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TCS34725.h
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TCS34725.h
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#pragma once
#ifndef TCS34725_H
#define TCS34725_H
#include <Arduino.h>
#ifdef TEENSYDUINO
#include <i2c_t3.h>
#else
#include <Wire.h>
#endif
template <typename WireType>
class TCS34725_
{
static constexpr uint8_t I2C_ADDR {0x29};
static constexpr uint8_t ID_REG_PART_NUMBER {0x44};
static constexpr uint8_t COMMAND_BIT {0x80};
static constexpr float INTEGRATION_CYCLES_MIN {1.f};
static constexpr float INTEGRATION_CYCLES_MAX {256.f};
static constexpr float INTEGRATION_TIME_MS_MIN {2.4f};
static constexpr float INTEGRATION_TIME_MS_MAX {INTEGRATION_TIME_MS_MIN * INTEGRATION_CYCLES_MAX};
public:
enum class Reg : uint8_t
{
ENABLE = 0x00,
ATIME = 0x01,
WTIME = 0x03,
AILTL = 0x04,
AILTH = 0x05,
AIHTL = 0x06,
AIHTH = 0x07,
PERS = 0x0C,
CONFIG = 0x0D,
CONTROL = 0x0F,
ID = 0x12,
STATUS = 0x13,
CDATAL = 0x14,
CDATAH = 0x15,
RDATAL = 0x16,
RDATAH = 0x17,
GDATAL = 0x18,
GDATAH = 0x19,
BDATAL = 0x1A,
BDATAH = 0x1B,
};
enum class Mask : uint8_t
{
ENABLE_AIEN = 0x10,
ENABLE_WEN = 0x08,
ENABLE_AEN = 0x02,
ENABLE_PON = 0x01,
STATUS_AINT = 0x10,
STATUS_AVALID = 0x01
};
enum class Gain : uint8_t { X01, X04, X16, X60 };
struct Color { float r, g, b; };
union RawData
{
struct
{
uint16_t c;
uint16_t r;
uint16_t g;
uint16_t b;
};
uint8_t raw[sizeof(uint16_t) * 4];
};
bool attach(WireType& w = Wire)
{
wire = &w;
uint8_t x = read8(Reg::ID);
if (x != ID_REG_PART_NUMBER) return false;
power(true);
interrupt(true); // use to detect availability (available())
persistence(0x00); // every RGBC cycle generates an interrupt
return true;
}
void power(bool b)
{
if (b)
{
write8(Reg::ENABLE, (uint8_t)Mask::ENABLE_PON);
delay(3); // 2.4 ms must pass after PON is asserted before an RGBC can be initiated
write8(Reg::ENABLE, (uint8_t)Mask::ENABLE_PON | (uint8_t)Mask::ENABLE_AEN);
}
else
{
uint8_t val = read8(Reg::ENABLE);
write8(Reg::ENABLE, val & ~((uint8_t)Mask::ENABLE_PON | (uint8_t)Mask::ENABLE_AEN));
}
}
void enableColorTempAndLuxCalculation(bool b) { b_ct_lux_calc = b; }
void integrationTime(float ms) // 2.4 - 614.4 ms
{
if (ms < INTEGRATION_TIME_MS_MIN) ms = INTEGRATION_TIME_MS_MIN;
if (ms > INTEGRATION_TIME_MS_MAX) ms = INTEGRATION_TIME_MS_MAX;
uint8_t data = (uint8_t)(256.f - ms / INTEGRATION_TIME_MS_MIN);
write8(Reg::ATIME, data);
atime = data;
integration_time = ms;
}
void gain(Gain g)
{
write8(Reg::CONTROL, (uint8_t)g);
switch (g)
{
case Gain::X01: gain_value = 1.f; break;
case Gain::X04: gain_value = 4.f; break;
case Gain::X16: gain_value = 16.f; break;
case Gain::X60: gain_value = 60.f; break;
default: gain_value = 1.f; break;
}
}
void scale(float s) { scaling = s; }
// The Glass Attenuation (FA) factor used to compensate for lower light
// levels at the device due to the possible presence of glass. The GA is
// the inverse of the glass transmissivity (T), so GA = 1/T. A transmissivity
// of 50% gives GA = 1 / 0.50 = 2. If no glass is present, use GA = 1.
