#include <Wire.h>
#define SLAVE_ADDR_8574_A 0x3e
#define SLAVE_ADDR_8574_B 0x3f


#include "Arduino.h"
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//Code issu de la librairie HX711 pour Arduino de https://github.com/bogde/HX711.git
class HX711
{
	private:
		byte PD_SCK;	// Power Down and Serial Clock Input Pin
		byte DOUT;		// Serial Data Output Pin
    	        byte GAIN;		// amplification factor
	public:
		// define clock and data pin, channel, and gain factor
		// channel selection is made by passing the appropriate gain: 128 or 64 for channel A, 32 for channel B
		// gain: 128 or 64 for channel A; channel B works with 32 gain factor only
		HX711(byte dout, byte pd_sck, byte gain = 128){ 	begin(dout, pd_sck, gain);   }
		HX711() { };
		virtual ~HX711() {}
		// Allows to set the pins and gain later than in the constructor
//////////////////////////////
		void begin(byte dout, byte pd_sck, byte gain = 128){
                	PD_SCK = pd_sck;
                	DOUT = dout;
                	pinMode(PD_SCK, OUTPUT);
                	pinMode(DOUT, INPUT);
                	set_gain(gain);
                }
//////////////////////////////
		// check if HX711 is ready
		// from the datasheet: When output data is not ready for retrieval, digital output pin DOUT is high. Serial clock
		// input PD_SCK should be low. When DOUT goes to low, it indicates data is ready for retrieval.
		bool is_ready() { return digitalRead(DOUT) == LOW; }
  		// set the gain factor; takes effect only after a call to read()
		// channel A can be set for a 128 or 64 gain; channel B has a fixed 32 gain
		// depending on the parameter, the channel is also set to either A or B
		void set_gain(byte gain = 128){
                	switch (gain) {
                		case 128: GAIN = 1; break;		// channel A, gain factor 128
                		case 64: GAIN = 3; break;		// channel A, gain factor 64
                		case 32: GAIN = 2; break;		// channel B, gain factor 32
                	}
                	digitalWrite(PD_SCK, LOW);
                	read();
                }
//////////////////////////////                
		// waits for the chip to be ready and returns a reading
		long read()  {
                	// wait for the chip to become ready
                	while (!is_ready()) {
                		// Will do nothing on Arduino but prevent resets of ESP8266 (Watchdog Issue)  yield();
                	}
                	long value = 0;
                	uint8_t data[4] = { 0,0,0,0 };
                	// pulse the clock pin 24 times to read the data
                        // https://www.arduino.cc/reference/en/language/functions/advanced-io/shiftin/
                	data[2] = shiftIn(DOUT, PD_SCK, MSBFIRST);
                	data[1] = shiftIn(DOUT, PD_SCK, MSBFIRST);
                	data[0] = shiftIn(DOUT, PD_SCK, MSBFIRST);
                	// set the channel and the gain factor for the next reading using the clock pin
                	for (unsigned int i = 0; i < GAIN; i++) {
                		digitalWrite(PD_SCK, HIGH);
                		digitalWrite(PD_SCK, LOW);
                	}               
                	// Replicate the most significant bit to pad out a 32-bit signed integer
                	if ( (data[2] & 0x80) !=0) {
                		data[3]  = 0xFF;
                	} else {
                		data[3]  = 0x00;
                	}
                	// Construct a 32-bit signed integer
                	value = (         static_cast<unsigned long>(data[3]) << 24
                			| static_cast<unsigned long>(data[2]) << 16
                			| static_cast<unsigned long>(data[1]) << 8
                			| static_cast<unsigned long>(data[0]) );
                
                	return value;
                } 
};
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
HX711 scale(A1, A0); // DOUT, SCK
#include <math.h>
#include <stddef.h>
//////////////////////////////////////////
bool detecteFrontMontantPortB(unsigned char numerobit)
{
static char ancien[8]={-1,-1,-1,-1,-1,-1,-1,-1};
bool ret=false;
unsigned char pb=LirePortB();
if (ancien[numerobit]==-1){
  for (int i=0;i<8;i++)
     ancien[i]=(pb>>i)&1;
}else{
  char actuel=(pb>>numerobit)&1;
  if ( (actuel==1) && (ancien[numerobit]==0))
    ret=true;
  else
    ret=false;
  ancien[numerobit]=actuel;
}  
return ret; 
}
//////////////////////////////////////////
unsigned char LirePortB()
{
  Wire.requestFrom((byte)SLAVE_ADDR_8574_B, (byte)1);// demande la lecture d'1 octet depuis l'adresse du pérpiphérique
  if (Wire.available()==1) //si l'octet est disponible
    return Wire.read(); // lire l'octet
  else
    return 0;
}
//////////////////////////////////////////
void EcrirePortA(unsigned char valeur)
//cette fonction pilote les 8 leds avec la valeur 8bits fournie dans le paramètre valeur 
{
  Wire.beginTransmission((byte)SLAVE_ADDR_8574_A);//démarre la transmission avec l'adresse du pérpiphérique
  Wire.write(~(byte)valeur);     //envoie la donnée complémentée car les LEDs s'allument à l'état 0
  Wire.endTransmission();
}
//////////////////////////////////////////
void setup()
{
Serial.begin(9600);
Serial.println("reset");
//scale.set_scale(250.f); //// this value is obtained by calibrating the scale with known weights
//scale.tare();
Wire.begin();        // joindre le bus i2c en tant que maître    
delay(100);
Wire.beginTransmission((byte)SLAVE_ADDR_8574_B);
Wire.write((byte)0xff);
Wire.endTransmission();//configure le composant B en entrée
pinMode(3,OUTPUT);
}
//////////////////////////////////////////
void loop()
{
}