On 05/30/2017 12:39 AM, Gene Heskett wrote: >>> I may have a fix to the SPI problem. There seems to be a problem in >>> clock-setting, which me apparently have been seeing. The attached >>> patch is very simple and works correct and so all the time. >> And some images how it looks now :-) > > That does look better. What sort of probes are you useing on that tek > sampler?
The probes that came with the scope: Tektronix TPP0200 (300V CAT II) 1:10 probe, 10 MOhm, <12 pF It is ringing a lot because of long (jumper-) wires attached to the pi's extension-header. But I don't care for testing purposes. >> I did see some more optimizations that can be applied. The transfers >> can almost be halved in time if the code does write/read operations >> from/to the SPI registers in a smarter way. If speed becomes an issue, >> send me a request for fixing it ;-) > > That sounds like a heck of a deal, and s/b committed. Better transfer > speeds=lower ferrors in linuxcnc. Yes, that is a big deal. The question would then be if the FPGA can keep up on the larger request packets. That I cannot tell. At the moment, the code sends 4 bytes and then reads 4 bytes. The code actually stalls until those bytes are sent/read before the next 4 bytes are processed. The BCM2835 has a 16-word fifo, which could be used asynchronously to speed up transfers. > Now if Sebastian would get us a buildbot built for armhf again, hint, > hint. :) 3-30 pf trimmer caps s/b be here around the 5th, and if what I > found works, I can get on with the build in a day or so. I'm building an SD card right now that should contain my entire setup. I'll put it on the net as soon as I get it ready so you can test it (with new kernel and patched lcnc). -- Greetings Bertho (disclaimers are disclaimed) ------------------------------------------------------------------------------ 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
