Arduino Interfacing With Optical mouse

/*******************************/
/* OptiMouse, Benoît ROUSSEAU */
/* - dialoguer avec un ADS2051 */
/* récupérer sur une souris */
/* optique */
/*******************************/

#define BROCHE_HORLOGE 2
#define BROCHE_DONNEES 3
#define _BV(bit) (1 << (bit))

byte LectureRegistre (byte adresse)
{
int i = 7;
byte retour = 0;

pinMode (BROCHE_DONNEES, OUTPUT);
for (; i>=0; i--)
{

digitalWrite (BROCHE_HORLOGE, LOW);
digitalWrite (BROCHE_DONNEES, adresse & (1 << i));
digitalWrite (BROCHE_HORLOGE, HIGH);
}

pinMode (BROCHE_DONNEES, INPUT);
delayMicroseconds(100);

for (i=7; i>=0; i--)
{
digitalWrite (BROCHE_HORLOGE, LOW);
digitalWrite (BROCHE_HORLOGE, HIGH);
retour |= (digitalRead (BROCHE_DONNEES) << i);
}
delayMicroseconds(100);

return retour;
}

void EcritureRegistre (byte adresse, byte donnee)
{
int i = 7;

adresse |= 0x80;

pinMode (BROCHE_DONNEES, OUTPUT);
for (; i>=0; i--)
{

digitalWrite (BROCHE_HORLOGE, LOW);
digitalWrite (BROCHE_DONNEES, adresse & (1 << i));
digitalWrite (BROCHE_HORLOGE, HIGH);
}

for (i=7; i>=0; i--)
{
digitalWrite (BROCHE_HORLOGE, LOW);
digitalWrite (BROCHE_DONNEES, donnee & (1 << i));
digitalWrite (BROCHE_HORLOGE, HIGH);
}

}

void EnvoiImage()
{
byte val;
byte adr;
Serial.print (">IMG:");

EcritureRegistre (0x0a, 0x09);
for (int i=0; i<256; i++)
{
do {
adr = LectureRegistre (0x0d);
val = LectureRegistre (0x0c);
} while (val & 0x80);
// Serial.print (adr, HEX);
// Serial.print ('>', BYTE);
Serial.print (val, HEX);
// Serial.print (13, BYTE);
}

Serial.println ();
EcritureRegistre (0x0a, 0x00);
}

void setup()
{
pinMode (BROCHE_HORLOGE, OUTPUT);
pinMode (BROCHE_DONNEES, INPUT);
Serial.begin(19200);
}

void loop ()
{
if (LectureRegistre (0x02))
{
Serial.print ('>');
Serial.print (LectureRegistre (0x00), DEC);
Serial.print ('-');
Serial.print (LectureRegistre (0x01), DEC);
Serial.print ('-');
Serial.print (LectureRegistre (0x03), DEC);
Serial.print ('-');
Serial.print (LectureRegistre (0x04), DEC);
Serial.println ();
}
if (Serial.available())
{
Serial.read();
EnvoiImage();
}
}