#include <Wire.h>

float L = 0.5; //Leakage Factor.
int delta_threshold = 500;
int trigger_threshold = 1000;


byte FDC = 0x2A;// FDC address either 0x2A or 0x2B;
//byte FDC = 0x2B;// FDC address either 0x2A or 0x2B;


//Build the complete conversion result from the specific channel
unsigned long readChannel(byte Channel) {
unsigned long val = 0;
uint16_t c = 0;
uint16_t d = 0;
c = readValue(FDC, 2 * Channel);
d = readValue(FDC, 2 * Channel + 1);
val = c;
val <<= 16;
val += d;
return val;
}

//Read bytes from register channel specified
word readValue (int FDC, int reg) {
byte a = 0;
byte b = 0;
uint16_t value = 0;
Wire.beginTransmission(FDC);
Wire.write(reg);
Wire.endTransmission();
Wire.requestFrom(FDC, 2);
while (Wire.available())
{
a = Wire.read();
b = Wire.read();
}
value = a;
value <<= 8;
value += b;
return value;
}


void monitor() {
long current[4];
long delta[4];
long deltaSum[4];
long last[4];
boolean sign[4];
boolean triggered[4];
long trigCounts[4];
byte n;
unsigned long zt, target;

for (n = 0; n < 4; n++) {
current[n] = readChannel(n);
delta[n] = 0;
deltaSum[n] = 0;
last[n] = 0;
sign[n] = false;
triggered[n] = false;
trigCounts[n] = 0;
}
long rc;
zt = millis();
target = zt + 1000;

for (;;) {
for (n = 0; n < 4; n++) {
last[n] = current[n];
rc = readChannel(n);
current[n] = (3 * current[n] + rc) / 4;
//Serial.println(current[n]);

delta[n] = (current[n] - last[n]);
sign[n] = (delta[n] > 0);
delta[n] = abs(delta[n]);

if (delta[n] > delta_threshold) {
deltaSum[n] += delta[n];
if ((sign[n] == 0) && (deltaSum[n] > trigger_threshold)) {
// detect only downward changes
if (triggered[n] == false) {
trigCounts[n]++;
//avoid multiple counts for single triggers;
//triggered[] is reset to false only once per second
}
triggered[n] = true;
// Serial.print(deltaSum[n]);
// Serial.print('\t');
// Serial.print(sign[n]);
// Serial.print('\t');
// Serial.println("DETECT!");
}
} else {
deltaSum[n] *= L;
// Serial.print(deltaSum[n]);
// Serial.print('\t');
// Serial.print(sign[n]);
// Serial.print('\t');
// Serial.println("-");
}

}

delay(50);

zt = millis();
if (zt >= target) {
target += 1000;
// accept only 1 event per second across all sensors
for (n = 0; n < 4; n++) {
triggered[n] = false;
}
for (n = 0; n < 4; n++) {
Serial.print(trigCounts[n]);
Serial.print('\t');
}
Serial.println("");
}
}
}


//Configuring the FDC2214
void writeConfig(int FDC, byte reg, byte MSB, byte LSB) {
Wire.beginTransmission(FDC);
Wire.write(reg);
Wire.write(MSB);
Wire.write(LSB);
Wire.endTransmission();
}

void Configure() {
// based on best results with the TI demo program
writeConfig(FDC, 0x14, 0x10, 0x01);//CLOCK_DIVIDERS_CH0
writeConfig(FDC, 0x1E, 0x88, 0x00);//DRIVE_CURRENT_CH0
writeConfig(FDC, 0x10, 0x04, 0x00);//SETTLECOUNT_CH0
writeConfig(FDC, 0x08, 0xFF, 0xFF);//RCOUNT_CH0

writeConfig(FDC, 0x15, 0x10, 0x01);//CLOCK_DIVIDERS_CH1
writeConfig(FDC, 0x1F, 0x88, 0x00);//DRIVE_CURRENT_CH1
writeConfig(FDC, 0x11, 0x04, 0x00);//SETTLECOUNT_CH1
writeConfig(FDC, 0x09, 0xFF, 0xFF);//RCOUNT_CH1

writeConfig(FDC, 0x16, 0x10, 0x01);//CLOCK_DIVIDERS_CH2
writeConfig(FDC, 0x20, 0x88, 0x00);//DRIVE_CURRENT_CH2
writeConfig(FDC, 0x12, 0x04, 0x00);//SETTLECOUNT_CH2
writeConfig(FDC, 0x0A, 0xFF, 0xFF);//RCOUNT_CH2

writeConfig(FDC, 0x17, 0x10, 0x01);//CLOCK_DIVIDERS_CH3
writeConfig(FDC, 0x21, 0x88, 0x00);//DRIVE_CURRENT_CH3
writeConfig(FDC, 0x13, 0x04, 0x00);//SETTLECOUNT_CH3
writeConfig(FDC, 0x0B, 0xFF, 0xFF);//RCOUNT_CH3

writeConfig(FDC, 0x19, 0x00, 0x01);//ERROR_CONFIG
writeConfig(FDC, 0x1B, 0xC2, 0x0C);//MUX_CONFIG
writeConfig(FDC, 0x1A, 0x1E, 0x01);//CONFIG
}


void setup() {
Wire.begin();
Serial.begin(9600);
Serial.println("And so it begins");
Configure();
}

void loop() {
Wire.beginTransmission(FDC);
monitor();
}