On Sunday 22 April 2018 11:44:37 jeremy youngs wrote: > On Sun, Apr 22, 2018, 10:10 Gene Heskett <[email protected]> wrote: > > ISTR they come unprogrammed, and set to be connected to a parport > > for programming the correct config for your use into it with > > mesaflash. It has a backup recovery that must be used long enough to > > reset it to parport communications IF its been set to talk SPI, > > which is faster on the pi's but not available on *86 machines. > > Except for the missing spi capability on x86 machines, the parport > > on the x86 motherboard s/b fast enough. > > > > But note, and I emphasize this strongly, the 50 pin connectors hook > > directly into the fpga, and noises above 4 volts may blow the fpga's > > buffers, so the surge and noise protection of a 7i42TA, which also > > gives you a handy mechanical terminal arrangement to connect it to > > the outside world, and will protect it from the noise pickup from > > the stepper motors etc. I destroyed several before I understood the > > importance of that, and the one driving my lathe has had functions > > moved to different card outputs because of blown buffers. I actually > > wound up putting the pi, the 7i90, and the 3 7i42TA's in a separate > > box, and mounted that box to the lid of the old rusty box the power > > stuffs was in. Then my noise problems disappeared. > > > > I'm listening. Next week is almost all rig working, I will get at > > least 1 7i42 coming. I downloaded the 7i90 package and didn't see > > the softdmc. The idea of using generic h bridge as the drive really > > appeals to me as it eliminates propietary communication and the > > associated debugging. Also they are $20 shipped to my door in the > > states so they are easily replaceable and can affordably be kept in > > stock. Finances have been tight , as I have been doing mechanical > > upgrades as well, taking from the auto business to build the machine > > shop. > > > > > > > > But this brings up a second recommendation, which is to establish a > > single bolt as a common ground point, with the commons of everything > > else connected ONLY to this bolt. This is known as a star ground > > system. Stuff connected to the nearest ground often results in > > having more than one ground and that constitutes a ground loop, > > which acts as an antenna, picking up noise from anything radiating > > it, and this noise can easily blow gates in the fpga on the 7i90. > > That bolt should also be the only place the 3rd rounded in the US > > pin in the power cord is connected, cut them off till you've only > > one left to get rid of ground loops, just don't cut the last one! > > Yes, familiar with star grounding and ground loop isolation. I went to > machinist school out of high school, no one wanted a cocky 18 yo > machinist. I took a job at an electronic remanufacturing facility > splitting time between cosmetic work and repopulating damaged > components, we had 4 cets and a huge engineering library accessable. I > have always read a lot , and was a budding audiophile. At the time > popular electronics was my favorite magazine. They paid college > tuition at that job so I got a semester of electronics theory in > before the ways of an 18 yo boy got in the way of that job. When I > relocated to Missouri there were no electronics places in these here > hills to work. Realizing the importance of education I sought > employment as a dealership technician. 15 years of 2-3 classrooms a > month and I have a very good understanding of practical application. I > worked a couple years at an aerospace contractor, till laid off then > went back to school in a CNC focussed program. Went back to upstate NY > to take care of my father and ended up managing 28 fellers making > chips. > > > To give some credence to what I'm writing, I have never been a > > working machinist altho I've had my hands of the cranks of a lathe > > many times in my 83 years, but I am a Certified Electronics > > Technician and have used that knowledge to earn a liveing since I > > was about 14 years old. I got interested in broadcasting, and spent > > the last 22 years of my working time with an office door plaque > > saying Chief Engineer on it at some tv station. And I have the > > instruments to measure, and visually show me that noise. > > > > One thing I did when configuring this lathe, was that since the > > firmware you use mesaflash to install puts _most_ of the "canned" > > functions on the first of those 50 pin connectors, 24 i/o's per > > connector, when I started adding the gingerbread that needed gpio > > pins's, I started at the top of the 3rd connector, and I've added > > quite a bit of stuff, and figured I'd stop when I had used what was > > in the middle. That way I wasn't moving stuff around once it was > > set, and thats worked out well. I still have plenty of gpio's left > > yet, to hook up coolants, lubrication squirts etc that I haven't > > bought the hardware to do it with, yet. > > This seems pretty sound, I have an atx case here I believe I will > use. > > So if you have noise problems, you will need a scope fast enough to > see > > > the noise, and that means 100 mhz of bandwidth, not one of these $40 > > toys. Be on the lookout for used Hitachi v-1065's on ebay. Now 35 > > years old, somewhat computerized so its calibration has stayed > > valid, much moreso than tektronix stuff, its a decent tool yet. Mine > > has spent many hours in a twin piston pounder airplane as I've also > > played visiting fireman at other broadcast facilities, so I've had > > to open it and retighten all the framing screws that vibrated loose, > > and the pushbuttons are getting flaky, but the tube is still fairly > > bright and I can believe what it tells me. Dual trace, fully > > triggered of course. > > Definitely on the list, but not high enough yet, more concrete needed > in > > > the shop and a couple other machines to get functional. I did order > > a light dimmer to reform the caps on my old tectronix. It's going to > > have to do for a bit. I am really interested in a decent handheld as > > it would do multitudes of tasks. Especially on the auto side of > > life. > > Would there be harm in powering and programming the 7i90 with my > laptop without using any I/o just to familiarize myself with the board > ?
I've not seen a lappy in the last 15 years that had a parport. That will be a problem. I say 15 years because the HP I bought for a road computer in late 2002 when it became obvious I was going to be asked to play visiting fireman at some of the owner of WDTV-5's other properties, doesn't have one. And those I've looked at since were cat5 and usb only. I have a small (2) pile of Dell Dimensions with a parport, and they work well for that. $100 bill out of the back room of some computer shop that leases stuff. Get $50 off the $150 they'll ask for giving them back the HD and the winders license sticker, you'll not need either. A $30 64 gig sata ssd from newegg et all, and a lcnc install dvd you cn burn after downloading it from linuxcnc.org and you are off to the races. I have one I use to program mesa cards, and one with another of those ssd's in it running my G0704. Those drives are FAST. > > > ---------------------------------------------------------------------- >-------- 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 > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users -- Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ 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 [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
