Analog Devices / CN0357

CN0357 toxic gas measurement sensor

Dependencies:   AD5270 AD7790

Dependents:   CN0357-helloworld

For additional information check out the mbed page of the Analog Devices wiki: https://wiki.analog.com/resources/tools-software/mbed-drivers-all

CN0357.cpp@1:19e1bf69dc75, 2016-05-19 (annotated)

Committer:
adisuciu
Date:
Thu May 19 08:46:59 2016 +0000
Revision:
1:19e1bf69dc75
Parent:
0:db2cdeb6928a 
Added library dependencies

Who changed what in which revision?

UserRevisionLine numberNew contents of line
adisuciu 0:db2cdeb6928a 1 /**
adisuciu 0:db2cdeb6928a 2 * @file cn0357.cpp
adisuciu 0:db2cdeb6928a 3 * @brief Source file for CN0357
adisuciu 0:db2cdeb6928a 4 * @author Analog Devices Inc.
adisuciu 0:db2cdeb6928a 5 *
adisuciu 0:db2cdeb6928a 6 * For support please go to:
adisuciu 0:db2cdeb6928a 7 * Github: https://github.com/analogdevicesinc/mbed-adi
adisuciu 0:db2cdeb6928a 8 * Support: https://ez.analog.com/community/linux-device-drivers/microcontroller-no-os-drivers
adisuciu 0:db2cdeb6928a 9 * Product: www.analog.com/EVAL-CN0357-ARDZ
adisuciu 0:db2cdeb6928a 10 * More: https://wiki.analog.com/resources/tools-software/mbed-drivers-all
adisuciu 0:db2cdeb6928a 11
adisuciu 0:db2cdeb6928a 12 ********************************************************************************
adisuciu 0:db2cdeb6928a 13 * Copyright 2016(c) Analog Devices, Inc.
adisuciu 0:db2cdeb6928a 14 *
adisuciu 0:db2cdeb6928a 15 * All rights reserved.
adisuciu 0:db2cdeb6928a 16 *
adisuciu 0:db2cdeb6928a 17 * Redistribution and use in source and binary forms, with or without
adisuciu 0:db2cdeb6928a 18 * modification, are permitted provided that the following conditions are met:
adisuciu 0:db2cdeb6928a 19 * - Redistributions of source code must retain the above copyright
adisuciu 0:db2cdeb6928a 20 * notice, this list of conditions and the following disclaimer.
adisuciu 0:db2cdeb6928a 21 * - Redistributions in binary form must reproduce the above copyright
adisuciu 0:db2cdeb6928a 22 * notice, this list of conditions and the following disclaimer in
adisuciu 0:db2cdeb6928a 23 * the documentation and/or other materials provided with the
adisuciu 0:db2cdeb6928a 24 * distribution.
adisuciu 0:db2cdeb6928a 25 * - Neither the name of Analog Devices, Inc. nor the names of its
adisuciu 0:db2cdeb6928a 26 * contributors may be used to endorse or promote products derived
adisuciu 0:db2cdeb6928a 27 * from this software without specific prior written permission.
adisuciu 0:db2cdeb6928a 28 * - The use of this software may or may not infringe the patent rights
adisuciu 0:db2cdeb6928a 29 * of one or more patent holders. This license does not release you
adisuciu 0:db2cdeb6928a 30 * from the requirement that you obtain separate licenses from these
adisuciu 0:db2cdeb6928a 31 * patent holders to use this software.
adisuciu 0:db2cdeb6928a 32 * - Use of the software either in source or binary form, must be run
adisuciu 0:db2cdeb6928a 33 * on or directly connected to an Analog Devices Inc. component.
adisuciu 0:db2cdeb6928a 34 *
adisuciu 0:db2cdeb6928a 35 * THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES "AS IS" AND ANY EXPRESS OR
adisuciu 0:db2cdeb6928a 36 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, NON-INFRINGEMENT,
adisuciu 0:db2cdeb6928a 37 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
adisuciu 0:db2cdeb6928a 38 * IN NO EVENT SHALL ANALOG DEVICES BE LIABLE FOR ANY DIRECT, INDIRECT,
