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

Files at this revision

API Documentation at this revision

Comitter:
adisuciu
Date:
Wed May 18 15:18:49 2016 +0000
Child:
1:19e1bf69dc75
Commit message:
Initial revision

Changed in this revision

CN0357.cpp Show annotated file Show diff for this revision Revisions of this file
CN0357.h Show annotated file Show diff for this revision Revisions of this file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/CN0357.cpp	Wed May 18 15:18:49 2016 +0000
@@ -0,0 +1,229 @@
+/**
+*   @file     cn0357.cpp
+*   @brief    Source file for CN0357
+*   @author   Analog Devices Inc.
+*
+* For support please go to:
+* Github: https://github.com/analogdevicesinc/mbed-adi
+* Support: https://ez.analog.com/community/linux-device-drivers/microcontroller-no-os-drivers
+* Product: www.analog.com/EVAL-CN0357-ARDZ
+* More: https://wiki.analog.com/resources/tools-software/mbed-drivers-all
+
+********************************************************************************
+* Copyright 2016(c) Analog Devices, Inc.
+*
+* All rights reserved.
+*
+* Redistribution and use in source and binary forms, with or without
+* modification, are permitted provided that the following conditions are met:
+*  - Redistributions of source code must retain the above copyright
+*    notice, this list of conditions and the following disclaimer.
+*  - Redistributions in binary form must reproduce the above copyright
+*    notice, this list of conditions and the following disclaimer in
+*    the documentation and/or other materials provided with the
+*    distribution.
+*  - Neither the name of Analog Devices, Inc. nor the names of its
+*    contributors may be used to endorse or promote products derived
+*    from this software without specific prior written permission.
+*  - The use of this software may or may not infringe the patent rights
+*    of one or more patent holders.  This license does not release you
+*    from the requirement that you obtain separate licenses from these
+*    patent holders to use this software.
+*  - Use of the software either in source or binary form, must be run
+*    on or directly connected to an Analog Devices Inc. component.
+*
+* THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES "AS IS" AND ANY EXPRESS OR
+* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, NON-INFRINGEMENT,
+* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+* IN NO EVENT SHALL ANALOG DEVICES BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+* LIMITED TO, INTELLECTUAL PROPERTY RIGHTS, PROCUREMENT OF SUBSTITUTE GOODS OR
+* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+********************************************************************************/
+
+#include "mbed.h"
+#include "AD7790.h"
+#include "AD5270.h"
+#include "CN0357.h"
+
+/**
+ * @brief CN0357 constructor
+ * @param CSAD7790 - (optional)chip select of the AD7790
+ * @param CSAD5270 - (optional)chip select of the AD5270
+ * @param MOSI - (optional)pin of the SPI interface
+ * @param MISO - (optional)pin of the SPI interface
+ * @param SCK  - (optional)pin of the SPI interface
+ */
+CN0357::CN0357(PinName CSAD7790, PinName CSAD5270, PinName MOSI, PinName MISO,
+               PinName SCK) :
+    _vref(1.2), _sensor_sensitivity(0), _sensor_range(0), _RDACvalue(0),
+    ad7790(_vref, CSAD7790, MOSI, MISO, SCK), ad5270(CSAD5270, 20000.0, MOSI, MISO, SCK)
+
+{
+}
+
+/**
+ * @brief initializes the AD7790 and the AD5270
+ * @param range - range of the sensor used (in ppm)
+ * @param sensitivity - sensitivity of the sensor (A/ppm)
+ * @param jp - (optional)jumper configuration of the CN0357
+ * @param mode_val - (optional)if jp is set to InternalADC, configures the mode register of the Internal ADC
+ * @param filter_val - (optional)if jp is set to InternalADC, configures the filter register of the Internal ADC
+ */
+void CN0357::init(float range, float sensitivity, JumperConfig_t jp, uint8_t mode_val, uint8_t filter_val)
