On Sat, 3 Nov 2012, Kent A. Reed wrote: > Date: Sat, 03 Nov 2012 11:04:04 -0400 > From: Kent A. Reed <kentallanr...@gmail.com> > Reply-To: "Enhanced Machine Controller (EMC)" > <emc-users@lists.sourceforge.net> > To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> > Subject: [Emc-users] Revisiting [OT] measuring real-world latency, > was Re: worsk: sim parport component > > On 9/7/2012 10:04 AM, Kent A. Reed wrote: >> On 9/3/2012 4:51 PM, Michael Haberler wrote: >>> well, that seems to work just fine - no major surprises >>> >>> here's as screenshot from a logic analyzer connected to an Intel D5252 >>> parport, running the userland parport driver in sim mode >>> >>> http://static.mah.priv.at/public/uparport.png >>> >>> it's a 1kHz square; there are delays of up to 4ms in this trace. >> Logic analyzers, oscilloscopes---I know the drill but I no longer have >> easy access to such instrumentation. >> >> Has anyone come up with simple (e.g., inexpensive) ways to measure >> latencies in the range we are interested in - say a range of 1K - 100K >> pulses per second with pulse widths on the order of microseconds. >> >> Back when the world was young and we wannabe researchers avidly read >> from cover to cover in each new data-book from the likes of TI and >> Motorola, I used to design and build comparable circuits, but then I had >> the bench instrumentation to test my testers, so to speak. Now I'm in a >> catch-22 situation. >> >> If I could turn back the clock, I'd probably use this problem as a >> reason to explore FPGA, but instead I'm noodling about using a >> Beaglebone or somesuch as a starter. >> >> Thoughts, anyone? >> >> Regards, >> Kent >> > > I scan hackaday.com everyday or so. Yesterday this juicy item about > building a counter using a US$70 FPGA board showed up > http://hackaday.com/2012/11/02/building-a-100-mhz-frequency-counter/ It > convinces me I wasn't too far off. Cut off its tail, bob its nose, paint > it yellow, and I could turn this crocodile into a golden retriever. > > So much to do and so little time. > > Regards, > Kent >
Actually this is trivial for anyone using a Mesa (or maybe Pico) hardware step generator. 1. Set step generator to velocity mode in HAL 2. Set a rate of say 5 MHz (with suitable steplen and stepspace) 3. Read position FB as a time stamp every tic > > ------------------------------------------------------------------------------ > LogMeIn Central: Instant, anywhere, Remote PC access and management. > Stay in control, update software, and manage PCs from one command center > Diagnose problems and improve visibility into emerging IT issues > Automate, monitor and manage. Do more in less time with Central > http://p.sf.net/sfu/logmein12331_d2d > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ LogMeIn Central: Instant, anywhere, Remote PC access and management. Stay in control, update software, and manage PCs from one command center Diagnose problems and improve visibility into emerging IT issues Automate, monitor and manage. Do more in less time with Central http://p.sf.net/sfu/logmein12331_d2d _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
