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, <[email protected] <javascript:>> 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.
>
>>
>> --
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