I have several books on VHDL. I've thought about doing something with them. But there aren't enough hours in a day. All I've ever done are a few PALs for simple logic. And that project went nowhere but cost $1K for the programmer. Once burned....
John > -----Original Message----- > From: Chris Albertson [mailto:[email protected]] > Sent: October-14-17 12:10 AM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] MachineKit on the BeagleBone Black > > Lots of platform solutions today. I just found a very affordable FPGA > card. Cheap enough to experiment with and if it don't work out no loss > newegg.com/Product/Product.aspx?Item=9SIADD... > <https://www.newegg.com/Product/Product.aspx?Item=9SIADD85RA5820&c > m_re=fpga-_-9SIADD85RA5820-_-Product> > > New thing like this falling under the $20 price point make up for the loss > of things like PRUs on current ARM chips. > > > > > > On Fri, Oct 13, 2017 at 10:26 PM, Frederic RIBLE <[email protected]> wrote: > > > On 2017-10-14 00:21, andy pugh wrote: > > > > I lost track of Machinekit a while ago. Do they have any > >> encoder-counting facility in the PRU? > >> > >> If they have then the rest is just config. (editing text files...) > >> > > > > Yes, Machinekit has nice PRU encoder facility with eQEP: high-speed > > quadrature + index. > > That is a strong feature of BBB. FPGA like encoder performances, without > > the cost of the FPGA. > > I am using it for synchronized motion on my EMCO-120P lathe with a > 1024ppr > > encoder and a Furaday cap. > > I have wired a custom electronics to handle the differential outputs of > > the encoder. > > Should work to synchronize Z, even when moving the spindle manually. > > My machine is WIP, so not yet tested with real chips! > > See https://youtu.be/zVUMC1mdQKg?t=23m26s > > > > PRU micro-code encoder is also available, but with lower pulse rate. I am > > using it for MPG. > > Also, I am using the PRU micro-code to manage the stepgen: high pulse rate > > can be achieved without impact on CPU load. > > > > Encoder electrical wiring as below: > > P8.12: SPINDLE A > > P8.11: SPINDLE B > > P8.16: SPINDLE INDEX > > > > Here is the portion of my hal config file: > > > > loadrt hal_arm335xQEP encoders=eQEP0,eQEP2 > > > > # Spindle encoder > > > > addf eqep.update servo-thread > > > > setp eQEP2.position-scale 4096 > > setp eQEP2.min-speed-estimate 0.2 > > setp eQEP2.capture-prescaler 5 # can measure down to 50 Hz pulses / 20 > rpm > > setp eQEP2.counter-mode 0 # Quadrature mode > > setp eQEP2.invert-B 1 > > > > net spindle-position eQEP2.position => motion.spindle-revs > > net spindle-velocity eQEP2.velocity => motion.spindle-speed-in > > net spindle-index-enable eQEP2.index-enable <=> motion.spindle-index- > enable > > > > Frederic > > http://cnc.f1oat.org > > > > > > > > ------------------------------------------------------------ > > ------------------ > > 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 > > > > > > -- > > Chris Albertson > Redondo Beach, California > ---------------------------------------------------------------------------- -- > 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 ------------------------------------------------------------------------------ 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
