C/C++ - CO2 Bricklet 2.0

This is the description of the C/C++ API bindings for the CO2 Bricklet 2.0. General information and technical specifications for the CO2 Bricklet 2.0 are summarized in its hardware description.

An installation guide for the C/C++ API bindings is part of their general description.

Examples

The example code below is Public Domain (CC0 1.0).

Simple

Download (example_simple.c)

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#include <stdio.h>

#include "ip_connection.h"
#include "bricklet_co2_v2.h"

#define HOST "localhost"
#define PORT 4223
#define UID "XYZ" // Change XYZ to the UID of your CO2 Bricklet 2.0

int main(void) {
    // Create IP connection
    IPConnection ipcon;
    ipcon_create(&ipcon);

    // Create device object
    CO2V2 co2;
    co2_v2_create(&co2, UID, &ipcon);

    // Connect to brickd
    if(ipcon_connect(&ipcon, HOST, PORT) < 0) {
        fprintf(stderr, "Could not connect\n");
        return 1;
    }
    // Don't use device before ipcon is connected

    // Get current all values
    uint16_t co2_concentration, humidity; int16_t temperature;
    if(co2_v2_get_all_values(&co2, &co2_concentration, &temperature, &humidity) < 0) {
        fprintf(stderr, "Could not get all values, probably timeout\n");
        return 1;
    }

    printf("CO2 Concentration: %u ppm\n", co2_concentration);
    printf("Temperature: %f °C\n", temperature/100.0);
    printf("Humidity: %f %%RH\n", humidity/100.0);

    printf("Press key to exit\n");
    getchar();
    co2_v2_destroy(&co2);
    ipcon_destroy(&ipcon); // Calls ipcon_disconnect internally
    return 0;
}

Callback

Download (example_callback.c)

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#include <stdio.h>

#include "ip_connection.h"
#include "bricklet_co2_v2.h"

#define HOST "localhost"
#define PORT 4223
#define UID "XYZ" // Change XYZ to the UID of your CO2 Bricklet 2.0

// Callback function for all values callback
void cb_all_values(uint16_t co2_concentration, int16_t temperature, uint16_t humidity,
                   void *user_data) {
    (void)user_data; // avoid unused parameter warning

    printf("CO2 Concentration: %u ppm\n", co2_concentration);
    printf("Temperature: %f °C\n", temperature/100.0);
    printf("Humidity: %f %%RH\n", humidity/100.0);
    printf("\n");
}

int main(void) {
    // Create IP connection
    IPConnection ipcon;
    ipcon_create(&ipcon);

    // Create device object
    CO2V2 co2;
    co2_v2_create(&co2, UID, &ipcon);

    // Connect to brickd
    if(ipcon_connect(&ipcon, HOST, PORT) < 0) {
        fprintf(stderr, "Could not connect\n");
        return 1;
    }
    // Don't use device before ipcon is connected

    // Register all values callback to function cb_all_values
    co2_v2_register_callback(&co2,
                             CO2_V2_CALLBACK_ALL_VALUES,
                             (void *)cb_all_values,
                             NULL);

    // Set period for all values callback to 1s (1000ms)
    co2_v2_set_all_values_callback_configuration(&co2, 1000, false);

    printf("Press key to exit\n");
    getchar();
    co2_v2_destroy(&co2);
    ipcon_destroy(&ipcon); // Calls ipcon_disconnect internally
    return 0;
}

API

Every function of the C/C++ bindings returns an integer which describes an error code. Data returned from the device, when a getter is called, is handled via call by reference. These parameters are labeled with the ret_ prefix.

Possible error codes are:

  • E_OK = 0
  • E_TIMEOUT = -1
  • E_NO_STREAM_SOCKET = -2
  • E_HOSTNAME_INVALID = -3
  • E_NO_CONNECT = -4
  • E_NO_THREAD = -5
  • E_NOT_ADDED = -6 (unused since bindings version 2.0.0)
  • E_ALREADY_CONNECTED = -7
  • E_NOT_CONNECTED = -8
  • E_INVALID_PARAMETER = -9
  • E_NOT_SUPPORTED = -10
  • E_UNKNOWN_ERROR_CODE = -11
  • E_STREAM_OUT_OF_SYNC = -12
  • E_INVALID_UID = -13

as defined in ip_connection.h.

