Nintendo 64 key mapping

[pinhogalloleo]

Recalbox 4.0
Controler is a bartop arcade made with GPIO
I have searched and standard setup for GPIO
stands for A..B..X..Y..L..R and Hotkey
But at recalbox seems xbox stile.
Also..A and B controller/emulator does NOT match with N64 A nor B.
How can I understand how these N64 emulator reads Z..A..B..L..R..Cup..Cdow...Cleft..Cright..analog and Start ?

To be more clear follows my Arcade Conyroller 1 map:
Selet and Stsrt at top
Digital directional at left
(Y X L
B A R) and Hotkey at right
..just like a real arcade

I want to play Mortal Kombat Trillogy..
Tried do setup A..B..L1..L2..R1..R2..select.start and hotkey but game does noy load. So I m lost with this arcade

[paradadf]

Please, always use the search function before posting. It is very likely that your question has already been answered before.
Take a look at this:
https://forum.recalbox.com/topic/5123/n64-controller

N64 C-buttons are mapped to the right analog stick, so it's difficult/impossible to play without it.

[Substring]

@pinhogalloleo so with 1 stick and 6 buttons, you expect some magic to emulate 1 d-pad + 1 analogue stick + 9 buttons ?

Your only hope is to use custom mappings