When revisiting this, I found that I had connection problems. After the correction, everything worked as expected.
Thanks Xiangjun for the help!
Shelby
Hi Xiangjun,
Thanks for helping me on this issue!
I tried connect GND directly to ADC input pin and it did not help. They still show what it would normally show, as if the signal is not connected.
Thanks,
Shelby
Hi, Shelby,
I think the 20K ohm serial resistor is too large, if you connect the GND or 1.5V to ananlog pin directly, what is the result?
BR
Xiangjun Rong