Tom Kreyche / ADT7410

Library for ADT7410 I2C temperature sensor. Use this instead of TMP102 when you need to measure temperatures lower than -40 degrees C. The device is guaranteed to work at -55 C but will actually read lower temps. See http://mbed.org/users/tkreyche/notebook/adt7140-i2c-temperature-sensor/ for more info.

Dependents:   BLE_ADT7410_TMP102_Sample BLE_HTM_HRM1017 BLENano_SimpleTemplate_temp_170802 BLENano_SimpleTemplate_temp_170813 ... more

ADT7410.cpp

Committer:
tkreyche
Date:
2011-02-01
Revision:
0:380ac1ac0101
Child:
8:e1aee50340ec

File content as of revision 0:380ac1ac0101:

#include "ADT7410.h"


 // constructor taks paramters and initializes I2C bus
ADT7410::ADT7410(PinName sda, PinName scl, char addr, int hz)
        : i2c(sda, scl)
        , busAddr(addr)
{
    i2c.frequency(hz);
}

// destructor
ADT7410::~ADT7410() {
}

// read 13 bit temperature
float ADT7410::getTemp() {

    char wReg[1] = {TEMP_REG_ADDR};
    char rReg[2] = {0,0};
    float tFin = 0;
    int tRaw = 0;

    // set address pointer to temperature register
    i2c.write(busAddr, wReg, 1);

    // read temperature register, two bytes
    i2c.read(busAddr, rReg, 2);

    // temperature returned is only 13 bits
    // discard alarm flags in lower bits
    tRaw = (rReg[0] << 8) | (rReg[1]);
    tRaw >>= 3;

    // handle positive and negative temperatures
    // results in two's complement
    if ( tRaw & 0x1000) {
        tFin = (float) (tRaw - 8192) / 16;
    } else {
        tFin = (float) tRaw  / 16;
    }
     
    return tFin;
}

void ADT7410::setConfig(char regVal) {

    char wReg[2] = {CONFIG_REG_ADDR, regVal};
    i2c.write(busAddr, wReg, 2);
    return;
}

char ADT7410::getConfig() {

    char rReg[1] = {0};
    char wReg[1] = {CONFIG_REG_ADDR};
    // need to add repeat to supress stop
   i2c.write(busAddr, wReg, 1, 1); 
   i2c.read(busAddr, rReg, 1);
    return rReg[0];
}


// reset the sensor
void ADT7410::reset() {

    char wReg[1] = {RESET};
    i2c.write(busAddr, wReg, 1);
    // wait for sensor to reload and convert
    wait_ms(250);
    return;
}