All functions listed below are thread-safe.

Basic Functions

void co2_v2_create(CO2V2 *co2_v2, const char *uid, IPConnection *ipcon)

Creates the device object co2_v2 with the unique device ID uid and adds it to the IPConnection ipcon:

CO2V2 co2_v2;
co2_v2_create(&co2_v2, "YOUR_DEVICE_UID", &ipcon);

This device object can be used after the IP connection has been connected (see examples above).

void co2_v2_destroy(CO2V2 *co2_v2)

Removes the device object co2_v2 from its IPConnection and destroys it. The device object cannot be used anymore afterwards.

int co2_v2_get_all_values(CO2V2 *co2_v2, uint16_t *ret_co2_concentration, int16_t *ret_temperature, uint16_t *ret_humidity)

Returns all values measured by the CO2 Bricklet 2.0. The values are CO2 concentration (in ppm), temperature (in 0.01 °C) and humidity (in 0.01 %RH).

If you want to get the values periodically, it is recommended to use the CO2_V2_CALLBACK_ALL_VALUES callback. You can set the callback configuration with co2_v2_set_all_values_callback_configuration().

int co2_v2_set_air_pressure(CO2V2 *co2_v2, uint16_t air_pressure)

The CO2 concentration (among other things) depends on the ambient air pressure.

To increase the accuracy of the CO2 Bricklet 2.0 you can set the current air pressure. You use the Barometer Bricklet 2.0 or the Air Quality Bricklet to get the current air pressure.

The expected unit of the ambient air pressure value is mbar.

By default air pressure compensation is disabled. Once you set a value it will be used for compensation. You can turn the compensation off again by setting the value to 0.

It is sufficient to update the value every few minutes.

int co2_v2_get_air_pressure(CO2V2 *co2_v2, uint16_t *ret_air_pressure)

Returns the ambient air pressure as set by co2_v2_set_air_pressure().

int co2_v2_set_temperature_offset(CO2V2 *co2_v2, uint16_t offset)

Sets a temperature offset with resolution 1/100°C. A offset of 10 will decrease the measured temperature by 0.1°C.

If you install this Bricklet into an enclosure and you want to measure the ambient temperature, you may have to decrease the measured temperature by some value to compensate for the error because of the heating inside of the enclosure.

We recommend that you leave the parts in the enclosure running for at least 24 hours such that a temperature equilibrium can be reached. After that you can measure the temperature directly outside of enclosure and set the difference as offset.

This temperature offset is used to calculate the relative humidity and CO2 concentration. In case the Bricklet is installed in an enclosure, we recommend to measure and set the temperature offset to improve the accuracy of the measurements.

It is sufficient to set the temperature offset once. The offset is saved in non-volatile memory and is applied again after a power loss.

int co2_v2_get_temperature_offset(CO2V2 *co2_v2, uint16_t *ret_offset)

Returns the temperature offset as set by co2_v2_set_temperature_offset().

int co2_v2_get_co2_concentration(CO2V2 *co2_v2, uint16_t *ret_co2_concentration)

Returns CO2 concentration in ppm.

If you want to get the value periodically, it is recommended to use the CO2_V2_CALLBACK_CO2_CONCENTRATION callback. You can set the callback configuration with co2_v2_set_co2_concentration_callback_configuration().

int co2_v2_get_temperature(CO2V2 *co2_v2, int16_t *ret_temperature)

Returns temperature in steps of 0.01 °C.

If you want to get the value periodically, it is recommended to use the CO2_V2_CALLBACK_TEMPERATURE callback. You can set the callback configuration with co2_v2_set_temperature_callback_configuration().

int co2_v2_get_humidity(CO2V2 *co2_v2, uint16_t *ret_humidity)

Returns relative humidity in steps of 0.01 %RH.

If you want to get the value periodically, it is recommended to use the CO2_V2_CALLBACK_HUMIDITY callback. You can set the callback configuration with co2_v2_set_humidity_callback_configuration().

Advanced Functions

int co2_v2_get_api_version(CO2V2 *co2_v2, uint8_t ret_api_version[3])

Returns the version of the API definition (major, minor, revision) implemented by this API bindings. This is neither the release version of this API bindings nor does it tell you anything about the represented Brick or Bricklet.

int co2_v2_get_response_expected(CO2V2 *co2_v2, uint8_t function_id, bool *ret_response_expected)

Returns the response expected flag for the function specified by the function ID parameter. It is true if the function is expected to send a response, false otherwise.

