ESC with 3.3v tolerant I/O?

[mikedkelly]

My flight controller can power two ESCs. On the wiring diagram I am supposed to connect the BECs from the ESCs to servo ports 0 and 1, each without the red lead wire. However, the wiring diagram specifies that port 0 is 5v tolerant I/O and port 1 is 3.3v tolerant I/O. Does the 3.3v I/O require a special ESC or do all ESCs work on either a 3.3v or 5v signal voltage?

 

[Merv]

.....Does the 3.3v I/O require a special ESC or do all ESCs work on either a 3.3v or 5v signal voltage?

ESC’s use PWM, pulse width modulation, they look at the width of the pulse in milliseconds. I don’t think the ESC’s care about the voltage of the signal pin.

Be sure to disconnect the red wires. Sounds like your flight controller supplies it’s own power.

 

[LitterBug]

Should not be an issue. Swiped from PX4 (pixhawk) documentation:

PWM interfaces are not formally standardised, however, the normal micro controllers all use TTL or CMOS voltage levels. TTL is defined as low < 0.8V and high > 2.0V with some manufacturers using > 2.4V for additional noise margin. CMOS logic is defined with similar voltage levels. 5V levels are never required to successfully switch to an on state.

Futaba, FrSky and Spektrum receivers output 3.3V or 3.0V voltage levels, as they are well above 2.4V. Pixhawk has adopted this common industry pattern and outputs 3.3V levels on recent boards.

 

[mikedkelly]

Great, thanks for the response.