Input resistance of analog input, reset (?)

[LysAn]

Dear community,

 

my Nucleo H723ZG captures analog signals via channels (see attachment) :

• ADC12_INP15,
• ADC12_INP10 and
• ADC12_INP10

 

The second one reads a 4-20mA pressure signal from a sensor with the help of an external shunt resistor. After a system reset/reboot, the voltage there is now frozen at 0.021mA which is weird and I start suspecting that this specific analog input port has some issue...Could it be, that the input impedance of analog input ports is configurable and might go to a different state after a reset or software reboot?

Thanks in advance

Kind regards

[MasterT]

Q: .Could it be, that the input impedance of analog input ports is configurable and might go to a different state after a reset or software reboot?

 

A: No. Analog input or ADC could be damaged, since your circuits very primitive and doesn't protect uCPU against overvoltage.

You may try to test  input to adc using potentiometer.