Rx66T A/D Converter

hello everyone,

I am using the official program "Vector Control of Three-Phase Induction Motor Used in Driving a Pump RX66T Implementation Rev.1.10 - Sample Code". Currently, in order to test whether the unique value of my AD CONVERTER is correct, I give the voltage to the corner of the control board P62/AN208, but the value read from the register is not very close to the value I calculated. The current power supply is 5v, so I want to ask how to solve this problem?