C/C++ - Analog In Bricklet 2.0

This is the description of the C/C++ API bindings for the Analog In Bricklet 2.0. General information and technical specifications for the Analog In 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_analog_in_v2.h"

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

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

    // Create device object
    AnalogInV2 ai;
    analog_in_v2_create(&ai, 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 voltage
    uint16_t voltage;
    if(analog_in_v2_get_voltage(&ai, &voltage) < 0) {
        fprintf(stderr, "Could not get voltage, probably timeout\n");
        return 1;
    }

    printf("Voltage: %f V\n", voltage/1000.0);

    printf("Press key to exit\n");
    getchar();
    analog_in_v2_destroy(&ai);
    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_analog_in_v2.h"

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

// Callback function for voltage callback
void cb_voltage(uint16_t voltage, void *user_data) {
    (void)user_data; // avoid unused parameter warning

    printf("Voltage: %f V\n", voltage/1000.0);
}

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

    // Create device object
    AnalogInV2 ai;
    analog_in_v2_create(&ai, 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 voltage callback to function cb_voltage
    analog_in_v2_register_callback(&ai,
                                   ANALOG_IN_V2_CALLBACK_VOLTAGE,
                                   (void *)cb_voltage,
                                   NULL);

    // Set period for voltage callback to 1s (1000ms)
    // Note: The voltage callback is only called every second
    //       if the voltage has changed since the last call!
    analog_in_v2_set_voltage_callback_period(&ai, 1000);

    printf("Press key to exit\n");
    getchar();
    analog_in_v2_destroy(&ai);
    ipcon_destroy(&ipcon); // Calls ipcon_disconnect internally
    return 0;
}

Threshold

Download (example_threshold.c)

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#include <stdio.h>

#include "ip_connection.h"
#include "bricklet_analog_in_v2.h"

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

// Callback function for voltage reached callback
void cb_voltage_reached(uint16_t voltage, void *user_data) {
    (void)user_data; // avoid unused parameter warning

    printf("Voltage: %f V\n", voltage/1000.0);
}

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

    // Create device object
    AnalogInV2 ai;
    analog_in_v2_create(&ai, 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 threshold callbacks with a debounce time of 10 seconds (10000ms)
    analog_in_v2_set_debounce_period(&ai, 10000);

    // Register voltage reached callback to function cb_voltage_reached
    analog_in_v2_register_callback(&ai,
                                   ANALOG_IN_V2_CALLBACK_VOLTAGE_REACHED,
                                   (void *)cb_voltage_reached,
                                   NULL);

    // Configure threshold for voltage "smaller than 5 V"
    analog_in_v2_set_voltage_callback_threshold(&ai, '<', 5*1000, 0);

    printf("Press key to exit\n");
    getchar();
    analog_in_v2_destroy(&ai);
    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 output parameters. 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 analog_in_v2_create(AnalogInV2 *analog_in_v2, const char *uid, IPConnection *ipcon)

Creates the device object analog_in_v2 with the unique device ID uid and adds it to the IPConnection ipcon:

AnalogInV2 analog_in_v2;
analog_in_v2_create(&analog_in_v2, "YOUR_DEVICE_UID", &ipcon);

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

void analog_in_v2_destroy(AnalogInV2 *analog_in_v2)

Removes the device object analog_in_v2 from its IPConnection and destroys it. The device object cannot be used anymore afterwards.

int analog_in_v2_get_voltage(AnalogInV2 *analog_in_v2, uint16_t *ret_voltage)

Returns the measured voltage. The value is in mV and between 0V and 42V. The resolution is approximately 10mV.

If you want to get the voltage periodically, it is recommended to use the ANALOG_IN_V2_CALLBACK_VOLTAGE callback and set the period with analog_in_v2_set_voltage_callback_period().

Advanced Functions

int analog_in_v2_get_analog_value(AnalogInV2 *analog_in_v2, uint16_t *ret_value)

Returns the value as read by a 12-bit analog-to-digital converter. The value is between 0 and 4095.

If you want the analog value periodically, it is recommended to use the ANALOG_IN_V2_CALLBACK_ANALOG_VALUE callback and set the period with analog_in_v2_set_analog_value_callback_period().

int analog_in_v2_set_moving_average(AnalogInV2 *analog_in_v2, uint8_t average)

Sets the length of a moving averaging for the voltage.

