Hi, I'm trying to feed PX4 with a PPM signal created in software, I can't get it work correctly because I can't find the timings needed.
For example,
1)PPM pulses must be active high or active low?
2)What is minimum and maximum duration of each pulse?
3) Must I provide a fixed number of channels or the board itself counts the available channels on PPM?
Thank you!
Replies
Hey, did you manage to successfully accomplish this? And do you have any more information on this topic?
Hi, I resolved on my own, just for the curious ones:
1) For PX4 is not important since it watches for the edges, however i used an active low configuration
2) minimum and maximum duration of a ppm pulse is for PX4 between 200 and 600 us
3) the board itself counts of many channels are present with a minimum of 5
Hi there, I am trying to do the same thing, I wonder if you mentioned ppm pulse between 200 and 600us is the Pulse duration (which is 1200us - 1900us usually) or the interval between 2 edges of Pulses?
Hi duc:
I just intended that in order for the edge to be detected it is enough to set a value between 200 and 600 us. But this value is not the pwm pulse duration.
The pwm pulse duration in ppm is accounted like this:
PPM Signal:
__| 400us |________________________| 400us |__________________| |__________
<---------------------------------------------------><----------------------------------------><------------------------------....
PWM Channel 1 (1000us-1900us typ) PWM Channel 2 (...) PWM Channel n
thanks, it works great for me!