The Pico does expose 3 analog inputs pins. Each pin can read a voltage between 0 and 3.3V.
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* '''GP27''' - ADC1
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* '''GP28''' - also known as ADC2 (analog input 2).
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* '''GP26''' - ADC0
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* '''GP27''' - also known as ADC1 (analog input 1).
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* '''GP26''' - VSYS/3
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* '''GP26''' - also known as ADC0 (analog input 0).
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* '''AGND''' -
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* '''GP26''' - not exposed on the board pin, the voltage applied to GP26 equal VSYS/3. It can be used to monitor the external power source/battery voltage.
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* '''ADC_VREF''' - 3.3V filtered, do not applies any voltage to that pin.
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* '''AGND''' - Reference ground for analog reading.
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* '''ADC_VREF''' - Analog input voltage reference. It is the 3.3V with additional filtering. Do not applies any voltage to this pin, do not use it to supply power to the project.