// See Application Note: DN40-Rev 1.0 – Lux and CCT Calculations using
// ams Color Sensors for more details.
void glassAttenuation(float v) { if (v < 1.f) v = 1.f; glass_attenuation = v; }
void persistence(uint16_t data) { write8(Reg::PERS, data); }
bool available()
{
bool b = read8(Reg::STATUS) & (uint8_t)Mask::STATUS_AINT;
if (b)
{
update();
if (b_ct_lux_calc) calcTemperatureAndLuxDN40();
clearInterrupt();
}
return b;
}
Color color() const
{
Color clr;
if (raw_data.c == 0) clr.r = clr.g = clr.b = 0;
else
{
clr.r = pow((float)raw_data.r / (float)raw_data.c, scaling) * 255.f;
clr.g = pow((float)raw_data.g / (float)raw_data.c, scaling) * 255.f;
clr.b = pow((float)raw_data.b / (float)raw_data.c, scaling) * 255.f;
if (clr.r > 255.f) clr.r = 255.f;
if (clr.g > 255.f) clr.g = 255.f;
if (clr.b > 255.f) clr.b = 255.f;
}
return clr;
}
const RawData& raw() const { return raw_data; }
float lux() const { return lx; }
float colorTemperature() const { return color_temp; }
void interrupt(bool b)
{
uint8_t r = read8(Reg::ENABLE);
if (b) r |= (uint8_t)Mask::ENABLE_AIEN;
else r &= ~(uint8_t)Mask::ENABLE_AIEN;
write8(Reg::ENABLE, r);
}
void clearInterrupt()
{
wire->beginTransmission(I2C_ADDR);
wire->write(COMMAND_BIT | 0x66);
wire->endTransmission();
}
void write8(Reg reg, uint8_t value)
{
wire->beginTransmission(I2C_ADDR);
wire->write(COMMAND_BIT | (uint8_t)reg);
wire->write(value);
wire->endTransmission();
}
uint8_t read8(Reg reg)
{
wire->beginTransmission(I2C_ADDR);
wire->write(COMMAND_BIT | (uint8_t)reg);
wire->endTransmission();
wire->requestFrom(I2C_ADDR, (uint8_t)1);
return wire->read();
}
uint16_t read16(Reg reg)
{
uint16_t x;
uint16_t t;
wire->beginTransmission(I2C_ADDR);
wire->write(COMMAND_BIT | (uint8_t)reg);
wire->endTransmission();
wire->requestFrom(I2C_ADDR, (uint8_t)2);
t = wire->read();
x = wire->read();
x <<= 8;
x |= t;
return x;
}
private:
void update()
{
wire->beginTransmission(I2C_ADDR);
wire->write(COMMAND_BIT | (uint8_t) Reg::CDATAL);
wire->endTransmission();
wire->requestFrom(I2C_ADDR, sizeof(RawData));
for (uint8_t i = 0; i < sizeof(RawData); i++)
raw_data.raw[i] = wire->read();
}
// https://github.com/adafruit/Adafruit_CircuitPython_TCS34725/blob/master/adafruit_tcs34725.py
void calcTemperatureAndLuxDN40()
{
// Device specific values (DN40 Table 1 in Appendix I)
const float GA = glass_attenuation; // Glass Attenuation Factor
static const float DF = 310.f; // Device Factor
static const float R_Coef = 0.136f; //
static const float G_Coef = 1.f; // used in lux computation
static const float B_Coef = -0.444f; //
static const float CT_Coef = 3810.f; // Color Temperature Coefficient
static const float CT_Offset = 1391.f; // Color Temperatuer Offset
// Analog/Digital saturation (DN40 3.5)
float saturation = (256 - atime > 63) ? 65535 : 1024 * (256 - atime);
// Ripple saturation (DN40 3.7)
if (integration_time < 150)
saturation -= saturation / 4;
// Check for saturation and mark the sample as invalid if true
if (raw_data.c >= saturation)
return;
// IR Rejection (DN40 3.1)
float sum = raw_data.r + raw_data.g + raw_data.b;
float c = raw_data.c;
float ir = (sum > c) ? ((sum - c) / 2.f) : 0.f;
float r2 = raw_data.r - ir;
float g2 = raw_data.g - ir;
float b2 = raw_data.b - ir;
// Lux Calculation (DN40 3.2)
float g1 = R_Coef * r2 + G_Coef * g2 + B_Coef * b2;
float cpl = (integration_time * gain_value) / (GA * DF);
lx = g1 / cpl;
// CT Calculations (DN40 3.4)
color_temp = CT_Coef * b2 / r2 + CT_Offset;
}
WireType* wire;
float scaling {2.5f};
// for lux & temperature
bool b_ct_lux_calc {true};
float lx;
float color_temp;
RawData raw_data;
float gain_value {1.f};
uint8_t atime {0xFF};
float integration_time {2.4f}; // [ms]
float glass_attenuation {1.f};
};
#ifdef TEENSYDUINO
using TCS34725 = TCS34725_<i2c_t3>;
#else
using TCS34725 = TCS34725_<TwoWire>;
#endif
#endif // TCS34725_H