API Reference¶

The Arduino library API is implemented via the PASCO2Ino class.

XENSIV™ PAS CO2 Arduino API¶

class PASCO2Ino¶

Public Functions

PASCO2Ino(TwoWire *wire = &Wire, uint8_t intPin = unusedPin)¶

XENSIV™ PAS CO2 I2C Arduino Constructor.

Parameters

wire – [in] TwoWire interface instance. Default is the Arduino primary Wire instance.
intPin – [in] Interrupt pin. Default is UnusedPin

Pre

None

PASCO2Ino(HardwareSerial *serial, uint8_t intPin = unusedPin)¶

XENSIV™ PAS CO2 UART Arduino Constructor.

Parameters

serial – [in] Serial interface instance
intPin – [in] Interrupt pin. Default is UnusedPin

Pre

None

~PASCO2Ino()¶

XENSIV™ PAS CO2 Arduino Destructor.

It disables the sensor and deletes all the dynamically created PAL instances in the constructor

Pre: None

Error_t begin()¶

Begins the sensor.

Initializes the serial interface if the initialization is delegated to the PASCO2 class. Sets the I2C freq or UART baudrate to the default values prior the serial interface initialization. Initializes the interrupt pin if used.

Returns: XENSIV™ PAS CO2 error code
Pre: None
Returns: XENSIV_PASCO2_OK – if success

Error_t end()¶

Ends the sensor.

Deinitializes the serial interface if the deinitialization is delegated to the PASCO2Ino class. Deinitializes the interrupt pin if used.

Returns: XENSIV™ PAS CO2 error code
Pre: begin()
Returns: XENSIV_PASCO2_OK – always

Error_t startMeasure(int16_t periodInSec = 0, int16_t alarmTh = 0, void (*cback)(void*) = nullptr, bool earlyNotification = false)¶

Triggers the internal measuring of the sensor.

The function start the measurement controlling the different sensor modes and features depending on the configured arguments.

Single shot

If the function is called with no arguments, the sensor will be triggered to perform a single shot measurement. The user needs to poll with getCO2() until the CO2 value is available and has been read out from the sensor. The CO2 concentration value read will be zero as long as no value is available or if any error occurred in the readout attempt. Polling example:

PASCO2Ino cotwo(serial_intf); 
int16_t   co2ppm;

serial_intf.begin();

cotwo.begin();              

cotwo.startMeasure();

do{ cotwo.getCO2(co2ppm); } while (co2ppm == 0);  

Continuous measurement

Continuous measurements (periodInSec) will configure the sensor to perform a measurement every desired period. Between 5 and 4095 seconds. Without further arguments, the user has to poll with getCO2() until the value is available. Any super loop or thread routine, can just consists on reading the CO2 (getCO2()). For example, measure every 5 minutes:

PASCO2Ino cotwo(serial_intf);
int16_t   co2ppm;

serial_intf.begin();

cotwo.begin();  

cotwo.startMeasure(300);

while(1)
{
    delay(300000); // Measure will be ready every 5 min

    do{ cotwo.getCO2(co2ppm); } while (co2ppm == 0);  
    // ... do something with the co2 value ... 
}

Synching readouts with the hardware interrupt

In order not to saturate the sensor with constant serial requests, especially in continuous mode, it is recommended to synch the readout with a timer. Or even better using the hardware GPIO hardware interrupt. If the interrupt pin has been provided, passing a callback function will enable the interrupt mode. The type of interrupt is decided depending on the value of the rest of the arguments and operations modes. Some example:

volatile bool intFlag = false;
void cback(void *)
{
    intFlag = true;
}

PASCO2Ino cotwo(serial_intf, interrupt);
int16_t   co2ppm;

serial_intf.begin();

cotwo.begin();  

cotwo.startMeasure(300,0,cback);

while(1)
{
    while(!intFlag) { // block or yield() };
    cotwo.getCO2(co2ppm);   
    // ... do something with the co2 value ... 
    intFlag = false;
}

