Just tried adding the 1uF decoupling capacitor in parallel with the existing 0.1uF capacitor - it didn't decrease the high error rate.
On Saturday, September 2, 2017 at 12:08:00 PM UTC+12, ojc...@gmail.com wrote: > > So tested all of that - see table below > The servo power supply is a QM12V5A > <https://hobbyking.com/en_us/quanum-12v-5a-7-2-25-2v-dual-output-ubec.html?___store=en_us> > but > as seen below - even when this is not active, there is still a high error > rate. > Also, I am not opening and closing the serial port now - it stays open > throughout each test. I sent 100 messages for each test. Error rates are an > approximate guess. > > PWM running Servo & Servo Power Supply Active Message Mode > Error Rate > Yes Yes > RX-TX on loopback 0% - all good > Yes No > RX-TX on loopback 0% - all good > No No > RX-TX on loopback 0% - all good > Yes Yes > BBB to PC via xbee 10 - 50% - no good > Yes No > BBB to PC via xbee 10 - 50% - no good > No No > BBB to PC via xbee 0% - all good > > I don't really know what to make of it except that the problem seems to be > somewhere either in the xbee? > The xbee is connected with a 0.1uF decoupling capacitor between +3.3V and > GND close to the xbee (~25mm length from xbee GND pin thru 0.1uF Cap to > xbee +3.3V pin) > > I see some people recommend a 1uF decoupling capacitor on the xbee - maybe > I'll try adding one of those in parallel with the 0.1uF cap. > > > On Friday, September 1, 2017 at 9:22:31 AM UTC+12, Przemek Klosowski wrote: >> >> >> >> On Thu, Aug 31, 2017 at 3:13 PM, <ojc...@gmail.com> wrote: >> >>> Errors : yes garbage characters on the receiver side >>> >>> Cross-talk : so I have had a servo motor (powered from it's own ubec) >>> plugged in, however I thought that the ubec noise might be interfering, so >>> I tried running the PWM signal without any device attached (no servo ubec >>> running) and no pwm wire plugged into the beaglebone. But still had the >>> same issue. >>> >> OK--so now can you test by losing the open/close ,disconnecting the XBee >> and jumpering TX and RX and writing some simple text out and checking that >> you receive it back correctly, while running PWM. If you see errors, then >> maybe beaglebone is sensitive to crosstalk; if you don't then the crosstalk >> must be in the XBee. BTW, suppying the servo from a separate power supply >> might not fully prevent interference--it could be kickback from driving the >> servo. >> >>> >>> -- >>> For more options, visit http://beagleboard.org/discuss >>> --- >>> You received this message because you are subscribed to the Google >>> Groups "BeagleBoard" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to beagleboard...@googlegroups.com. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/beagleboard/eabc977d-e1ea-4c07-abf3-6193fe8c2518%40googlegroups.com >>> . >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/a13bf443-af43-4b66-9e7f-6610cb12d95a%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