adisuciu 0:db2cdeb6928a 39 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
adisuciu 0:db2cdeb6928a 40 * LIMITED TO, INTELLECTUAL PROPERTY RIGHTS, PROCUREMENT OF SUBSTITUTE GOODS OR
adisuciu 0:db2cdeb6928a 41 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
adisuciu 0:db2cdeb6928a 42 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
adisuciu 0:db2cdeb6928a 43 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
adisuciu 0:db2cdeb6928a 44 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
adisuciu 0:db2cdeb6928a 45 *
adisuciu 0:db2cdeb6928a 46 ********************************************************************************/
adisuciu 0:db2cdeb6928a 47
adisuciu 0:db2cdeb6928a 48 #include "mbed.h"
adisuciu 0:db2cdeb6928a 49 #include "AD7790.h"
adisuciu 0:db2cdeb6928a 50 #include "AD5270.h"
adisuciu 0:db2cdeb6928a 51 #include "CN0357.h"
adisuciu 0:db2cdeb6928a 52
adisuciu 0:db2cdeb6928a 53 /**
adisuciu 0:db2cdeb6928a 54 * @brief CN0357 constructor
adisuciu 0:db2cdeb6928a 55 * @param CSAD7790 - (optional)chip select of the AD7790
adisuciu 0:db2cdeb6928a 56 * @param CSAD5270 - (optional)chip select of the AD5270
adisuciu 0:db2cdeb6928a 57 * @param MOSI - (optional)pin of the SPI interface
adisuciu 0:db2cdeb6928a 58 * @param MISO - (optional)pin of the SPI interface
adisuciu 0:db2cdeb6928a 59 * @param SCK - (optional)pin of the SPI interface
adisuciu 0:db2cdeb6928a 60 */
adisuciu 0:db2cdeb6928a 61 CN0357::CN0357(PinName CSAD7790, PinName CSAD5270, PinName MOSI, PinName MISO,
adisuciu 0:db2cdeb6928a 62 PinName SCK) :
adisuciu 0:db2cdeb6928a 63 _vref(1.2), _sensor_sensitivity(0), _sensor_range(0), _RDACvalue(0),
adisuciu 0:db2cdeb6928a 64 ad7790(_vref, CSAD7790, MOSI, MISO, SCK), ad5270(CSAD5270, 20000.0, MOSI, MISO, SCK)
adisuciu 0:db2cdeb6928a 65
adisuciu 0:db2cdeb6928a 66 {
adisuciu 0:db2cdeb6928a 67 }
adisuciu 0:db2cdeb6928a 68
adisuciu 0:db2cdeb6928a 69 /**
adisuciu 0:db2cdeb6928a 70 * @brief initializes the AD7790 and the AD5270
adisuciu 0:db2cdeb6928a 71 * @param range - range of the sensor used (in ppm)
adisuciu 0:db2cdeb6928a 72 * @param sensitivity - sensitivity of the sensor (A/ppm)
adisuciu 0:db2cdeb6928a 73 * @param jp - (optional)jumper configuration of the CN0357
adisuciu 0:db2cdeb6928a 74 * @param mode_val - (optional)if jp is set to InternalADC, configures the mode register of the Internal ADC
adisuciu 0:db2cdeb6928a 75 * @param filter_val - (optional)if jp is set to InternalADC, configures the filter register of the Internal ADC
adisuciu 0:db2cdeb6928a 76 */
adisuciu 0:db2cdeb6928a 77 void CN0357::init(float range, float sensitivity, JumperConfig_t jp, uint8_t mode_val, uint8_t filter_val)
adisuciu 0:db2cdeb6928a 78 {
adisuciu 0:db2cdeb6928a 79 ad5270.frequency(500000);
adisuciu 0:db2cdeb6928a 80 ad7790.frequency(500000);
adisuciu 0:db2cdeb6928a 81
adisuciu 0:db2cdeb6928a 82 float resistance = set_sensor_parameters(range, sensitivity);
adisuciu 0:db2cdeb6928a 83
adisuciu 0:db2cdeb6928a 84 if(jp == INTERNAL_AD7790) {
adisuciu 0:db2cdeb6928a 85 _AD7790_init(mode_val, filter_val);
adisuciu 0:db2cdeb6928a 86 }
adisuciu 0:db2cdeb6928a 87 _rdac_init(resistance);
adisuciu 0:db2cdeb6928a 88 }
adisuciu 0:db2cdeb6928a 89
adisuciu 0:db2cdeb6928a 90 /**
adisuciu 0:db2cdeb6928a 91 * @brief initializes the RDAC and sets SDO to HiZ
adisuciu 0:db2cdeb6928a 92 * @param resistance - resistance value to initialize the RDAC
adisuciu 0:db2cdeb6928a 93 * @return