For getter functions this is enabled by default and cannot be disabled, because those functions will always send a response. For callback configuration functions it is enabled by default too, but can be disabled by co2_v2_set_response_expected(). For setter functions it is disabled by default and can be enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

See co2_v2_set_response_expected() for the list of function ID defines available for this function.

int co2_v2_set_response_expected(CO2V2 *co2_v2, uint8_t function_id, bool response_expected)

Changes the response expected flag of the function specified by the function ID parameter. This flag can only be changed for setter (default value: false) and callback configuration functions (default value: true). For getter functions it is always enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

The following function ID defines are available for this function:

  • CO2_V2_FUNCTION_SET_AIR_PRESSURE = 2
  • CO2_V2_FUNCTION_SET_TEMPERATURE_OFFSET = 4
  • CO2_V2_FUNCTION_SET_ALL_VALUES_CALLBACK_CONFIGURATION = 6
  • CO2_V2_FUNCTION_SET_CO2_CONCENTRATION_CALLBACK_CONFIGURATION = 10
  • CO2_V2_FUNCTION_SET_TEMPERATURE_CALLBACK_CONFIGURATION = 14
  • CO2_V2_FUNCTION_SET_HUMIDITY_CALLBACK_CONFIGURATION = 18
  • CO2_V2_FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • CO2_V2_FUNCTION_SET_STATUS_LED_CONFIG = 239
  • CO2_V2_FUNCTION_RESET = 243
  • CO2_V2_FUNCTION_WRITE_UID = 248
int co2_v2_set_response_expected_all(CO2V2 *co2_v2, bool response_expected)

Changes the response expected flag for all setter and callback configuration functions of this device at once.

int co2_v2_get_spitfp_error_count(CO2V2 *co2_v2, uint32_t *ret_error_count_ack_checksum, uint32_t *ret_error_count_message_checksum, uint32_t *ret_error_count_frame, uint32_t *ret_error_count_overflow)

Returns the error count for the communication between Brick and Bricklet.

The errors are divided into

  • ACK checksum errors,
  • message checksum errors,
  • framing errors and
  • overflow errors.

The errors counts are for errors that occur on the Bricklet side. All Bricks have a similar function that returns the errors on the Brick side.

int co2_v2_set_bootloader_mode(CO2V2 *co2_v2, uint8_t mode, uint8_t *ret_status)

Sets the bootloader mode and returns the status after the requested mode change was instigated.

You can change from bootloader mode to firmware mode and vice versa. A change from bootloader mode to firmware mode will only take place if the entry function, device identifier and CRC are present and correct.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

The following defines are available for this function:

  • CO2_V2_BOOTLOADER_MODE_BOOTLOADER = 0
  • CO2_V2_BOOTLOADER_MODE_FIRMWARE = 1
  • CO2_V2_BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • CO2_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • CO2_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
  • CO2_V2_BOOTLOADER_STATUS_OK = 0
  • CO2_V2_BOOTLOADER_STATUS_INVALID_MODE = 1
  • CO2_V2_BOOTLOADER_STATUS_NO_CHANGE = 2
  • CO2_V2_BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
  • CO2_V2_BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
  • CO2_V2_BOOTLOADER_STATUS_CRC_MISMATCH = 5
int co2_v2_get_bootloader_mode(CO2V2 *co2_v2, uint8_t *ret_mode)

Returns the current bootloader mode, see co2_v2_set_bootloader_mode().

The following defines are available for this function:

  • CO2_V2_BOOTLOADER_MODE_BOOTLOADER = 0
  • CO2_V2_BOOTLOADER_MODE_FIRMWARE = 1
  • CO2_V2_BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • CO2_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • CO2_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
int co2_v2_set_write_firmware_pointer(CO2V2 *co2_v2, uint32_t pointer)

Sets the firmware pointer for co2_v2_write_firmware(). The pointer has to be increased by chunks of size 64. The data is written to flash every 4 chunks (which equals to one page of size 256).