+{
+    ad5270.frequency(500000);
+    ad7790.frequency(500000);
+
+    float resistance = set_sensor_parameters(range, sensitivity);
+
+    if(jp == INTERNAL_AD7790) {
+        _AD7790_init(mode_val, filter_val);
+    }
+    _rdac_init(resistance);
+}
+
+/**
+ * @brief initializes the RDAC and sets SDO to HiZ
+ * @param resistance - resistance value to initialize the RDAC
+ * @return
+ */
+void CN0357::_rdac_init(float resistance)
+{
+    /* RDAC initialization*/
+    /* Compute for the nearest RDAC value from given resistance and save data to the structure */
+    set_RDAC_value(resistance);
+    /* Set AD5270 SDO to Hi-Z */
+    ad5270.set_SDO_HiZ();
+}
+
+/**
+ * @brief initializes the AD7790
+ * @param mode_val -  configures the mode register of the Internal ADC
+ * @param filter_val -  configures the filter register of the Internal ADC
+ */
+void CN0357::_AD7790_init(uint8_t mode_val, uint8_t filter_val)
+{
+    ad7790.reset();
+    wait_ms(50);
+
+    ad7790.write_mode_reg(mode_val);
+    wait_us(2);
+
+    ad7790.write_filter_reg(filter_val);
+    wait_ms(50);
+}
+
+/**
+ * @brief reads the status register of the AD7790
+ * @return status register value
+ */
+uint8_t CN0357::read_adc_status(void)
+{
+    return ad7790.read_status_reg();
+}
+
+/**
+ * @brief reads the ADC and computes the sensor voltage
+ * @return sensor voltage
+ */
+float CN0357::read_sensor_voltage(void)
+{
+    return ad7790.read_voltage();
+}
+
+/**
+ * @brief reads the data register of the AD7790
+ * @return data register value
+ */
+uint16_t CN0357::read_sensor(void)
+{
+    return ad7790.read_u16();
+}
+
+/**
+ * @brief reads and computes the sensor reading in PPM
+ * @return value of the sensor reading in PPM
+ */
+float CN0357::read_ppm()
+{
+    return calc_ppm(ad7790.read_voltage()); /* Convert voltage to Gas concentration*/
+}
+
+/**
+ * @brief computes a value in PPM from a reading received as a param
+ * @param adcVoltage - voltage to be converted to PPM
+ * @return sensor value in PPM
+ */
+float CN0357::calc_ppm(float adcVoltage)
+{
+    float fConcentration = 0;
+    fConcentration = (fabs(adcVoltage) / _RDACvalue) / _sensor_sensitivity;
+    return fConcentration;
+}
+
+/**
+ * @brief computes voltage from a 16 bit ADC value received as a parameter
+ * @param data - ADC value
+ * @return sensor voltage
+ */
+float CN0357::data_to_voltage(uint16_t data)
+{
+    return ad7790.data_to_voltage(data);
+}
+
+/**
+ * @brief sets a new value for the RDAC
+ * @param resistance new value for the resistance
+ * @return none
+ */
+void CN0357::set_RDAC_value(float resistance)
+{
+    _RDACvalue = ad5270.write_RDAC(resistance);
+}
+
+/**
+ * @brief getter method for RDAC value
+ * @return value of the RDAC in ohms
+ */
+float CN0357::get_RDAC_value()
+{
+    return _RDACvalue;
+}
+
+/**
+ * @brief set sensor range and sensitivity
+ * sets sensor range, sensitivity
+ * returns suggested resistance value for feedback resistor
+ * @param range - range of the sensor used (in ppm)
+ * @param sensitivity - sensitivity of the sensor (in A/ppm)
+ * @return suggested resistance value for feedback resistor
+ */
+float CN0357::set_sensor_parameters(float range, float sensitivity)
+{
+    _sensor_sensitivity = static_cast<float>(sensitivity);
+    _sensor_range = range;
+    return (_vref / (static_cast<float>(_sensor_range * _sensor_sensitivity)));
+}
+
+/**
+ * @brief getter method for sensor sensitivity
+ * @return sensor sensitivity (in A/ppm)
+ */
+float CN0357::get_sensor_sensitivity()
+{
+    return _sensor_sensitivity;
+}
+
+/**
+ * @brief getter method for sensor range
+ * @return sensor range (in ppm)
+ */
+float CN0357::get_sensor_range()
+{
+    return _sensor_range;
+}
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/CN0357.h	Wed May 18 15:18:49 2016 +0000
@@ -0,0 +1,102 @@
+/**
+*   @file     cn0357.h
+*   @brief    Header file for CN0357
