For one Pin, Digital input and analog input as 2 Channel.

[cw-park]

As in the circuit diagram attached where the pin resource is insufficient
For one Pin (AMULTI), I design gpio for Button and analog input as 2channel.
(This switch uses the multiplexer of the analog input.)

So, there are items to be checked as follows
Please, confirm.

1) Can it be possible to switch between Digital input (Button) and Analog input dynamically?
   ★ Looking at "Figure 21: GPIO Port and the GPIO pin details" of document (nRF 52832 _ PS _ v 1.4. Pdf).
        I think that Digital input and Analog input can be switched by "ANAEN", but There was no item corresponding to "ANAEN" in the register.

2) Please tell me the way that No.1) can be realized.

3) Is it possible to perform SAADC while switching 2 analog analog input (from Analog Multiplexer) for one Pin?
   
4) resource Is there any way to solve this issue (* 2) while it is not enough?

   (* 2) For one Pin (AMULTI), gpio for Button and analog input as 2 Channel.

[ketiljo]

You can re-define a pin between digital and analog input. The ANAEN signal comes from the ADC when it's enabled, see this register. So the pin becomes AIN only when the ADC is enabled, else it's what's defined as in the PIN_CNF register.

You might find it easier to use a I2C port extender if you're short of pins. 

[cw-park]

Thanks for your answer.

Is the register that enables the ADC specifically in the following?

ENABLE
Address offset: 0x500
(Enable or disable ADC)

[ketiljo]

Yes, that's the one

[cw-park]

THX!