4.5.7 ADC Port Voltage Range Discrepency

Hello, I am seeking clarification regarding ADC port usage. I am using a Cube Blue H7 with ADSB-IN carrier board running 4.5.7. From my understanding, the Blue is identical to the Orange, just with differently sourced components. I can find that the dedicated ADC port (analog pin 8) on an Orange supports 6.6V maximum input. I would then assume the Blue does too, however I cannot find any information that supports that. I am trying to use a 0-5V output device with this port. When supplying voltage to this pin, it stops reading at 3.3V as if it is not 3.3V+ tolerant.

My relevant parameters:
BATT_MONITOR = 24
BATT_FL_VLT_MIN = 0
BATT_FL_V_MULT = 0.2
BATT_FL_PIN = 8

When the first order polynomial term is set to 1, the displayed “batt” voltage is double what the actual input is. I can set BATT_FL_FF to 0.5 to get the correctly scaled reading, however it still stops displaying at 3.3V input. I understand that the Orange is supposed to have an internal 2:1 voltage divider to allow this raised max voltage rating. The effects of the polynomial term make me think there is some sort of discrepancy between what the firmware expects in terms of a voltage divider and what the hardware spec actually is, or the Cube Blue H7 ADC port is simply not 6.6V tolerant.

I have tried pin values (BATT_FL_PIN) of 1 through 18 just in case and no luck. I have tried BATT_MONITOR set to 3 and no change in behavior. The H7 Blue’s hwdef.dat file isn’t listed in the docs, but looking at the Orange’s hwdef.dat file you can see the ADC port is PC5, which corresponds to analog pin number 8 in its CPU definition table, which is expected. Any ideas or places I can look to get a better understanding of this problem? Much appreciated

Solved:

Orange H7 & Blue H7 do not have an internal voltage divider for the dedicated ADC port (PC5). There only appears to be a divider for sensing the main board voltage (PA4) which is not useful for me. It looks like there might have been a voltage divider for PC5 at one point based on the (2) in the hwdef.dat file, but not anymore.

I do not see any obvious damage or effects caused by supplying 6V on this pin during troubleshooting/testing, but I haven’t inspected much yet.