On 02/25/2014 09:44 PM, silverdr@wfmh.org.pl wrote: > On 2014-02-25 at 20:49:07, Gerrit Heitsch (gerrit@laosinh.s.bawue.de) wrote: > >> The fun part is, if you look at a chip itself and measure just between >> +5V and GND of that chip, everything is a bit noisy, but not really >> bad. >> >> It's just that the ends of the board in relation to each other do >> funny >> things. The 1V peak-to-peak is only a few ns, and a half cycle is >> about 500ns. > > Well, this doesn’t mean such thing can be “written off” due to the length of the pulses. Of course it depends on various things but it still can be a disruptive factor for regular operations even if those are short. Also, remember, the image I mailed you shows the difference in GND potential between the 2 points far away from each other. When you take a closer look at Vcc and GND on each IC, it's still noisy, but a lot less so. >> After all, the board is working… > > “Barely” as gpz noted ;-) No, kidding - it really depends on “what”, “when” and “where”. Might as well be only a part of the circuit (“where”), which is not critical (“what”) and/or only at times “when” this part is not in use. No, my KU is working just fine, no matter what I throw at it, so the 'barely' is something I don't subscribe to. If it'd get flakey when hot/cold or with specific workloads (certain demos come to mind), I'd call it 'working barely'. Gerrit Message was sent through the cbm-hackers mailing listReceived on 2014-02-26 17:00:12
Archive generated by hypermail 2.2.0.