------------------------------------------------------------------------------ The Command Line: Reinvented for Modern Developers Did the resurgence of CLI tooling catch you by surprise? Reconnect with the command line and become more productive. Learn the new .NET and ASP.NET CLI. Get your free copy! http://sdm.link/telerik _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
