* Author : Uwe Kolz

uint8_t decode(int8_t dgA, uint8_t dgB) {
	static uint8_t dgHist = 0; // Wert historie
	uint8_t dgVal         = 0; // Aktueller Wert Bit 1 und 2
	
	dgVal = 0;
	if (dgA != 0) dgVal |= 0b01;
	if (dgB != 0) dgVal |= 0b10;

	if ( ( dgHist & 0b11 ) == dgVal) return 0; // no change, return

	dgHist = dgHist<<2;
	dgHist = ( dgHist | dgVal ) & 0b00111111;

/*
	switch (dgHist) // 1:1 Abtastung
	{
		case 0b100001: return  1; break;
		case 0b010010: return -1; break;

		default: return 0;	break;
	}
*/

	switch (dgHist) // 1:2 Abtastung
	{
		case 0b111000: return  1; break;
		case 0b000111: return  1; break;
		case 0b110100: return -1; break;
		case 0b001011: return -1; break;

		default: return 0;	break;
	}

/*
	switch (dgHist) // 1:4 Abtastung
	{
		case 0b111000: return  1; break;
		case 0b100001: return  1; break;
		case 0b000111: return  1; break;
		case 0b011110: return  1; break;
		case 0b110100: return -1; break;
		case 0b010010: return -1; break;
		case 0b001011: return -1; break;
		case 0b101101: return -1; break;

		default: return 0;	break;
	}
*/

	return 0;
}