Hi, I'm using the Arduino for a fail save on two PPM receivers and I'm using interrupts 0 & 1 to read the PPM signal from both receivers. It is working pretty good, but I'm getting some jitter on the servos once or twice every second.
To find the cause of this I have disabled all servo outputs (MegaServo) and output just one channel to a digital pin directly from the interrupt callback. I am comparing the input signal and the output signal on my oscilloscope and see the input signal if perfectly clean, but the output signal is not all the time. On each jitter it passes a very long pulse.
My code seems OK because it does pass correct frames most of the time, so I am wondering if there might be another cause. The processor in the receiver has a 3.3V supply voltage and my Arduino uses 5V. The PPM signal from the receiver is also 3.3V and I wonder if this is enough. I was looking in the datasheet to check what the minimum required interrupt voltage is but can't find this information. Does anyone know more about this? I think it could be possible some interrupts are not detected because the PPM voltage is too low.
If this is not the case, any thoughts on other possible causes are very welcome.
Thanks in advance!