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However only 8 of these are considered GPIO
pins out of the box.
The other 9 can perform more complex
roles but I’m only interested in the basics.
All the pins except GPIO 14 & 15 come up initialised as inputs.
If you want to use them as inputs there is nothing
further you have to do to them.
GPIO 14 & 15 come up initialised as serial data lines
TX & RX so you can connect a serial terminal
to allow you to log on.