Hi, i´m having some problems because i have 4 external interrupts from PPM radio,the calculus, 4 PWM signals and serial data, when the mototrs run i can aprecciate a change in the velocity and sound in the motors, in the oscilloscope i could see the PWM signals change the duty (as noice) but the reference is the same, i thinks that happends beacuse one interrupt or the serial data interfers qith the process of PWM, the question is how can i select the max priority for the PwmOut signals?.

Thanks.

The PWM outputs have dedicated hardware, nothing should be able to interfere with them.

How do you generate your reference signal? Because if that is noisy, and you use it to trigger your scope on, it will show the other channels to be noisy while in fact they are clean.

Yes i´m using the signal to trigger the scope, i use the PPM signals to change the pwm, i think the ppm signals culd be noisy and maybe it could be another rason, the noisy is in the 4 channels of PWM, because i can hear the sound, and also if only one is connected.

I'd try logging the values you write to PWM and to see if those have noise in them...

Greetings , I've had a lot of work but this week had the time to see what happened with the MBED, the signals of Radio are very noisy (noisy in micro seconds), and the ESC are very sensitive, now i made an average of the PPM signal and now is OK, now rarely a little noisy sound can be heard (one every 1 minute or more). Now i can finish my quadcopter, here some pics of my quad.

Thank you for your answers.

The control Board: Mbed , Razor, Tactic radio 2.4Ghz

the frame, ESC, motors, and propellers.

Have the servos got individual isolation? Hope she flies well!

Yes the PWM of the ESC have isolation, i use 6n137 optocouplers (work with 5 volts, excellent with the BEC of ESC), but the signals are inverted so i needed a not gate to invert the signals to correct the resulting. I hope upload a video soon.