Alarm mode

If the alarm threshold argument is non-zero, the alarm mode is activated, and the sensor internal flag will be enabled if the concentration of CO2 goes above the specified value. This option is better combined with the interupt mode. Thus, if the interrupt mode is available and a callback function is passed, the interrupt will occurr only when the co2 concentration goes above the threshold. This makes mostly sense for continuous measurement configuration. But it can be used as well for a single shot configuration

Early notification

The early notification mode can be used for battery power solutions. The interrupt signal can trigger the enablement of the 12V emitter power supply just before the measurement is performed, and switch it off as the interrupt signal is disabled. Therefore, the power supply 12V only needs to be on during the CO2 sensing.

When this flag is set, the alarm interrupt functionality is not available. Both options cannot be combined.

Parameters

periodInSec – [in] Enables continuous measurement with the specified period. The default value is 0, meaning single shot operation. The valid period range goes between 5 and 4095 seconds
alarmTh – [in] Enables upper alarm threshold mode for the specified ppm value The default value is 0, meaning no alarm mode. For any non-zero value, the sensor will internally set the alarm flag. If an interrupt callback function is provided, then the interrupt will occurr only when the defined threshold has been tresspassed
cback – [in] Pointer to the callback function to be called upon interrupt
earlyNotification – [in] Enables early notifification interrupt. Disabled (false) by default

Returns

XENSIV™ PAS CO2 error code

Pre

begin()

Returns

XENSIV_PASCO2_OK – if success

Error_t stopMeasure()¶

Stops the internal measuring of the sensor.

Sets operation mode to idle

Returns: XENSIV™ PAS CO2 error code
Pre: begin()
Returns: XENSIV_PASCO2_OK – if success

Error_t getCO2(int16_t &CO2PPM)¶

Gets the CO2 concentration measured.

The value read is zero when no measurement is yet available or an error has ocurrred.

Parameters: co2ppm – [out] CO2 concentration read (in ppm)
Returns: XENSIV™ PAS CO2 error code
Pre: startMeasure()
Returns: XENSIV_PASCO2_OK – if success

Error_t getDiagnosis(Diag_t &diagnosis)¶

Gets diagnosis information.

The sensor status registers includes the following flags:

Sensor ready
PWM pin enabled
Temperature out of range error
IR emitter voltage out of range error
Communication error which will be stored in the Diag_t struct varible passed by argument. After reading the flags, these are cleared in the device writing in the corresponding clear flag bitfields.

Parameters: diagnosis – [out] Struct to store the diagnosis flags values
Returns: XENSIV™ PAS CO2 error code
Pre: None
Returns: XENSIV_PASCO2_OK – if success

Error_t setABOC(ABOC_t aboc, int16_t abocRef)¶

Configures the sensor automatic baseline compensation.

Parameters

aboc – [in] Automatic baseline compenstation mode
abocRef – [in] Automatic baseline compensation reference

Returns

XENSIV™ PAS CO2 error code

Pre

begin()

Returns

XENSIV_PASCO2_OK – if success

Error_t setPressRef(uint16_t pressRef)¶

Sets the sensor pressure reference.

Parameters: pressRef – [in] Pressure reference value. Min value is 750, and max 1150.
Returns: XENSIV™ PAS CO2 error code
Pre: begin()
Returns: XENSIV_PASCO2_OK – if success

Error_t performForcedCompensation(uint16_t co2Ref)¶

Performs force compensation.

Calculates the offset compensation when the sensor is exposed to a CO2 reference value.

Warning

The device is left in idle mode after the compensation value is stored in non-volatile memory.

Parameters: co2Ref – [in] Automatic baseline compenstation mode
Returns: XENSIV™ PAS CO2 error code
Pre: begin()
Returns: XENSIV_PASCO2_OK – if success

Error_t clearForcedCompensation()¶

Resets the forced calibration correction factor.

