> Sounds like its the -H I'd want too. More conserving of horizontal real > estate. And while I'm not going to add yet another potential loose > connection to the home switch setup, these bobs I have have such poor > terminals that I will cobble up a distribution point for all the stuff > that needs 5 volts. 2 bobs and 2 points on the opto so far as 5 volt > loads. As for home/limits, these cheap bobs, intended for a Mach system, > already have pullups so all they'll have to do is pull to ground with a > microswitch. > > Thanks Danny, for calling that board to my attention. > > Cheers, Gene Heskett Some FYI-
Mesa cards use a 3.3v FPGA, but you can enable a bidirectional bus switch which can convert to "mostly" 5v IO, but it's not a true 5v. Also ALL IO has pullup resistors on the Mesa, which only have an effect as inputs. Outputs are not open-collector, they're driven, but a bus switch's driven "high" is less than the 5v Vdd. This worked quite well for me. The AM882H has 5v opto-isolated IO, with integral resistors (so it's gotta be 5v to generate specified opto drive current), and they didn't common the anode or cathode. The step/dir/enable I fed by tying the anodes to 5v and the cathodes to the Mesa IO pin because drive-low is definitely 0v but drive-high isn't quite 5v. And the IO is just pulldown. My board's got a bunch of optoisolators and their outputs are just pulldowns against the Mesa inputs' built-in pullups- which is simple. BTW, about "loose connectors"- this ferrule stuff CHANGED MY LIFE on clamp-down-on-stranded-wire: https://www.amazon.com/uxcell-AWG10-Insulated-Ferrule-Terminal/dp/B00UBUR6E2/ref=sr_1_6?ie=UTF8&qid=1477283614&sr=8-6&keywords=ferrule https://www.amazon.com/Signstek-Adjusting-Ratcheting-Crimping-AWG23-10/dp/B00HPRYIL8/ref=sr_1_5?ie=UTF8&qid=1477283614&sr=8-5&keywords=ferrule&th=1 Seriously, it's amazing. I learned not to trust stranded-on-clamps. Strands fray and short, they break, they work out strand-by-strand. And having to rework it damages the wire. I've tinned stranded wire in the past, only to have it get loose later and wires fell out, and Googled this- most people say "never tin, it's too soft and gets loose and your wire falls out". Oh. Kay. This stuff is cheap and quick, it makes a 100% solid strain-relieved bond. Phoenix connectors hold them easily and they never let go. Use that 4-jaw tool, NOT the 6, if they're going in clamp connectors. Only 2 surfaces get used, so square maximizes the surface area that gets used. I showed this stuff to my hacker buds and they were all "OMG where has this been all my life???" Danny ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
