Servo PWM

btomko

For all servos either digital or analog, does it matter what the actual voltage magnitude of the PWM signal is?· For instance, is a pulse of 19 ms at 0v followed by a pulse of 1 ms at 3.3v the same thing as a pulse of 19 ms at 0v followed by a pulse of 1 ms at 5v.· I'm not sure if servo's average the voltage you send it in the PWM signal or if the voltage just needs to be high enough to trigger a digital transistor inside.· I want to be able to switch between a pwm signal coming from a receiver and one from the propeller chip, and I'm trying to determine if I should use a digital 2 to 1 mux or an analog 2 to 1 mux.· I have a receiver that sends pwm signals where 0v is low and 3.3v is high, but I'm not sure if all receivers use those voltage levels for their pwm signals.

Beau Schwabe

btomko,

In most cases, the servo I/O threshold will have absolutely no problem receiving a·3.3V signal.· If there is any doubt you can use a transistor configured as an Emitter follower.· Configured this way there is no signal inversion to deal with.

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Beau Schwabe

IC Layout Engineer
Parallax, Inc.