Setting the length to 1 will turn the averaging off. With less averaging, there is more noise on the data.

The range for the averaging is 1-50.

The default value is 50.

int analog_in_v2_get_moving_average(AnalogInV2 *analog_in_v2, uint8_t *ret_average)

Returns the length of the moving average as set by analog_in_v2_set_moving_average().

int analog_in_v2_get_api_version(AnalogInV2 *analog_in_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 analog_in_v2_get_response_expected(AnalogInV2 *analog_in_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 analog_in_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 analog_in_v2_set_response_expected() for the list of function ID defines available for this function.

int analog_in_v2_set_response_expected(AnalogInV2 *analog_in_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:

  • ANALOG_IN_V2_FUNCTION_SET_VOLTAGE_CALLBACK_PERIOD = 3
  • ANALOG_IN_V2_FUNCTION_SET_ANALOG_VALUE_CALLBACK_PERIOD = 5
  • ANALOG_IN_V2_FUNCTION_SET_VOLTAGE_CALLBACK_THRESHOLD = 7
  • ANALOG_IN_V2_FUNCTION_SET_ANALOG_VALUE_CALLBACK_THRESHOLD = 9
  • ANALOG_IN_V2_FUNCTION_SET_DEBOUNCE_PERIOD = 11
  • ANALOG_IN_V2_FUNCTION_SET_MOVING_AVERAGE = 13
int analog_in_v2_set_response_expected_all(AnalogInV2 *analog_in_v2, bool response_expected)

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

int analog_in_v2_get_identity(AnalogInV2 *analog_in_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 analog_in_v2_register_callback(AnalogInV2 *analog_in_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 analog_in_v2_set_voltage_callback_period(AnalogInV2 *analog_in_v2, uint32_t period)

Sets the period in ms with which the ANALOG_IN_V2_CALLBACK_VOLTAGE callback is triggered periodically. A value of 0 turns the callback off.

The ANALOG_IN_V2_CALLBACK_VOLTAGE callback is only triggered if the voltage has changed since the last triggering.

The default value is 0.

int analog_in_v2_get_voltage_callback_period(AnalogInV2 *analog_in_v2, uint32_t *ret_period)

Returns the period as set by analog_in_v2_set_voltage_callback_period().

int analog_in_v2_set_analog_value_callback_period(AnalogInV2 *analog_in_v2, uint32_t period)

Sets the period in ms with which the ANALOG_IN_V2_CALLBACK_ANALOG_VALUE callback is triggered periodically. A value of 0 turns the callback off.

The ANALOG_IN_V2_CALLBACK_ANALOG_VALUE callback is only triggered if the analog value has changed since the last triggering.

The default value is 0.

int analog_in_v2_get_analog_value_callback_period(AnalogInV2 *analog_in_v2, uint32_t *ret_period)

Returns the period as set by analog_in_v2_set_analog_value_callback_period().

int analog_in_v2_set_voltage_callback_threshold(AnalogInV2 *analog_in_v2, char option, uint16_t min, uint16_t max)

Sets the thresholds for the ANALOG_IN_V2_CALLBACK_VOLTAGE_REACHED callback.

The following options are possible:

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

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

The following defines are available for this function:

  • ANALOG_IN_V2_THRESHOLD_OPTION_OFF = 'x'
  • ANALOG_IN_V2_THRESHOLD_OPTION_OUTSIDE = 'o'
  • ANALOG_IN_V2_THRESHOLD_OPTION_INSIDE = 'i'
  • ANALOG_IN_V2_THRESHOLD_OPTION_SMALLER = '<'
  • ANALOG_IN_V2_THRESHOLD_OPTION_GREATER = '>'
int analog_in_v2_get_voltage_callback_threshold(AnalogInV2 *analog_in_v2, char *ret_option, uint16_t *ret_min, uint16_t *ret_max)

Returns the threshold as set by analog_in_v2_set_voltage_callback_threshold().

