Grove_Digital_Light_Sensor/Digital_Light_TSL2561.cpp

/*
  TSL2561 library V1.0
  2010 Copyright (c) Seeed Technology Inc.  All right reserved.
 
  Original Author: zhangkun
  
  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/
#include <Digital_Light_TSL2561.h>
#include <Arduino.h>
#include <Wire.h>
int TSL2561_CalculateLux::readRegister(int deviceAddress, int address)
{
    int value;
    Wire.beginTransmission(deviceAddress);
    Wire.write(address);                // register to read
    Wire.endTransmission();
    Wire.requestFrom(deviceAddress, 1); // read a byte
    while(!Wire.available());
    value = Wire.read();
    delay(100);
    return value; 
}

void TSL2561_CalculateLux::writeRegister(int deviceAddress, int address, int val) 
{
    Wire.beginTransmission(deviceAddress);  // start transmission to device 
    Wire.write(address);                    // send register address
    Wire.write(val);                        // send value to write
    Wire.endTransmission();                 // end transmission
    delay(100);
}
void TSL2561_CalculateLux::getLux(void)
{
    CH0_LOW=readRegister(TSL2561_ADDRESS,TSL2561_CHANNAL0L);
    CH0_HIGH=readRegister(TSL2561_ADDRESS,TSL2561_CHANNAL0H);
    //read two bytes from registers 0x0E and 0x0F
    CH1_LOW=readRegister(TSL2561_ADDRESS,TSL2561_CHANNAL1L);
    CH1_HIGH=readRegister(TSL2561_ADDRESS,TSL2561_CHANNAL1H);

    channel0=CH0_HIGH*256+CH0_LOW;
    channel1=CH1_HIGH*256+CH1_LOW;
}
void TSL2561_CalculateLux::init()
{
    writeRegister(TSL2561_ADDRESS,TSL2561_CONTROL,0x03);  // POWER UP
    writeRegister(TSL2561_ADDRESS,TSL2561_TIMING,0x11);  //High Gain (16x), integration time of 101ms
    writeRegister(TSL2561_ADDRESS,TSL2561_INTERRUPT,0x00);
}
unsigned long TSL2561_CalculateLux::calculateLux(unsigned int iGain, unsigned int tInt,int iType)
{
    switch (tInt)
    {
        case 0:  // 13.7 msec
        chScale = CHSCALE_TINT0;
        break;
        case 1: // 101 msec
        chScale = CHSCALE_TINT1;
        break;
        default: // assume no scaling
        chScale = (1 << CH_SCALE);
        break;
    }
    if (!iGain)  chScale = chScale << 4; // scale 1X to 16X
    // scale the channel values
    channel0 = (channel0 * chScale) >> CH_SCALE;
    channel1 = (channel1 * chScale) >> CH_SCALE; 

    ratio1 = 0;
    if (channel0!= 0) ratio1 = (channel1 << (RATIO_SCALE+1))/channel0;
    // round the ratio value
     unsigned long ratio = (ratio1 + 1) >> 1;
     
    switch (iType)
    {
        case 0: // T package
            if ((ratio >= 0) && (ratio <= K1T))
            {b=B1T; m=M1T;}
            else if (ratio <= K2T)
            {b=B2T; m=M2T;}
            else if (ratio <= K3T)
            {b=B3T; m=M3T;}
            else if (ratio <= K4T)
            {b=B4T; m=M4T;}
            else if (ratio <= K5T)
            {b=B5T; m=M5T;}
            else if (ratio <= K6T)
            {b=B6T; m=M6T;}
            else if (ratio <= K7T)
            {b=B7T; m=M7T;}
            else if (ratio > K8T)
            {b=B8T; m=M8T;}
            break;
        case 1:// CS package
            if ((ratio >= 0) && (ratio <= K1C))
            {b=B1C; m=M1C;}
            else if (ratio <= K2C)
            {b=B2C; m=M2C;}
            else if (ratio <= K3C)
            {b=B3C; m=M3C;}
            else if (ratio <= K4C)
            {b=B4C; m=M4C;}
            else if (ratio <= K5C)
            {b=B5C; m=M5C;}
            else if (ratio <= K6C)
            {b=B6C; m=M6C;}
            else if (ratio <= K7C)
            {b=B7C; m=M7C;}
    } 
    temp=((channel0*b)-(channel1*m));
    if(temp<0) temp=0;
    temp+=(1<<LUX_SCALE-1);
    // strip off fractional portion
    lux=temp>>LUX_SCALE;
    return (lux);
 }
 TSL2561_CalculateLux TSL2561;