C/C++ - PTC Bricklet

This is the description of the C/C++ API bindings for the PTC Bricklet. General information and technical specifications for the PTC Bricklet 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_ptc.h"

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

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

    // Create device object
    PTC ptc;
    ptc_create(&ptc, 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 temperature
    int32_t temperature;
    if(ptc_get_temperature(&ptc, &temperature) < 0) {
        fprintf(stderr, "Could not get temperature, probably timeout\n");
        return 1;
    }

    printf("Temperature: %f °C\n", temperature/100.0);

    printf("Press key to exit\n");
    getchar();
    ptc_destroy(&ptc);
    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_ptc.h"

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

// Callback function for temperature callback
void cb_temperature(int32_t temperature, void *user_data) {
    (void)user_data; // avoid unused parameter warning

    printf("Temperature: %f °C\n", temperature/100.0);
}

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

    // Create device object
    PTC ptc;
    ptc_create(&ptc, 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 temperature callback to function cb_temperature
    ptc_register_callback(&ptc,
                          PTC_CALLBACK_TEMPERATURE,
                          (void (*)(void))cb_temperature,
                          NULL);

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

    printf("Press key to exit\n");
    getchar();
    ptc_destroy(&ptc);
    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_ptc.h"

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

// Callback function for temperature reached callback
void cb_temperature_reached(int32_t temperature, void *user_data) {
    (void)user_data; // avoid unused parameter warning

    printf("Temperature: %f °C\n", temperature/100.0);
}

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

    // Create device object
    PTC ptc;
    ptc_create(&ptc, 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)
    ptc_set_debounce_period(&ptc, 10000);

    // Register temperature reached callback to function cb_temperature_reached
    ptc_register_callback(&ptc,
                          PTC_CALLBACK_TEMPERATURE_REACHED,
                          (void (*)(void))cb_temperature_reached,
                          NULL);

    // Configure threshold for temperature "greater than 30 °C"
    ptc_set_temperature_callback_threshold(&ptc, '>', 30*100, 0);

    printf("Press key to exit\n");
    getchar();
    ptc_destroy(&ptc);
    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 ptc_create(PTC *ptc, const char *uid, IPConnection *ipcon)

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

PTC ptc;
ptc_create(&ptc, "YOUR_DEVICE_UID", &ipcon);

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

void ptc_destroy(PTC *ptc)

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

int ptc_get_temperature(PTC *ptc, int32_t *ret_temperature)

Returns the temperature of connected sensor. The value has a range of -246 to 849 °C and is given in °C/100, e.g. a value of 4223 means that a temperature of 42.23 °C is measured.

If you want to get the temperature periodically, it is recommended to use the PTC_CALLBACK_TEMPERATURE callback and set the period with ptc_set_temperature_callback_period().

int ptc_is_sensor_connected(PTC *ptc, bool *ret_connected)

Returns true if the sensor is connected correctly.

If this function returns false, there is either no Pt100 or Pt1000 sensor connected, the sensor is connected incorrectly or the sensor itself is faulty.

int ptc_set_wire_mode(PTC *ptc, uint8_t mode)

Sets the wire mode of the sensor. Possible values are 2, 3 and 4 which correspond to 2-, 3- and 4-wire sensors. The value has to match the jumper configuration on the Bricklet.

The default value is 2 = 2-wire.

The following defines are available for this function:

  • PTC_WIRE_MODE_2 = 2
  • PTC_WIRE_MODE_3 = 3
  • PTC_WIRE_MODE_4 = 4
int ptc_get_wire_mode(PTC *ptc, uint8_t *ret_mode)

Returns the wire mode as set by ptc_set_wire_mode()

The following defines are available for this function:

  • PTC_WIRE_MODE_2 = 2
  • PTC_WIRE_MODE_3 = 3
  • PTC_WIRE_MODE_4 = 4

Advanced Functions

int ptc_get_resistance(PTC *ptc, int32_t *ret_resistance)

Returns the value as measured by the MAX31865 precision delta-sigma ADC.

The value can be converted with the following formulas:

  • Pt100: resistance = (value * 390) / 32768
  • Pt1000: resistance = (value * 3900) / 32768

If you want to get the resistance periodically, it is recommended to use the PTC_CALLBACK_RESISTANCE callback and set the period with ptc_set_resistance_callback_period().

int ptc_set_noise_rejection_filter(PTC *ptc, uint8_t filter)

Sets the noise rejection filter to either 50Hz (0) or 60Hz (1). Noise from 50Hz or 60Hz power sources (including harmonics of the AC power's fundamental frequency) is attenuated by 82dB.

Default value is 0 = 50Hz.