adisuciu 0:db2cdeb6928a 94 */
adisuciu 0:db2cdeb6928a 95 void CN0357::_rdac_init(float resistance)
adisuciu 0:db2cdeb6928a 96 {
adisuciu 0:db2cdeb6928a 97 /* RDAC initialization*/
adisuciu 0:db2cdeb6928a 98 /* Compute for the nearest RDAC value from given resistance and save data to the structure */
adisuciu 0:db2cdeb6928a 99 set_RDAC_value(resistance);
adisuciu 0:db2cdeb6928a 100 /* Set AD5270 SDO to Hi-Z */
adisuciu 0:db2cdeb6928a 101 ad5270.set_SDO_HiZ();
adisuciu 0:db2cdeb6928a 102 }
adisuciu 0:db2cdeb6928a 103
adisuciu 0:db2cdeb6928a 104 /**
adisuciu 0:db2cdeb6928a 105 * @brief initializes the AD7790
adisuciu 0:db2cdeb6928a 106 * @param mode_val - configures the mode register of the Internal ADC
adisuciu 0:db2cdeb6928a 107 * @param filter_val - configures the filter register of the Internal ADC
adisuciu 0:db2cdeb6928a 108 */
adisuciu 0:db2cdeb6928a 109 void CN0357::_AD7790_init(uint8_t mode_val, uint8_t filter_val)
adisuciu 0:db2cdeb6928a 110 {
adisuciu 0:db2cdeb6928a 111 ad7790.reset();
adisuciu 0:db2cdeb6928a 112 wait_ms(50);
adisuciu 0:db2cdeb6928a 113
adisuciu 0:db2cdeb6928a 114 ad7790.write_mode_reg(mode_val);
adisuciu 0:db2cdeb6928a 115 wait_us(2);
adisuciu 0:db2cdeb6928a 116
adisuciu 0:db2cdeb6928a 117 ad7790.write_filter_reg(filter_val);
adisuciu 0:db2cdeb6928a 118 wait_ms(50);
adisuciu 0:db2cdeb6928a 119 }
adisuciu 0:db2cdeb6928a 120
adisuciu 0:db2cdeb6928a 121 /**
adisuciu 0:db2cdeb6928a 122 * @brief reads the status register of the AD7790
adisuciu 0:db2cdeb6928a 123 * @return status register value
adisuciu 0:db2cdeb6928a 124 */
adisuciu 0:db2cdeb6928a 125 uint8_t CN0357::read_adc_status(void)
adisuciu 0:db2cdeb6928a 126 {
adisuciu 0:db2cdeb6928a 127 return ad7790.read_status_reg();
adisuciu 0:db2cdeb6928a 128 }
adisuciu 0:db2cdeb6928a 129
adisuciu 0:db2cdeb6928a 130 /**
adisuciu 0:db2cdeb6928a 131 * @brief reads the ADC and computes the sensor voltage
adisuciu 0:db2cdeb6928a 132 * @return sensor voltage
adisuciu 0:db2cdeb6928a 133 */
adisuciu 0:db2cdeb6928a 134 float CN0357::read_sensor_voltage(void)
adisuciu 0:db2cdeb6928a 135 {
adisuciu 0:db2cdeb6928a 136 return ad7790.read_voltage();
adisuciu 0:db2cdeb6928a 137 }
adisuciu 0:db2cdeb6928a 138
adisuciu 0:db2cdeb6928a 139 /**
adisuciu 0:db2cdeb6928a 140 * @brief reads the data register of the AD7790
adisuciu 0:db2cdeb6928a 141 * @return data register value
adisuciu 0:db2cdeb6928a 142 */
adisuciu 0:db2cdeb6928a 143 uint16_t CN0357::read_sensor(void)
adisuciu 0:db2cdeb6928a 144 {
adisuciu 0:db2cdeb6928a 145 return ad7790.read_u16();
adisuciu 0:db2cdeb6928a 146 }
adisuciu 0:db2cdeb6928a 147
adisuciu 0:db2cdeb6928a 148 /**
adisuciu 0:db2cdeb6928a 149 * @brief reads and computes the sensor reading in PPM
adisuciu 0:db2cdeb6928a 150 * @return value of the sensor reading in PPM
adisuciu 0:db2cdeb6928a 151 */
adisuciu 0:db2cdeb6928a 152 float CN0357::read_ppm()
adisuciu 0:db2cdeb6928a 153 {
adisuciu 0:db2cdeb6928a 154 return calc_ppm(ad7790.read_voltage()); /* Convert voltage to Gas concentration*/
adisuciu 0:db2cdeb6928a 155 }
adisuciu 0:db2cdeb6928a 156
adisuciu 0:db2cdeb6928a 157 /**
adisuciu 0:db2cdeb6928a 158 * @brief computes a value in PPM from a reading received as a param
adisuciu 0:db2cdeb6928a 159 * @param adcVoltage - voltage to be converted to PPM
adisuciu 0:db2cdeb6928a 160 * @return sensor value in PPM
adisuciu 0:db2cdeb6928a 161 */
adisuciu 0:db2cdeb6928a 162 float CN0357::calc_ppm(float adcVoltage)
