CUAV X7+ incorrect ADC readings

FAHD22222 · February 5, 2023, 6:41am

Hello everyone , I was testing the 6.6 Analog input and noticed that the readings are halved for some reason.

I used a power supply for input signal and an oscilloscope for measuring. I am using CUAV X7+ and the ArduPlane V4.3.3 firmware. my configs are the following, BATT4_MONITER as analog voltage only and I setup BATT4_VOLT_PIN 18 for the 6.6 ADC input.

Any help will be appreciated.

dkemxr · February 5, 2023, 1:53pm

There is a 2/1 voltage divider on that input as 3.3Vdc is the maximum for standard analog input.

FAHD22222 · February 7, 2023, 7:08am

I have discussed this with the wonderful team on Discord, this turned out to be a bug in the scale factor.

github.com/ArduPilot/ardupilot

ChibioOS: hwdef: CUAV-X7: correct 6.6v ADC scale factor

ArduPilot:master ← IamPete1:CUAV-X_pin_18_scale

opened 12:53PM - 05 Feb 23 UTC

IamPete1

+1 -1

Corrects the 6.6v pin scale factor, bug reported on discord. https://discord.com…/channels/674039678562861068/780728024756781056/1071757983937216522 Of course there is the usual dilemma about whether or not its safe to correct the bug and mess up peoples parameters..... I suspect this pin is very rarely used.

cuav_le · February 23, 2023, 2:00am

@FAHD22222 This is due to misconfiguration of hwdef.dat. Thanks for initiating a fix, but this is dangerous for current users, or we should just inform users how to fix it themselves. (Because it is used by too few users)