Using the Pmod SF2 with Arduino Uno

/************************************************************************
*
* Test of the Pmod
*
*************************************************************************
* Description: Pmod_SF2
* Data is stored at the specified address and then replayed
* and displayed in the serial monitor.
*
* Material
* 1. Arduino Uno
* 2. Pmod SF2
* 3. Adafruit module TXB0108
*
************************************************************************/

#define CS 10 // Assignment of the CS pin

#include <SPI.h> // call library

int i;
int adresse=0xFF;
int donnee=0x55;
byte recu[3];
byte envoi[5];

void setup()
{
 Serial.begin(9600); // initialization of
serial communication
 SPI.begin(); // initialization of SPI port
 SPI.setDataMode(SPI_MODE0); // configuration of SPI communication in mode 0
 SPI.setClockDivider(SPI_CLOCK_DIV16); // configuration of clock at 1MHz
 pinMode(CS, OUTPUT);
 envoi[0] = adresse >> 16;
 envoi[1] = adresse >> 8;
 envoi[2] = adresse;
 envoi[3] = donnee;
 // validation écriture dans la mémoire
 digitalWrite(CS, LOW); // activation of CS line
 SPI.transfer(0x06); // write validation
 digitalWrite(CS, HIGH); // deactivation of CS line
 // effacement complet la mémoire
 digitalWrite(CS, LOW); // activation of CS line
 SPI.transfer(0xC7); // erase
 digitalWrite(CS, HIGH); // deactivation of CS line
 // écriture d'une donnée à l'adresse spécifiée
 digitalWrite(CS, LOW); // activation of CS line
 SPI.transfer(0x02); // write data a specified adress
 for (i=0;i<4;i=i+1)
    {  
    SPI.transfer(envoi[i]);
    }
 digitalWrite(CS, HIGH); // deactivation of CS line
 digitalWrite(CS, LOW); // activation of CS line
 SPI.transfer(0x04); // lock write
 digitalWrite(CS, HIGH); // deactivation of CS line
 delay(1000);
}

void loop()
{
 digitalWrite(CS, LOW); // activation of CS line
 SPI.transfer(0x03); // read data from adress
 for (i=0;i<3;i=i+1)
    {
    SPI.transfer(envoi[i]);
    }
 recu[0]=SPI.transfer(0);
 digitalWrite(CS, HIGH); // deactivation of CS line
 Serial.println(recu[0],HEX);
}