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

int co2_v2_write_firmware(CO2V2 *co2_v2, uint8_t data[64], uint8_t *ret_status)

Writes 64 Bytes of firmware at the position as written by co2_v2_set_write_firmware_pointer() before. The firmware is written to flash every 4 chunks.

You can only write firmware in bootloader mode.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

int co2_v2_set_status_led_config(CO2V2 *co2_v2, uint8_t config)

Sets the status LED configuration. By default the LED shows communication traffic between Brick and Bricklet, it flickers once for every 10 received data packets.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is will show heartbeat by default.

The following defines are available for this function:

  • CO2_V2_STATUS_LED_CONFIG_OFF = 0
  • CO2_V2_STATUS_LED_CONFIG_ON = 1
  • CO2_V2_STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • CO2_V2_STATUS_LED_CONFIG_SHOW_STATUS = 3
int co2_v2_get_status_led_config(CO2V2 *co2_v2, uint8_t *ret_config)

Returns the configuration as set by co2_v2_set_status_led_config()

The following defines are available for this function:

  • CO2_V2_STATUS_LED_CONFIG_OFF = 0
  • CO2_V2_STATUS_LED_CONFIG_ON = 1
  • CO2_V2_STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • CO2_V2_STATUS_LED_CONFIG_SHOW_STATUS = 3
int co2_v2_get_chip_temperature(CO2V2 *co2_v2, int16_t *ret_temperature)

Returns the temperature in °C as measured inside the microcontroller. The value returned is not the ambient temperature!

The temperature is only proportional to the real temperature and it has bad accuracy. Practically it is only useful as an indicator for temperature changes.

int co2_v2_reset(CO2V2 *co2_v2)

Calling this function will reset the Bricklet. All configurations will be lost.

After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!

int co2_v2_write_uid(CO2V2 *co2_v2, uint32_t uid)

Writes a new UID into flash. If you want to set a new UID you have to decode the Base58 encoded UID string into an integer first.

We recommend that you use Brick Viewer to change the UID.

int co2_v2_read_uid(CO2V2 *co2_v2, uint32_t *ret_uid)

Returns the current UID as an integer. Encode as Base58 to get the usual string version.

int co2_v2_get_identity(CO2V2 *co2_v2, char ret_uid[8], char ret_connected_uid[8], char *ret_position, uint8_t ret_hardware_version[3], uint8_t ret_firmware_version[3], uint16_t *ret_device_identifier)

Returns the UID, the UID where the Bricklet is connected to, the position, the hardware and firmware version as well as the device identifier.

The position can be 'a', 'b', 'c' or 'd'.

The device identifier numbers can be found here. There is also a constant for the device identifier of this Bricklet.

Callback Configuration Functions

void co2_v2_register_callback(CO2V2 *co2_v2, int16_t callback_id, void *function, void *user_data)

Registers the given function with the given callback_id. The user_data will be passed as the last parameter to the function.

The available callback IDs with corresponding function signatures are listed below.

int co2_v2_set_all_values_callback_configuration(CO2V2 *co2_v2, uint32_t period, bool value_has_to_change)

The period in ms is the period with which the CO2_V2_CALLBACK_ALL_VALUES callback is triggered periodically. A value of 0 turns the callback off.

If the value has to change-parameter is set to true, the callback is only triggered after at least one of the values has changed. If the values didn't change within the period, the callback is triggered immediately on change.

If it is set to false, the callback is continuously triggered with the period, independent of the value.

The default value is (0, false).

int co2_v2_get_all_values_callback_configuration(CO2V2 *co2_v2, uint32_t *ret_period, bool *ret_value_has_to_change)

Returns the callback configuration as set by co2_v2_set_all_values_callback_configuration().

int co2_v2_set_co2_concentration_callback_configuration(CO2V2 *co2_v2, uint32_t period, bool value_has_to_change, char option, uint16_t min, uint16_t max)

The period in ms is the period with which the CO2_V2_CALLBACK_CO2_CONCENTRATION callback is triggered periodically. A value of 0 turns the callback off.

If the value has to change-parameter is set to true, the callback is only triggered after the value has changed. If the value didn't change within the period, the callback is triggered immediately on change.

If it is set to false, the callback is continuously triggered with the period, independent of the value.

It is furthermore possible to constrain the callback with thresholds.

