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      1 /*
      2  * Author: Jon Trulson <jtrulson (at) ics.com>
      3  * Copyright (c) 2015 Intel Corporation.
      4  *
      5  * Thanks to Adafruit for some important clues
      6  *
      7  * Permission is hereby granted, free of charge, to any person obtaining
      8  * a copy of this software and associated documentation files (the
      9  * "Software"), to deal in the Software without restriction, including
     10  * without limitation the rights to use, copy, modify, merge, publish,
     11  * distribute, sublicense, and/or sell copies of the Software, and to
     12  * permit persons to whom the Software is furnished to do so, subject to
     13  * the following conditions:
     14  *
     15  * The above copyright notice and this permission notice shall be
     16  * included in all copies or substantial portions of the Software.
     17  *
     18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     19  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
     21  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
     22  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
     23  * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
     24  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
     25  */
     26 
     27 #include <unistd.h>
     28 #include <math.h>
     29 #include <iostream>
     30 #include <stdexcept>
     31 #include <string>
     32 
     33 #include "si114x.h"
     34 
     35 using namespace upm;
     36 using namespace std;
     37 
     38 
     39 SI114X::SI114X(int bus, uint8_t address)
     40 {
     41   m_addr = address;
     42   m_uvIndex = 0;
     43 
     44   // setup our i2c link
     45   if ( !(m_i2c = mraa_i2c_init(bus)) )
     46     {
     47       throw std::invalid_argument(std::string(__FUNCTION__) +
     48                                   ": mraa_i2c_init() failed");
     49       return;
     50     }
     51 
     52   mraa_result_t rv;
     53 
     54   if ( (rv = mraa_i2c_address(m_i2c, m_addr)) != MRAA_SUCCESS)
     55     {
     56       throw std::runtime_error(std::string(__FUNCTION__) +
     57                                ": mraa_i2c_address() failed");
     58       return;
     59     }
     60 
     61   // The data sheet recommends setting the UV calibration values to
     62   // 0x7b, 0x6b, 0x01, and 0x00, however the adafruit code uses a
     63   // different set of values, presumably calibrated to their specific
     64   // implementation.  We will use those defaults here, as this was
     65   // developed on an adafruit device.
     66 
     67   // Use setUVCalibration() to set a different set of values before
     68   // calling init() if you need different values.
     69 
     70   setUVCalibration(0x29, 0x89, 0x02, 0x00);
     71 }
     72 
     73 SI114X::~SI114X()
     74 {
     75   mraa_i2c_stop(m_i2c);
     76 }
     77 
     78 bool SI114X::writeByte(uint8_t reg, uint8_t byte)
     79 {
     80   mraa_result_t rv = mraa_i2c_write_byte_data(m_i2c, byte, reg);
     81 
     82   if (rv != MRAA_SUCCESS)
     83     {
     84       throw std::runtime_error(std::string(__FUNCTION__) +
     85                                ": mraa_i2c_write_byte() failed");
     86       return false;
     87     }
     88 
     89   return true;
     90 }
     91 
     92 uint8_t SI114X::readByte(uint8_t reg)
     93 {
     94   return mraa_i2c_read_byte_data(m_i2c, reg);
     95 }
     96 
     97 uint16_t SI114X::readWord(uint8_t reg)
     98 {
     99   return mraa_i2c_read_word_data(m_i2c, reg);
    100 }
    101 
    102 void SI114X::setUVCalibration(uint8_t uvcoeff0, uint8_t uvcoeff1,
    103                               uint8_t uvcoeff2, uint8_t uvcoeff3)
    104 {
    105   m_uv_cal[0] = uvcoeff0;
    106   m_uv_cal[1] = uvcoeff1;
    107   m_uv_cal[2] = uvcoeff2;
    108   m_uv_cal[3] = uvcoeff3;
    109 };
    110 
    111 
    112 void SI114X::writeParam(SI114X_PARAM_T param, uint8_t value)
    113 {
    114   // write a parameter to the RAM parameter area
    115 
    116   // We write the value to the PARAM_WR register, then execute a
    117   // PARAM_WRITE command
    118 
    119   writeByte(REG_PARAM_WR, value);
    120 
    121   // now write it to parameter memory
    122   writeByte(REG_COMMAND, CMD_PARAM_SET | param);
    123 }
    124 
    125 uint8_t SI114X::readParam(SI114X_PARAM_T param)
    126 {
    127   // get the parameter into register REG_PARAM_READ, then read and return it.
    128 
    129   writeByte(REG_COMMAND, CMD_PARAM_QUERY | param);
    130   return readByte(REG_PARAM_READ);
    131 }
    132 
    133 void SI114X::reset()
    134 {
    135   // reset the device
    136 
    137   // zero out measuring rate
    138   writeByte(REG_MEAS_RATE0, 0);
    139   writeByte(REG_MEAS_RATE1, 0);
    140 
    141   // disable IRQ MODES
    142   // these are undocumented in the datasheet, but mentioned in Adafruit's code
    143   writeByte(REG_IRQ_MODE1, 0);
    144   writeByte(REG_IRQ_MODE2, 0);
    145 
    146   // turn off interrupts
    147   writeByte(REG_INT_CFG, 0);
    148   writeByte(REG_IRQ_STATUS, 0xff);
    149 
    150   // send a reset
    151   writeByte(REG_COMMAND, CMD_RESET);
    152   usleep(100);
    153 
    154   // set the hardware key
    155   writeByte(REG_HW_KEY, SI114X_HW_KEY);
    156   usleep(100);
    157 }
    158 
    159 void SI114X::initialize()
    160 {
    161   // initialize the device
    162 
    163   // first, reset it
    164   reset();
    165 
    166   // UV coefficients
    167   writeByte(REG_UCOEF0, m_uv_cal[0]);
    168   writeByte(REG_UCOEF1, m_uv_cal[1]);
    169   writeByte(REG_UCOEF2, m_uv_cal[2]);
    170   writeByte(REG_UCOEF3, m_uv_cal[3]);
    171 
    172   // enable UV sensor only for now
    173   writeParam(PARAM_CHLIST, CHLIST_EN_UV);
    174 
    175   // auto-measure speed - slowest - (rate * 31.25us)
    176   writeByte(REG_MEAS_RATE0, 0xff); // 7.9ms
    177 
    178   // set autorun
    179   writeByte(REG_COMMAND, CMD_ALS_AUTO);
    180 }
    181 
    182 void SI114X::update()
    183 {
    184   // for now, just update the UV Index member variable
    185   uint16_t uvi = readWord(REG_AUX_UVINDEX0);
    186 
    187   m_uvIndex = float(uvi) / 100.0;
    188 
    189   // Add any further data gets() here
    190 
    191   return;
    192 }
    193