Servo causes P1 to reboot? [SOLVED]
mpark
Posts: 1,305
I have a servo connected to a P1 on a breadboard. The servo and the P1 have separate power supplies with grounds connected. Everything is fine if I keep the servo's movements below a certain speed, but once its motion becomes sufficiently abrupt, the Propeller resets.
I assume the servo is drawing too much current, but it has its own power supply (5V, 15A), which should be plenty, but even if it isn't, why should that affect the Propeller? Both power supplies are plugged into the same power strip, but that can't be it, can it? I am confused.
Comments
The simple fact that the "grounds are connected" is not enough. How they're connected is also important. Ideally, they'd be connected at a single point, right at the connector for the servo. Otherwise, the return current for the servo might pass through the supply ground for the Prop, causing a "ground bounce" that raises the Prop's ground to a point that the 3.3V supply differential falls below the reset threshold.
-Phil
uncouple your grounds and put a voltmeter between the two grounds. you may find a substsntial difference between them.
Jim
Ground is common between both, right?
You might consider putting a filter in the signal line; try a 100-ohm resistor (series) and a 0.01uF cap (signal to ground).
@"Phil Pilgrim (PhiPi)" Holy cats, that did the trick! "Ground bounce" -- what the heck? In my understanding, ground is always 0. And cows are spherical.
I'll keep the other tips in mind for future reference too.
Thanks all!
Hmmm. I thought that @ thing used to do something.
It does, but it no longer affects formatting because reasons