Returns: XENSIV™ PAS CO2 error code
Pre: begin()
Returns: XENSIV_PASCO2_OK – if success

Error_t reset()¶

Resets the sensor via serial command.

Returns: XENSIV™ PAS CO2 error code
Pre: begin()
Returns: XENSIV_PASCO2_OK – if success

Error_t getDeviceID(uint8_t &prodID, uint8_t &revID)¶

Gets device product identifier.

Parameters

prodID – [out] Product identifier
revID – [out] Version identifier

Returns

XENSIV™ PAS CO2 error code

Pre

begin()

Returns

XENSIV_PASCO2_OK – if success

Error_t getRegister(uint8_t regAddr, uint8_t *data, uint8_t len)¶

Reads from the sensor device into the given data buffer.

Parameters

regAddr – [in] Start register address
data – [out] Pointer to the data buffer to store the register values of the sensor
len – [in] Number of bytes of data to be read

Returns

XENSIV™ PAS CO2 error code

Pre

begin()

Returns

XENSIV_PASCO2_OK – if success

Error_t setRegister(uint8_t regAddr, const uint8_t *data, uint8_t len)¶

Writes the given data buffer into the sensor device.

Parameters

regAddr – [in] Start register address
data – [in] Pointer to the data buffer to be written in the sensor
len – [in] Number of bytes of data to be written

Returns

XENSIV™ PAS CO2 error code

Pre

begin()

Returns

XENSIV_PASCO2_OK – if success

Public Static Attributes

static constexpr uint8_t unusedPin = 0xFFU¶: Unused pin

Types¶

Return Error Codes¶

typedef int32_t Error_t¶

XENSIV_PASCO2_OK¶: Result code indicating a successful operation

XENSIV_PASCO2_ERR_COMM¶: Result code indicating a communication error

XENSIV_PASCO2_ERR_WRITE_TOO_LARGE¶: Result code indicating that an unexpectedly large I2C write was requested which is not supported

XENSIV_PASCO2_ERR_NOT_READY¶: Result code indicating that the sensor is not yet ready after reset

XENSIV_PASCO2_ICCERR¶: Result code indicating whether a non-valid command has been received by the serial communication interface

XENSIV_PASCO2_ORVS¶: Result code indicating whether a condition where VDD12V has been outside the specified valid range has been detected

XENSIV_PASCO2_ORTMP¶: Result code indicating whether a condition where the temperature has been outside the specified valid range has been detected

XENSIV_PASCO2_READ_NRDY¶: Result code indicating that a new CO2 value is not yet ready

Dignosis¶

typedef xensiv_pasco2_status_t Diag_t¶

union xensiv_pasco2_status_t¶

#include <xensiv_pasco2.h>

Structure of the sensor’s status register (SENS_STS)

Public Members

uint32_t __pad0__¶

uint32_t iccerr¶: Communication error notification bit. Indicates whether an invalid command has been received by the serial communication interface

uint32_t orvs¶: Out-of-range VDD12V error bit

uint32_t ortmp¶: Out-of-range temperature error bit

uint32_t pwm_dis_st¶: PWM_DIS pin status

uint32_t sen_rdy¶: Sensor ready bit

struct xensiv_pasco2_status_t::[anonymous] b¶: Structure used for bit access

uint8_t u¶: Type used for byte access

Baseline Offset Compensation¶

typedef xensiv_pasco2_boc_cfg_t ABOC_t¶

enum xensiv_pasco2_boc_cfg_t¶

Enum defining the different device baseline offset compensation (BOC) modes

Values:

enumerator XENSIV_PASCO2_BOC_CFG_DISABLE¶: No offset compensation occurs

enumerator XENSIV_PASCO2_BOC_CFG_AUTOMATIC¶: The offset is periodically updated at each BOC computation

enumerator XENSIV_PASCO2_BOC_CFG_FORCED¶: Forced compensation

XENSIV™ PAS CO2 C Reference API¶

The Arduino library is wrapping the platform abstracted C library from this project. Find out the complete C core library documentation here.