Wire.requestFrom avant Wire.read ?
exemple de lecture du bus I2C, dans http://arduino.cc/en/Tutorial/SFRRangerReader
...
Wire.requestFrom(112, 2); // request 2 bytes from slave device #112
// step 5: receive reading from sensor
if(2 <= Wire.available()) // if two bytes were received
{
reading = Wire.read(); // receive high byte (overwrites previous reading)
reading = reading << 8; // shift high byte to be high 8 bits
reading |= Wire.read(); // receive low byte as lower 8 bits
Serial.println(reading); // print the reading
}
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