Temperature and humidity sensor

temperature_and_humidity_sensor.cc

#include <machine.h>
#include <alarm.h>
#include <utility/ostream.h>
#include <i2c.h>
#include <gpio.h>
#include <cpu.h>
#include <machine/cortex_m/emote3_gptm.h>

using namespace EPOS;

OStream cout;

class TemperatureAndHumiditySensor
{
private:
    //Addresses
    enum {
        I2C_ADDR        = 0x40, //  The 7-bit base slave address is 0x40
        RH_HOLD         = 0xE5, //  Measure Relative Humidity, Hold Master Mode
        RH_NOHOLD       = 0xF5, //  Measure Relative Humidity, No Hold Master Mode
        TEMP_HOLD       = 0xE3, //  Measure Temperature, Hold Master Mode
        TEMP_NOHOLD     = 0xF3, //  Measure Temperature, No Hold Master Mode
        TEMP_PREV       = 0xE0, //  Read Temperature Value from Previous RH Measurement
        RESET_SI        = 0xFE, //  Reset
        WREG            = 0xE6, //  Write RH/T User Register 1
        RREG            = 0xE7, //  Read RH/T User Register 1
        WHCR            = 0x51, //  Write Heater Control Register
        RHCR            = 0x11, //  Read Heater Control Register
    };

    //Resolution
    enum {
        RH_12b_TEMP_14b = 0x0, ///< 12 bits for RH, 14 bits for Temp
        RH_8b_TEMP_12b = 0x1,  ///< 8 bits for RH, 12 bits for Temp
        RH_10b_TEMP_13b = 0x2, ///< 10 bits for RH, 13 bits for Temp
        RH_11b_TEMP_11b = 0x3, ///< 11 bits for RH, 11 bits for Temp
    };

public:

    TemperatureAndHumiditySensor() {
        _i2c =  new I2C(0, 'b', 1, 'b', 0); //master, SDA = PB1, SCL = PB0
    }

    int reset(void) {
        if (_i2c->put(I2C_ADDR, RESET_SI) != 0) {
            return -1;
        }

        return 0;
    }

    int getHumidity() {
        char received_data[5] = "0000";
        int umidade = 0;
        if (_i2c->put(I2C_ADDR, RH_HOLD) != 0) {
            return -1;
        }

        _i2c->get(I2C_ADDR, received_data, 2);

        umidade = (received_data[0] << 8 ) | received_data[1];
        umidade = 125 * umidade;
        umidade /= 65536;
        umidade -= 6;
        return umidade;
    }

    int getTemperature() {
        char received_data[5] = "0000";
        int temperature = 0;
        if (_i2c->put(I2C_ADDR, TEMP_HOLD) != 0) {
            return -1;
        }

        _i2c->get(I2C_ADDR, received_data, 2);
        temperature = (received_data[0] << 8) | received_data[1];
        temperature = 175 * temperature;
        temperature /= 65536;
        temperature -= 46;
        temperature -= 5;
        return temperature;
    }

private:
    I2C * _i2c;
};

int main()
{
    TemperatureAndHumiditySensor si;
    cout << "I2C Test\n";
    GPIO g('c',3, GPIO::OUTPUT);
    char received_data[5] = "0000";
    int temperature= 0, umidade=0;
    //i2c =  new I2C(0, 'b', 1, 'b', 0); //master, SDA = PB1, SCL = PB0
    while(1)
    {
        g.set(1);
        eMote3_GPTM::delay(1000000);
        g.set(0);
        eMote3_GPTM::delay(1000000);

        umidade = si.getHumidity();
        cout << "umidade()= " << umidade<< endl;

        temperature = si.getTemperature();
        cout << "getTemperature()= " << temperature<< endl;

    }
    return 0;
}