adisuciu 0:db2cdeb6928a 163 {
adisuciu 0:db2cdeb6928a 164 float fConcentration = 0;
adisuciu 0:db2cdeb6928a 165 fConcentration = (fabs(adcVoltage) / _RDACvalue) / _sensor_sensitivity;
adisuciu 0:db2cdeb6928a 166 return fConcentration;
adisuciu 0:db2cdeb6928a 167 }
adisuciu 0:db2cdeb6928a 168
adisuciu 0:db2cdeb6928a 169 /**
adisuciu 0:db2cdeb6928a 170 * @brief computes voltage from a 16 bit ADC value received as a parameter
adisuciu 0:db2cdeb6928a 171 * @param data - ADC value
adisuciu 0:db2cdeb6928a 172 * @return sensor voltage
adisuciu 0:db2cdeb6928a 173 */
adisuciu 0:db2cdeb6928a 174 float CN0357::data_to_voltage(uint16_t data)
adisuciu 0:db2cdeb6928a 175 {
adisuciu 0:db2cdeb6928a 176 return ad7790.data_to_voltage(data);
adisuciu 0:db2cdeb6928a 177 }
adisuciu 0:db2cdeb6928a 178
adisuciu 0:db2cdeb6928a 179 /**
adisuciu 0:db2cdeb6928a 180 * @brief sets a new value for the RDAC
adisuciu 0:db2cdeb6928a 181 * @param resistance new value for the resistance
adisuciu 0:db2cdeb6928a 182 * @return none
adisuciu 0:db2cdeb6928a 183 */
adisuciu 0:db2cdeb6928a 184 void CN0357::set_RDAC_value(float resistance)
adisuciu 0:db2cdeb6928a 185 {
adisuciu 0:db2cdeb6928a 186 _RDACvalue = ad5270.write_RDAC(resistance);
adisuciu 0:db2cdeb6928a 187 }
adisuciu 0:db2cdeb6928a 188
adisuciu 0:db2cdeb6928a 189 /**
adisuciu 0:db2cdeb6928a 190 * @brief getter method for RDAC value
adisuciu 0:db2cdeb6928a 191 * @return value of the RDAC in ohms
adisuciu 0:db2cdeb6928a 192 */
adisuciu 0:db2cdeb6928a 193 float CN0357::get_RDAC_value()
adisuciu 0:db2cdeb6928a 194 {
adisuciu 0:db2cdeb6928a 195 return _RDACvalue;
adisuciu 0:db2cdeb6928a 196 }
adisuciu 0:db2cdeb6928a 197
adisuciu 0:db2cdeb6928a 198 /**
adisuciu 0:db2cdeb6928a 199 * @brief set sensor range and sensitivity
adisuciu 0:db2cdeb6928a 200 * sets sensor range, sensitivity
adisuciu 0:db2cdeb6928a 201 * returns suggested resistance value for feedback resistor
adisuciu 0:db2cdeb6928a 202 * @param range - range of the sensor used (in ppm)
adisuciu 0:db2cdeb6928a 203 * @param sensitivity - sensitivity of the sensor (in A/ppm)
adisuciu 0:db2cdeb6928a 204 * @return suggested resistance value for feedback resistor
adisuciu 0:db2cdeb6928a 205 */
adisuciu 0:db2cdeb6928a 206 float CN0357::set_sensor_parameters(float range, float sensitivity)
adisuciu 0:db2cdeb6928a 207 {
adisuciu 0:db2cdeb6928a 208 _sensor_sensitivity = static_cast<float>(sensitivity);
adisuciu 0:db2cdeb6928a 209 _sensor_range = range;
adisuciu 0:db2cdeb6928a 210 return (_vref / (static_cast<float>(_sensor_range * _sensor_sensitivity)));
adisuciu 0:db2cdeb6928a 211 }
adisuciu 0:db2cdeb6928a 212
adisuciu 0:db2cdeb6928a 213 /**
adisuciu 0:db2cdeb6928a 214 * @brief getter method for sensor sensitivity
adisuciu 0:db2cdeb6928a 215 * @return sensor sensitivity (in A/ppm)
adisuciu 0:db2cdeb6928a 216 */
adisuciu 0:db2cdeb6928a 217 float CN0357::get_sensor_sensitivity()
adisuciu 0:db2cdeb6928a 218 {
adisuciu 0:db2cdeb6928a 219 return _sensor_sensitivity;
adisuciu 0:db2cdeb6928a 220 }
adisuciu 0:db2cdeb6928a 221
adisuciu 0:db2cdeb6928a 222 /**
adisuciu 0:db2cdeb6928a 223 * @brief getter method for sensor range
adisuciu 0:db2cdeb6928a 224 * @return sensor range (in ppm)
adisuciu 0:db2cdeb6928a 225 */
adisuciu 0:db2cdeb6928a 226 float CN0357::get_sensor_range()
adisuciu 0:db2cdeb6928a 227 {
adisuciu 0:db2cdeb6928a 228 return _sensor_range;
adisuciu 0:db2cdeb6928a 229 }