Why on 42 pins can be switched in input_pulled in Low Power mode ?

[ferdi]

In order to get the minimal consumption in Low Power mode, unused pins must be switched as input_pullup.
(Following this tutorial : http://www.rocketscream.com/blog/docs-item/using-rtc-in-low-power-mode-on-mini-ultra-pro/#tab-id-2)
In tutorial, 42 pins can be switched as input_pullup. 34 are switched : 0-22, 25,26, 32-41.

But following hookup guide, there is only 25 usable pins : 0-24, 30,31,38.
(http://www.rocketscream.com/blog/docs-item/mini-ultra-pro-hookup-guide/#tab-id-2)

– why 42 pins can switch in input_pullup while there is only 25 usable pins ?
– what are the functions of the pins 25, 26, 33-37 & 39-41, which are in input_pullup mode in tutorial ?
– why pins 23,24, 30, 31 aren’t switched as input_pullup
– why pins 2,4 & 5 are in input_pullup mode, like unused pins, while they are radio pins.

Thanks a lot !!

[LIM PHANG MOH]

Those pins are not broken out but existed on the ATSAMD21G18A MCU.

Please see the code properly because used pins are later configured as accordingly.

[ferdi]

ok thanks,
Arduino core documentation helped to understand :
https://github.com/arduino/ArduinoCore-samd/blob/master/variants/arduino_zero/variant.cpp

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