The option-parameter together with min/max sets a threshold for the CO2_V2_CALLBACK_CO2_CONCENTRATION callback.

The following options are possible:

Option Description
'x' Threshold is turned off
'o' Threshold is triggered when the value is outside the min and max values
'i' Threshold is triggered when the value is inside or equal to the min and max values
'<' Threshold is triggered when the value is smaller than the min value (max is ignored)
'>' Threshold is triggered when the value is greater than the min value (max is ignored)

If the option is set to 'x' (threshold turned off) the callback is triggered with the fixed period.

The default value is (0, false, 'x', 0, 0).

The following defines are available for this function:

  • CO2_V2_THRESHOLD_OPTION_OFF = 'x'
  • CO2_V2_THRESHOLD_OPTION_OUTSIDE = 'o'
  • CO2_V2_THRESHOLD_OPTION_INSIDE = 'i'
  • CO2_V2_THRESHOLD_OPTION_SMALLER = '<'
  • CO2_V2_THRESHOLD_OPTION_GREATER = '>'
int co2_v2_get_co2_concentration_callback_configuration(CO2V2 *co2_v2, uint32_t *ret_period, bool *ret_value_has_to_change, char *ret_option, uint16_t *ret_min, uint16_t *ret_max)

Returns the callback configuration as set by co2_v2_set_co2_concentration_callback_configuration().

The following defines are available for this function:

  • CO2_V2_THRESHOLD_OPTION_OFF = 'x'
  • CO2_V2_THRESHOLD_OPTION_OUTSIDE = 'o'
  • CO2_V2_THRESHOLD_OPTION_INSIDE = 'i'
  • CO2_V2_THRESHOLD_OPTION_SMALLER = '<'
  • CO2_V2_THRESHOLD_OPTION_GREATER = '>'
int co2_v2_set_temperature_callback_configuration(CO2V2 *co2_v2, uint32_t period, bool value_has_to_change, char option, int16_t min, int16_t max)

The period in ms is the period with which the CO2_V2_CALLBACK_TEMPERATURE callback is triggered periodically. A value of 0 turns the callback off.

If the value has to change-parameter is set to true, the callback is only triggered after the value has changed. If the value didn't change within the period, the callback is triggered immediately on change.

If it is set to false, the callback is continuously triggered with the period, independent of the value.

It is furthermore possible to constrain the callback with thresholds.

The option-parameter together with min/max sets a threshold for the CO2_V2_CALLBACK_TEMPERATURE callback.

The following options are possible:

Option Description
'x' Threshold is turned off
'o' Threshold is triggered when the value is outside the min and max values
'i' Threshold is triggered when the value is inside or equal to the min and max values
'<' Threshold is triggered when the value is smaller than the min value (max is ignored)
'>' Threshold is triggered when the value is greater than the min value (max is ignored)

If the option is set to 'x' (threshold turned off) the callback is triggered with the fixed period.

The default value is (0, false, 'x', 0, 0).

The following defines are available for this function:

  • CO2_V2_THRESHOLD_OPTION_OFF = 'x'
  • CO2_V2_THRESHOLD_OPTION_OUTSIDE = 'o'
  • CO2_V2_THRESHOLD_OPTION_INSIDE = 'i'
  • CO2_V2_THRESHOLD_OPTION_SMALLER = '<'
  • CO2_V2_THRESHOLD_OPTION_GREATER = '>'
int co2_v2_get_temperature_callback_configuration(CO2V2 *co2_v2, uint32_t *ret_period, bool *ret_value_has_to_change, char *ret_option, int16_t *ret_min, int16_t *ret_max)

Returns the callback configuration as set by co2_v2_set_temperature_callback_configuration().

The following defines are available for this function:

  • CO2_V2_THRESHOLD_OPTION_OFF = 'x'
  • CO2_V2_THRESHOLD_OPTION_OUTSIDE = 'o'
  • CO2_V2_THRESHOLD_OPTION_INSIDE = 'i'
  • CO2_V2_THRESHOLD_OPTION_SMALLER = '<'
  • CO2_V2_THRESHOLD_OPTION_GREATER = '>'
int co2_v2_set_humidity_callback_configuration(CO2V2 *co2_v2, uint32_t period, bool value_has_to_change, char option, uint16_t min, uint16_t max)

The period in ms is the period with which the CO2_V2_CALLBACK_HUMIDITY callback is triggered periodically. A value of 0 turns the callback off.

