I think you have the idea, especially the part about needing only a very few wires between the daughter boards. But if that is the case why have a motherboard and what do you do with an FPGA?
So my idea is that daughter cards each go in a small aluminum box of their own and connect between boxes with, as you say "just a few wires". One or more of these boxes would connect to analog signals to be measured and at least one of the boxes would provide an interface to a computer or to a human. I think it is agreed not to use any part that has a BGA. Use only parts that can be hand soldered. I do think they all can fit on the same 100x160mm size PCB because if a module to so complex that it can't fit, it can be split ion half and use two PCBs. On Wed, Dec 22, 2010 at 4:40 PM, Hal Murray <hmur...@megapathdsl.net> wrote: > > I think I'm missing the big picture. What sort of things are people > interested in building? Will they all be a reasonable fit with a single Form > Factor, Bus, and whatever? > > I've been thinking of something like a mother board with FPGA that would fit > in something like the Hammond boxes. The idea is that the FPGA is the part > that's hard for me because I can't handle soldering BGAs. All the front-end > analog stuff would go on a daughter card. > > The hardware interface between the mother/daughter cards is just a row (or 3) > of pins/sockets for 0.1 inch connectors. (or anything similar) Software > interface is TBD. It might make sense to publish a "standard" interface for > some application so the same firmware on the motherboard would work for > various front ends. > > It might make sense to put an ARM next to the FPGA. You can get a lot of CPU > for $10-20. > > I'm not sure what the back end sould look like. I'd be happy with USB or > Serial. They are dumb/simple and don't require massive protocol stacks. I > could live with Ethernet, but it really raises the bar for getting off the > ground. (I'm not interested in running a web server on my toys. All I want > is simple command/response. I'll put the web server on a PC that has access > to all the archived data.) > > It might make sense to have a back-end daughter card. > > > With that sort of setup, I think I could build a 5370 class box that I could > use for long term data collection. Does that seem reasonable? > > I don't need the full flexibility of the 5370 front end. I'm willing to use > jumpers or a soldering iron for things like AC vs DC coupling and 50 ohm > termination. > > > On the other hand, how much board space would a spectrum analyzer take? > Should we be discussing 2 sizes of projects? > > > > > -- > These are my opinions, not necessarily my employer's. I hate spam. > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- ===== Chris Albertson Redondo Beach, California _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.