ThinkpadKeyboard.h

#ifndef KeyboardIncludes_h
#include "KeyboardIncludes.h"
#endif

#ifndef KeyboardClass
#define KeyboardClass

class ThinkpadKeyboard
{
	public:
		ThinkpadKeyboard();
		void begin();
		void getData();
		static void sendData();
		
	private:
		void _press(uint8_t);
		void _pressKeys();
		uint16_t _i, _j; /*looping variables */
		uint8_t _keysToSend, _keyPressCount;
		const uint8_t  _inputPins[TOTAL_INPUT_PINS]  = { 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, LAST_PIN /* last needs a rewire */ };
		const uint8_t _outputPins[TOTAL_OUTPUT_PINS] = { 22, 24, 26, 28, 30, 32, 34, 36, 38, 40 };
		static KeyReport _keyData;
};

ThinkpadKeyboard::ThinkpadKeyboard() /* constructor - setup pins */
{
	for(_i = 0; _i < TOTAL_OUTPUT_PINS; _i++)	/* set all _outputPins as output and set HIGH */
	{
		pinMode(_outputPins[_i], OUTPUT);
		digitalWrite(_outputPins[_i], HIGH);
	}
	for(_j = 0; _j < TOTAL_INPUT_PINS; _j++)	/* set all _inputPins as INPUT_PULLUP */
	{
		pinMode(_inputPins[_j], INPUT_PULLUP);
	}
	attachInterrupt(_inputPins[0],  pin0falling,  FALLING); /* Interrupt is triggered when we put _outputPin low */
	attachInterrupt(_inputPins[1],  pin1falling,  FALLING); /* For Due, Zero, MKR1000 and 101 boards the interrupt number = pin number. */
	attachInterrupt(_inputPins[2],  pin2falling,  FALLING); /* https://www.arduino.cc/reference/en/language/functions/external-interrupts/attachinterrupt/ */
	attachInterrupt(_inputPins[3],  pin3falling,  FALLING);
	attachInterrupt(_inputPins[4],  pin4falling,  FALLING);
	attachInterrupt(_inputPins[5],  pin5falling,  FALLING);
	attachInterrupt(_inputPins[6],  pin6falling,  FALLING);
	attachInterrupt(_inputPins[7],  pin7falling,  FALLING);
	attachInterrupt(_inputPins[8],  pin8falling,  FALLING);
	attachInterrupt(_inputPins[9],  pin9falling,  FALLING);
	attachInterrupt(_inputPins[10], pin10falling, FALLING);
	attachInterrupt(_inputPins[11], pin11falling, FALLING);
	attachInterrupt(_inputPins[12], pin12falling, FALLING);
	attachInterrupt(_inputPins[13], pin13falling, FALLING);
	attachInterrupt(_inputPins[14], pin14falling, FALLING);
	attachInterrupt(_inputPins[15], pin15falling, FALLING);
	attachInterrupt(_inputPins[16], pin16falling, FALLING);
	static HIDSubDescriptor nodeKeyboard(keyboard_hidReportDescriptor, sizeof(keyboard_hidReportDescriptor));
	HID().AppendDescriptor(&nodeKeyboard);
}

void ThinkpadKeyboard::begin() /* setup variables */
{
	for(_i = 0; _i < MAX_KEY_PRESS; _i++)
	{
		keysCurrentlyPressed[_i] = 0;
		_keyData.keys[_i] = 0;
	}
	_keyData.reserved = 0;
	_keyData.modifiers = 0;
	numKeysCurrentlyPressed = 0;
	_keysToSend = 0;
	_keyPressCount = 0;
}

void ThinkpadKeyboard::_press(uint8_t k)
{
	switch(k)
	{	
		/* do magic stuff for modifiers */ /*
		case 0x100:
		case 0x101:		
		*/
		default:			_keyData.keys[_keysToSend++] = k;
						break;
	}
}

void ThinkpadKeyboard::getData()
{
	begin(); /* Clear data from last time */
	for(outPin = 0; outPin < TOTAL_OUTPUT_PINS ; outPin++)	/* Light up all pins */
	{
		digitalWrite(_outputPins[outPin], LOW);			/* Interrupt triggered by _inputPins falling */
		digitalWrite(_outputPins[outPin], HIGH);		/* keysCurrentlyPressed[current] set to keyboardMatrixChar[outPin][ISR_call_#] in ISR */
	}
	_pressKeys();
}

void ThinkpadKeyboard::_pressKeys()
{
	/* loop through keys in keysCurrentlyPressed and put them into the keyreport
	 * _keyPressCount cycles through keysCurrentlyPressed, _keysToSend cycles through open slots in keyreport.keys
	 * loop _keyPressCount up to numKeysCurrentlyPressed 	- put that many keys into 
	 * loop _keysToSend up to MAX_KEY_PRESS			- this many slots
	  */
	for(_keysToSend = 0, _keyPressCount = 0;  
	   (_keysToSend < MAX_KEY_PRESS) && (_keyPressCount < numKeysCurrentlyPressed); 
	    _keyPressCount++) 		/* TOFIX: NKRO */
	{
		switch(keysCurrentlyPressed[_keyPressCount])
		{
			case KEY_VOL_UP:		_press(0xE0);
								_press(0x32);
								break;
			case KEY_VOL_DOWN:		_press(0xE0);
								_press(0x02);
								break;
			case KEY_MUTE:			_press(0xE0);
								_press(0x23);
			case KEY_BREAK:		_press(0xE0);
								_press(0x46);
								break;
			case KEY_PAUSE:		_press(0xE1);
								_press(0x1D);
								_press(0x45);
								_press(0xE1);
								_press(0x9D);
								_press(0xC5);
								break;
								// Above Not Working
			case KEY_POWER:		_press(KEY_LEFT_CTRL);
								_press(KEY_LEFT_ALT);
								_press(KEY_DELETE);
								break;
			case KEY_IBM:			_press(KEY_LEFT_CTRL);
								_press(KEY_LEFT_SHIFT);
								_press(KEY_F10);
								break;
			case KEY_FN:			_press(KEY_LEFT_GUI);
								break;
			case KEY_PAGE_LEFT:		_press(KEY_LEFT_CTRL);
								_press(KEY_LEFT_ARROW);
								break;
			case KEY_PAGE_RIGHT:	_press(KEY_RIGHT_CTRL);
								_press(KEY_RIGHT_ARROW);
								break;
			default:				_press(keysCurrentlyPressed[_keyPressCount]);
								break;
		}
	}
}

void ThinkpadKeyboard::sendData() /* send the keyReport over USB HID */
{
	HID().SendReport(HID_PROTOCOL_KEYBOARD,&_keyData,sizeof(_keyData));
}
#endif