+*   @author   Analog Devices Inc.
+*
+* For support please go to:
+* Github: https://github.com/analogdevicesinc/mbed-adi
+* Support: https://ez.analog.com/community/linux-device-drivers/microcontroller-no-os-drivers
+* Product: www.analog.com/EVAL-CN0357-ARDZ
+* More: https://wiki.analog.com/resources/tools-software/mbed-drivers-all
+
+********************************************************************************
+* Copyright 2016(c) Analog Devices, Inc.
+*
+* All rights reserved.
+*
+* Redistribution and use in source and binary forms, with or without
+* modification, are permitted provided that the following conditions are met:
+*  - Redistributions of source code must retain the above copyright
+*    notice, this list of conditions and the following disclaimer.
+*  - Redistributions in binary form must reproduce the above copyright
+*    notice, this list of conditions and the following disclaimer in
+*    the documentation and/or other materials provided with the
+*    distribution.
+*  - Neither the name of Analog Devices, Inc. nor the names of its
+*    contributors may be used to endorse or promote products derived
+*    from this software without specific prior written permission.
+*  - The use of this software may or may not infringe the patent rights
+*    of one or more patent holders.  This license does not release you
+*    from the requirement that you obtain separate licenses from these
+*    patent holders to use this software.
+*  - Use of the software either in source or binary form, must be run
+*    on or directly connected to an Analog Devices Inc. component.
+*
+* THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES "AS IS" AND ANY EXPRESS OR
+* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, NON-INFRINGEMENT,
+* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+* IN NO EVENT SHALL ANALOG DEVICES BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+* LIMITED TO, INTELLECTUAL PROPERTY RIGHTS, PROCUREMENT OF SUBSTITUTE GOODS OR
+* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+********************************************************************************/
+
+#ifndef CN0357_H
+#define CN0357_H
+
+#include "mbed.h"
+#include "AD7790.h"
+#include "AD5270.h"
+
+/**
+ * @brief EVAL-CN0357 toxic gas sensor shield
+ */
+class CN0357
+{
+public:
+
+private:
+    float _vref;
+    float _sensor_sensitivity;
+    float _sensor_range;
+    float _RDACvalue;
+public:
+    AD7790 ad7790; ///< AD7790 instance - can be used for manual overriding
+    AD5270 ad5270; ///< AD5270 instance - can be used for manual overriding
+
+    /// CN0357 shield jumper configuration
+    typedef enum {
+        INTERNAL_AD7790 = 0, 	///< The shield's AD7790 is used
+        EXTERNAL_ADC			///< Sensor analog output is routed to A1 pin of the shield
+    } JumperConfig_t;
+
+    CN0357(PinName CSAD7790 = D8, PinName CSAD5270 = D6, PinName MOSI = SPI_MOSI, PinName MISO = SPI_MISO, PinName SCK = SPI_SCK);
+    void init(float range, float sensitivity, JumperConfig_t jp = INTERNAL_AD7790, uint8_t mode_val = _DEFAULT_MODE_VAL, uint8_t filter_val = _DEFAULT_FILTER_VAL);
+
+    uint8_t  read_adc_status(void);
+    uint16_t read_sensor(void);
+    float read_sensor_voltage(void);
+    float data_to_voltage(uint16_t data);
+    float calc_ppm(float adcVoltage);
+    float read_ppm(void);
+
+    void  set_RDAC_value(float resistor_val);
+    float get_RDAC_value(void);
+    float set_sensor_parameters(float range, float sensitivity);
+    float get_sensor_range(void);
+    float get_sensor_sensitivity(void);
+
+private:
+    const static int _RESET = 0xff;
+    const static int _DEFAULT_MODE_VAL = AD7790::MD1 | AD7790::MD0; // POWERDOWN MODE
+    const static int _DEFAULT_FILTER_VAL = AD7790::FS0 | AD7790::FS1 | AD7790::FS2;
+    void _rdac_init(float resistanceValue);
+    void _AD7790_init(uint8_t mode_val, uint8_t filter_val);
+
+};
+
+#endif // CN0357_H