Timer controlled movement of RC servo strange

autoguider · Joined: 24 Sep 2007 Posts: 82 Location: Aachen

Dear All,
the issue was hardware based. The software is o.k.
It seems that the transistor that accepts the PW signal at the servo does not have a base resistor.
So the µP output is connected via the base-emitter pn-junction to ground. So I can be lucky that the Atmel did not crash on the overload.
I put a 10 k resistor between the µP and the servo. Then the output voltage at the µP is kept on 5V and the current is around 4 mA.
There are some high frequency oscillations on the connecting line which created some spikes at the end and the beginning of the control pulse.
You can follow the measurement history by using this link https://www.roboternetz.de/community/threads/75566-2-Servos-gegenseitige-beeinflussung/page3?p=663352#post663352
As it is a German forum I posted also in German language.
I case that you need further explanation please let me know.
Many thanks for your comments and advice.

best regards
Christian