The following defines are available for this function:

  • ANALOG_IN_V2_THRESHOLD_OPTION_OFF = 'x'
  • ANALOG_IN_V2_THRESHOLD_OPTION_OUTSIDE = 'o'
  • ANALOG_IN_V2_THRESHOLD_OPTION_INSIDE = 'i'
  • ANALOG_IN_V2_THRESHOLD_OPTION_SMALLER = '<'
  • ANALOG_IN_V2_THRESHOLD_OPTION_GREATER = '>'
int analog_in_v2_set_analog_value_callback_threshold(AnalogInV2 *analog_in_v2, char option, uint16_t min, uint16_t max)

Sets the thresholds for the ANALOG_IN_V2_CALLBACK_ANALOG_VALUE_REACHED callback.

The following options are possible:

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

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

The following defines are available for this function:

  • ANALOG_IN_V2_THRESHOLD_OPTION_OFF = 'x'
  • ANALOG_IN_V2_THRESHOLD_OPTION_OUTSIDE = 'o'
  • ANALOG_IN_V2_THRESHOLD_OPTION_INSIDE = 'i'
  • ANALOG_IN_V2_THRESHOLD_OPTION_SMALLER = '<'
  • ANALOG_IN_V2_THRESHOLD_OPTION_GREATER = '>'
int analog_in_v2_get_analog_value_callback_threshold(AnalogInV2 *analog_in_v2, char *ret_option, uint16_t *ret_min, uint16_t *ret_max)

Returns the threshold as set by analog_in_v2_set_analog_value_callback_threshold().

The following defines are available for this function:

  • ANALOG_IN_V2_THRESHOLD_OPTION_OFF = 'x'
  • ANALOG_IN_V2_THRESHOLD_OPTION_OUTSIDE = 'o'
  • ANALOG_IN_V2_THRESHOLD_OPTION_INSIDE = 'i'
  • ANALOG_IN_V2_THRESHOLD_OPTION_SMALLER = '<'
  • ANALOG_IN_V2_THRESHOLD_OPTION_GREATER = '>'
int analog_in_v2_set_debounce_period(AnalogInV2 *analog_in_v2, uint32_t debounce)

Sets the period in ms with which the threshold callbacks

are triggered, if the thresholds

keep being reached.

The default value is 100.

int analog_in_v2_get_debounce_period(AnalogInV2 *analog_in_v2, uint32_t *ret_debounce)

Returns the debounce period as set by analog_in_v2_set_debounce_period().

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the analog_in_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);
}

analog_in_v2_register_callback(&analog_in_v2, ANALOG_IN_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.

ANALOG_IN_V2_CALLBACK_VOLTAGE
void callback(uint16_t voltage, void *user_data)

This callback is triggered periodically with the period that is set by analog_in_v2_set_voltage_callback_period(). The parameter is the voltage of the sensor.

Der ANALOG_IN_V2_CALLBACK_VOLTAGE callback is only triggered if the voltage has changed since the last triggering.

ANALOG_IN_V2_CALLBACK_ANALOG_VALUE
void callback(uint16_t value, void *user_data)

This callback is triggered periodically with the period that is set by analog_in_v2_set_analog_value_callback_period(). The parameter is the analog value of the sensor.

The ANALOG_IN_V2_CALLBACK_ANALOG_VALUE callback is only triggered if the voltage has changed since the last triggering.

ANALOG_IN_V2_CALLBACK_VOLTAGE_REACHED
void callback(uint16_t voltage, void *user_data)

This callback is triggered when the threshold as set by analog_in_v2_set_voltage_callback_threshold() is reached. The parameter is the voltage of the sensor.

If the threshold keeps being reached, the callback is triggered periodically with the period as set by analog_in_v2_set_debounce_period().

ANALOG_IN_V2_CALLBACK_ANALOG_VALUE_REACHED
void callback(uint16_t value, void *user_data)

This callback is triggered when the threshold as set by analog_in_v2_set_analog_value_callback_threshold() is reached. The parameter is the analog value of the sensor.

If the threshold keeps being reached, the callback is triggered periodically with the period as set by analog_in_v2_set_debounce_period().

Constants

ANALOG_IN_V2_DEVICE_IDENTIFIER

This constant is used to identify a Analog In Bricklet 2.0.

The analog_in_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.

ANALOG_IN_V2_DEVICE_DISPLAY_NAME

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