Brd_pwm_volt_sel parameter - anything to consider?

ArduCopter Copter 4.5
1

Recently I was introduced to the parameter: brd_pwm_volt_sel

Screenshot from 2024-06-19 10-14-01
Screenshot from 2024-06-19 10-14-01775×432 37 KB

It came up when I started building a Hexsoon EDU-450 using the new CubePilot carrier board for this frame.

The CubePilot carrier board uses a three pin connector to the ESC - which combines the grounds from the signal and power leads to the ESC.

I’d never come across this configuration before and queried CubePilot about it. The response was that this was ok - and in some cases even preferred. However, in this configuration it was recommended that the PWM voltage be set to 5V.

I was told that brd_pwm_volt_sel defaults to “0” because there were servos/ESC’s that would not accept 5V. I was told that is is rare now.

I don’t recall ever seeing any discussion about this parameter setting - so I was wondering what other considerations should be kept in mind when setting PWM voltage to 5V. And if perhaps it should be done in all/most cases. And if so - perhaps the the parameter should default to “1”.

Thanks!

2

Defaulting to 1 would output 5V by default, potentially damaging any 3v3 device that is not 5V tolerant. Most devices these days use 3v3 logic, and many are 5V tolerant. But that doesn’t mean we should just raise the signal voltage.

I guess they are suggesting that a higher voltage signal could be less susceptible to noise, but I’m not sure I buy that as a logical standard. If you need 3v3 logic, use 3v3 logic. If 5V is required, then use that. Don’t put unnecessary band-aids where they don’t belong.