If the value has to change-parameter is set to true, the callback is only triggered after the value has changed. If the value didn't change within the period, the callback is triggered immediately on change.

If it is set to false, the callback is continuously triggered with the period, independent of the value.

It is furthermore possible to constrain the callback with thresholds.

The option-parameter together with min/max sets a threshold for the CO2_V2_CALLBACK_HUMIDITY callback.

The following options are possible:

Option Description
'x' Threshold is turned off
'o' Threshold is triggered when the value is outside the min and max values
'i' Threshold is triggered when the value is inside or equal to the min and max values
'<' Threshold is triggered when the value is smaller than the min value (max is ignored)
'>' Threshold is triggered when the value is greater than the min value (max is ignored)

If the option is set to 'x' (threshold turned off) the callback is triggered with the fixed period.

The default value is (0, false, 'x', 0, 0).

The following defines are available for this function:

  • CO2_V2_THRESHOLD_OPTION_OFF = 'x'
  • CO2_V2_THRESHOLD_OPTION_OUTSIDE = 'o'
  • CO2_V2_THRESHOLD_OPTION_INSIDE = 'i'
  • CO2_V2_THRESHOLD_OPTION_SMALLER = '<'
  • CO2_V2_THRESHOLD_OPTION_GREATER = '>'
int co2_v2_get_humidity_callback_configuration(CO2V2 *co2_v2, uint32_t *ret_period, bool *ret_value_has_to_change, char *ret_option, uint16_t *ret_min, uint16_t *ret_max)

Returns the callback configuration as set by co2_v2_set_humidity_callback_configuration().

The following defines are available for this function:

  • CO2_V2_THRESHOLD_OPTION_OFF = 'x'
  • CO2_V2_THRESHOLD_OPTION_OUTSIDE = 'o'
  • CO2_V2_THRESHOLD_OPTION_INSIDE = 'i'
  • CO2_V2_THRESHOLD_OPTION_SMALLER = '<'
  • CO2_V2_THRESHOLD_OPTION_GREATER = '>'

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the co2_v2_register_callback() function. The parameters consist of the device object, the callback ID, the callback function and optional user data:

void my_callback(int p, void *user_data) {
    printf("parameter: %d\n", p);
}

co2_v2_register_callback(&co2_v2, CO2_V2_CALLBACK_EXAMPLE, (void *)my_callback, NULL);

The available constants with corresponding callback function signatures are described below.

Note

Using callbacks for recurring events is always preferred compared to using getters. It will use less USB bandwidth and the latency will be a lot better, since there is no round trip time.

CO2_V2_CALLBACK_ALL_VALUES
void callback(uint16_t co2_concentration, int16_t temperature, uint16_t humidity, void *user_data)

This callback is triggered periodically according to the configuration set by co2_v2_set_all_values_callback_configuration().

The parameters are the same as co2_v2_get_all_values().

CO2_V2_CALLBACK_CO2_CONCENTRATION
void callback(uint16_t co2_concentration, void *user_data)

This callback is triggered periodically according to the configuration set by co2_v2_set_co2_concentration_callback_configuration().

The parameter is the same as co2_v2_get_co2_concentration().

CO2_V2_CALLBACK_TEMPERATURE
void callback(int16_t temperature, void *user_data)

This callback is triggered periodically according to the configuration set by co2_v2_set_temperature_callback_configuration().

The parameter is the same as co2_v2_get_temperature().

CO2_V2_CALLBACK_HUMIDITY
void callback(uint16_t humidity, void *user_data)

This callback is triggered periodically according to the configuration set by co2_v2_set_humidity_callback_configuration().

The parameter is the same as co2_v2_get_humidity().

Constants

CO2_V2_DEVICE_IDENTIFIER

This constant is used to identify a CO2 Bricklet 2.0.

The co2_v2_get_identity() function and the IPCON_CALLBACK_ENUMERATE callback of the IP Connection have a device_identifier parameter to specify the Brick's or Bricklet's type.

CO2_V2_DEVICE_DISPLAY_NAME

This constant represents the human readable name of a CO2 Bricklet 2.0.