Analog Input (GPIO)

• The output buffer is disabled.
• The Schmitt trigger input is inactive.
• The pull-up and -down resitors are inactive.
• Reading IDR returns “0”.

Make sure the peripheral is enabled:

• Enable GPIOx in RCC→AHBENR[0].

Configure the MODE register, for every pin that should act as analog input:

• Write 0x10 to the corresponding fields in GPIOx→MODE.