/*  SPI_Shift_MSB.txt
 Implementarea transferului utilizānd interfata
 SPI MOSI, MSB First, CPOL=0, CPHA=0 + CPHA=1  */

#define PIN_SCE   7  //Master pin 7 -> Slave SCE
#define PIN_SDIN  4  //Master pin 4 -> Slave SDIN (Slave Data In)
#define PIN_SCLK  3  //Master pin 3 -> Slave SCLK (Signal Clock)

  void setup {
//Toti pinii configurati ca DIGITAL OUT
  pinMode(PIN_SCE, OUTPUT);
  pinMode(PIN_SDIN, OUTPUT);
  pinMode(PIN_SCLK, OUTPUT);

//Pinul SCE = HIGH, pinul SCLK = LOW
  digitalWrite(PIN_SCE, HIGH);
  digitalWrite(PIN_SCLK, LOW);
}

void Shift_out(byte d) {
  digitalWrite(PIN_SCE, LOW);  //Activeaza Slave
	byte i;
	for(i = 0; i< 8; i++) { //Bucla "for" x8
		digitalWrite(PIN_SDIN, LOW);  //MOSI -> LOW
  //Ordinea bitilor MSBit -> LSBit
	if(d & 0x80) {	//Mascarea bitului cel mai semnificativ
		digitalWrite(PIN_SDIN, HIGH); //Daca bitul = 1
		}
		digitalWrite(PIN_SCLK, HIGH);  //Puls LOW->HIGH->LOW 
		digitalWrite(PIN_SCLK, LOW); // CPOL = 0, CPHA=0
		d <<= 1;	//Deplasarea spre STANGA cu o pozitie
    }	//Se repeta operatia pāna la trimiterea celor 8 biti
  digitalWrite(PIN_SCE, HIGH);  //Dezactiveaza Slave
  }	//end Shift_out