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      1 /*
      2  * Author: Yevgeniy Kiveisha <yevgeniy.kiveisha (at) intel.com>
      3  * Copyright (c) 2014 Intel Corporation.
      4  *
      5  * Permission is hereby granted, free of charge, to any person obtaining
      6  * a copy of this software and associated documentation files (the
      7  * "Software"), to deal in the Software without restriction, including
      8  * without limitation the rights to use, copy, modify, merge, publish,
      9  * distribute, sublicense, and/or sell copies of the Software, and to
     10  * permit persons to whom the Software is furnished to do so, subject to
     11  * the following conditions:
     12  *
     13  * The above copyright notice and this permission notice shall be
     14  * included in all copies or substantial portions of the Software.
     15  *
     16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     17  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     18  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
     19  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
     20  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
     21  * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
     22  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
     23  */
     24 
     25 #include <iostream>
     26 #include <unistd.h>
     27 #include <stdlib.h>
     28 #include <stdexcept>
     29 
     30 #include "mlx90614.h"
     31 
     32 using namespace upm;
     33 
     34 MLX90614::MLX90614 (int bus, int devAddr) : m_i2Ctx(bus) {
     35     m_name = "MLX90614";
     36 
     37     m_i2cAddr = devAddr;
     38     m_bus = bus;
     39 
     40     mraa::Result ret = m_i2Ctx.address(m_i2cAddr);
     41     if (ret != mraa::SUCCESS) {
     42         throw std::invalid_argument(std::string(__FUNCTION__) +
     43                                     ": address() failed");
     44     }
     45 }
     46 
     47 float
     48 MLX90614::readObjectTempF(void) {
     49     return (readTemperature(MLX90614_TOBJ1) * 9 / 5) + 32;
     50 }
     51 
     52 float
     53 MLX90614::readAmbientTempF(void) {
     54     return (readTemperature(MLX90614_TA) * 9 / 5) + 32;
     55 }
     56 
     57 float
     58 MLX90614::readObjectTempC(void) {
     59     return readTemperature(MLX90614_TOBJ1);
     60 }
     61 
     62 float
     63 MLX90614::readAmbientTempC(void) {
     64     return readTemperature(MLX90614_TA);
     65 }
     66 
     67 /*
     68  * **************
     69  *  private area
     70  * **************
     71  */
     72 uint16_t
     73 MLX90614::i2cReadReg_N (int reg, unsigned int len, uint8_t * buffer) {
     74     int readByte = 0;
     75 
     76     m_i2Ctx.address(m_i2cAddr);
     77     m_i2Ctx.writeByte(reg);
     78 
     79     readByte = m_i2Ctx.read(buffer, len);
     80     return readByte;
     81 }
     82 
     83 mraa::Result
     84 MLX90614::i2cWriteReg_N (uint8_t reg, unsigned int len, uint8_t * buffer) {
     85     mraa::Result error = mraa::SUCCESS;
     86 
     87     error = m_i2Ctx.address(m_i2cAddr);
     88     error = m_i2Ctx.write(buffer, len);
     89 
     90     return error;
     91 }
     92 
     93 float
     94 MLX90614::readTemperature (uint8_t address) {
     95     uint8_t     buffer[3];
     96     float       temperature = 0;
     97 
     98     /*  Reading temperature from sensor.
     99         Answer contained of 3 bytes (TEMP_LSB | TEMP_MSB | PEC)
    100      */
    101     if (i2cReadReg_N(address, 3, buffer) > 2) {
    102         temperature = buffer[0];
    103         temperature = buffer[1] << 8;
    104 
    105         temperature *= .02;
    106         temperature -= 273.15;
    107     }
    108 
    109     return temperature;
    110 }
    111