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      1 /*
      2  * Author: Jon Trulson <jtrulson (at) ics.com>
      3  * Copyright (c) 2015 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 #pragma once
     25 
     26 #include <string>
     27 #include <iostream>
     28 
     29 #include <stdint.h>
     30 #include <stdlib.h>
     31 #include <unistd.h>
     32 #include <string.h>
     33 #include <fcntl.h>
     34 #include <errno.h>
     35 #include <termios.h>
     36 #include <sys/time.h>
     37 #include <sys/select.h>
     38 #include <sys/types.h>
     39 #include <sys/stat.h>
     40 
     41 #include <mraa/uart.h>
     42 
     43 const int MHZ16_DEFAULT_UART = 0;
     44 
     45 // protocol start and end codes
     46 const uint8_t MHZ16_START = 0x7e;
     47 const uint8_t MHZ16_END   = 0x7e;
     48 
     49 namespace upm {
     50     /**
     51      * @brief MHZ16 Serial CO2 Sensor library
     52      * @defgroup mhz16 libupm-mhz16
     53      * @ingroup seeed uart gaseous
     54      */
     55 
     56     /**
     57      * @library mhz16
     58      * @sensor mhz16
     59      * @comname Grove CO2 Sensor
     60      * @altname MHZ16 Serial CO2 Sensor
     61      * @type gaseous
     62      * @man seeed
     63      * @con uart
     64      *
     65      * @brief API support for the Grove CO2 sensor
     66      *
     67      * This class implements support for the Grove CO2 sensor.
     68      *
     69      * Its CO2 detection range is 0-2,000 ppm. It requires a
     70      * 2-3 minute warm-up time before reporting valid data.
     71      *
     72      * @image html mhz16.jpg
     73      * @snippet mhz16.cxx Interesting
     74      */
     75   class MHZ16 {
     76   public:
     77 
     78 
     79     /**
     80      * MHZ16 constructor
     81      *
     82      * @param uart Default UART to use (0 or 1)
     83      */
     84     MHZ16(int uart);
     85 
     86     /**
     87      * MHZ16 destructor
     88      */
     89     ~MHZ16();
     90 
     91     /**
     92      * Checks to see if there is data available for reading
     93      *
     94      * @param millis Number of milliseconds to wait; 0 means no waiting.
     95      * @return True if there is data available for reading
     96      */
     97     bool dataAvailable(unsigned int millis);
     98 
     99     /**
    100      * Reads any available data in a user-supplied buffer. Note: the
    101      * call blocks until data is available to be read. Use
    102      * dataAvailable() to determine whether there is data available
    103      * beforehand, to avoid blocking.
    104      *
    105      * @param buffer Buffer to hold the data read
    106      * @param len Length of the buffer
    107      * @return Number of bytes read
    108      */
    109     int readData(char *buffer, int len);
    110 
    111     /**
    112      * Writes the data in the buffer to the device
    113      *
    114      * @param buffer Buffer to hold the data read
    115      * @param len Length of the buffer
    116      * @return Number of bytes written
    117      */
    118     int writeData(char *buffer, int len);
    119 
    120     /**
    121      * Sets up proper tty I/O modes and the baud rate. The default
    122      * baud rate is 9,600 (B9600).
    123      *
    124      * @param baud Desired baud rate.
    125      * @return True if successful
    126      */
    127     bool setupTty(speed_t baud=B9600);
    128 
    129     /**
    130      * Verifies the packet header and indicates its validity
    131      *
    132      * @param pkt Packet to check
    133      * @return True if the checksum is valid, false otherwise
    134      */
    135     bool verifyPacket(uint8_t *pkt, int len);
    136 
    137     /**
    138      * Queries the sensor and returns gas (CO2) concentration and
    139      * temperature data.
    140      *
    141      * @param gas Returned gas concentration
    142      * @param temp Returned temperature in Celsius
    143      * @return True if successful
    144      */
    145     bool getData(int *gas, int *temp);
    146 
    147     /**
    148      * Sets the zero point of the sensor
    149      *
    150      */
    151     void calibrateZeroPoint();
    152 
    153   protected:
    154     int ttyFd() { return m_ttyFd; };
    155 
    156   private:
    157     mraa_uart_context m_uart;
    158     int m_ttyFd;
    159   };
    160 }
    161 
    162 
    163