UP/DOWN buttons instead of rotary encoder for display controller

Hello,

I'm trying to implemant a 3 push buttons panel in Marlin, instead of incremental rotary encoder. But something is wrong and i can't do it working.
Display is a I2C 128x64 Oled display, and it's already working.
I know that rotary encoder is cheap and it's easier to use it. But i think it's a good way to increase my understanding and knowledge of C++ and marlin firmware (i am not new to C++, but i am not an expert).

My Marlin's release is 1.1.8 and i am devellop on an Arduino Mega board to simulate the MKS Base 1.0 board of my DiscoEasy200 printer.
I was inspired by "TinyBoy2 128x64 OLED / Encoder Panel" and "RIGIDBOT_PANEL". What i have done :

• Create a pins_3_buttons_controller.h file:
This file is inspired by pin_RIGIDBOARD.h file. It contain following lines to define UP, DWN and ENC buttons, and to undifine EN1 and EN2 inputs :

#if ENABLED(OLED_PANEL_3_BUTTONS)
	  // Direction buttons
	  #define BTN_UP	37
	  #define BTN_DWN	35
	  // 'R' button
	  #undef BTN_ENC
	  #define BTN_ENC	31
	  // Disable encoder
	  #undef BTN_EN1
	  #define BTN_EN1	-1
	  #undef BTN_EN2
	  #define BTN_EN2	-1
	#endif

• Adding following lines in Configuration.h file, near line 1607, to enable my 3 buttons panel :

//
	// I2C 128x64 OLED / 3 Buttons Panel
	//
	#define OLED_PANEL_3_BUTTONS

• Adding following lines in Conditionals_LCD.h file, near line 97, to enable U8GLIB_SSD1306 and ULTIPANEL like on the "TinyBoy2 128x64 OLED / Encoder Panel":

#elif ENABLED(OLED_PANEL_3_BUTTONS)
			#define U8GLIB_SSD1306
			#define ULTIPANEL

• Adding following lines in pin.h, near line 255, to include my pins_3_buttons_controller.h file:

#if ENABLED(OLED_PANEL_3_BUTTONS)
	  #include "pins_3_buttons_controller.h"   // Panel 3 buttons

In hardware side, my 3 buttons input is floating, and closed to ground when pressed (i follow EN_C implemant). UP is connected on digital pin37. DWN is connected on digital pin 35. ENC_C is connected on digital pin 31
So EN_C button is working, but i cannot do UP and DWN buttons working.

I have tryied to change "SET_INPUT" to "SET_INPUT_PULLUP" for UP and DWN in ultradlcd.cpp, in lines 4497 and 4500, but it's not working too.

Can you tell me what's wrong in what i have done please ?
And for general knowledge, why does all marlin's control panel use incremental rotary encoder and only one use buttons ? What the benefits of incremental rotary encoder ?

Thank you a lot, and sorry for my bad french english
Have a good day.

Edited 2 time(s). Last edit at 02/23/2018 05:44AM by pit34.