The following defines are available for this function:

  • PTC_FILTER_OPTION_50HZ = 0
  • PTC_FILTER_OPTION_60HZ = 1
int ptc_get_noise_rejection_filter(PTC *ptc, uint8_t *ret_filter)

Returns the noise rejection filter option as set by ptc_set_noise_rejection_filter()

The following defines are available for this function:

  • PTC_FILTER_OPTION_50HZ = 0
  • PTC_FILTER_OPTION_60HZ = 1
int ptc_get_api_version(PTC *ptc, 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 ptc_get_response_expected(PTC *ptc, 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 ptc_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 ptc_set_response_expected() for the list of function ID defines available for this function.

int ptc_set_response_expected(PTC *ptc, 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:

  • PTC_FUNCTION_SET_TEMPERATURE_CALLBACK_PERIOD = 3
  • PTC_FUNCTION_SET_RESISTANCE_CALLBACK_PERIOD = 5
  • PTC_FUNCTION_SET_TEMPERATURE_CALLBACK_THRESHOLD = 7
  • PTC_FUNCTION_SET_RESISTANCE_CALLBACK_THRESHOLD = 9
  • PTC_FUNCTION_SET_DEBOUNCE_PERIOD = 11
  • PTC_FUNCTION_SET_NOISE_REJECTION_FILTER = 17
  • PTC_FUNCTION_SET_WIRE_MODE = 20
  • PTC_FUNCTION_SET_SENSOR_CONNECTED_CALLBACK_CONFIGURATION = 22
int ptc_set_response_expected_all(PTC *ptc, bool response_expected)

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

int ptc_get_identity(PTC *ptc, 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 ptc_register_callback(PTC *ptc, int16_t callback_id, void (*function)(void), 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 ptc_set_temperature_callback_period(PTC *ptc, uint32_t period)

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

The PTC_CALLBACK_TEMPERATURE callback is only triggered if the temperature has changed since the last triggering.

The default value is 0.

int ptc_get_temperature_callback_period(PTC *ptc, uint32_t *ret_period)

Returns the period as set by ptc_set_temperature_callback_period().

int ptc_set_resistance_callback_period(PTC *ptc, uint32_t period)

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

The PTC_CALLBACK_RESISTANCE callback is only triggered if the resistance has changed since the last triggering.

The default value is 0.

int ptc_get_resistance_callback_period(PTC *ptc, uint32_t *ret_period)

Returns the period as set by ptc_set_resistance_callback_period().

int ptc_set_temperature_callback_threshold(PTC *ptc, char option, int32_t min, int32_t max)

Sets the thresholds for the PTC_CALLBACK_TEMPERATURE_REACHED callback.

The following options are possible:

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

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

The following defines are available for this function:

  • PTC_THRESHOLD_OPTION_OFF = 'x'
  • PTC_THRESHOLD_OPTION_OUTSIDE = 'o'
  • PTC_THRESHOLD_OPTION_INSIDE = 'i'
  • PTC_THRESHOLD_OPTION_SMALLER = '<'
  • PTC_THRESHOLD_OPTION_GREATER = '>'
int ptc_get_temperature_callback_threshold(PTC *ptc, char *ret_option, int32_t *ret_min, int32_t *ret_max)

Returns the threshold as set by ptc_set_temperature_callback_threshold().

The following defines are available for this function:

  • PTC_THRESHOLD_OPTION_OFF = 'x'
  • PTC_THRESHOLD_OPTION_OUTSIDE = 'o'
  • PTC_THRESHOLD_OPTION_INSIDE = 'i'
  • PTC_THRESHOLD_OPTION_SMALLER = '<'
  • PTC_THRESHOLD_OPTION_GREATER = '>'
int ptc_set_resistance_callback_threshold(PTC *ptc, char option, int32_t min, int32_t max)

Sets the thresholds for the PTC_CALLBACK_RESISTANCE_REACHED callback.

The following options are possible:

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

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

The following defines are available for this function:

  • PTC_THRESHOLD_OPTION_OFF = 'x'
  • PTC_THRESHOLD_OPTION_OUTSIDE = 'o'
  • PTC_THRESHOLD_OPTION_INSIDE = 'i'
  • PTC_THRESHOLD_OPTION_SMALLER = '<'
  • PTC_THRESHOLD_OPTION_GREATER = '>'
int ptc_get_resistance_callback_threshold(PTC *ptc, char *ret_option, int32_t *ret_min, int32_t *ret_max)

Returns the threshold as set by ptc_set_resistance_callback_threshold().

The following defines are available for this function:

  • PTC_THRESHOLD_OPTION_OFF = 'x'
  • PTC_THRESHOLD_OPTION_OUTSIDE = 'o'
  • PTC_THRESHOLD_OPTION_INSIDE = 'i'
  • PTC_THRESHOLD_OPTION_SMALLER = '<'
  • PTC_THRESHOLD_OPTION_GREATER = '>'
int ptc_set_debounce_period(PTC *ptc, uint32_t debounce)

Sets the period in ms with which the threshold callback

is triggered, if the threshold

keeps being reached.

The default value is 100.

int ptc_get_debounce_period(PTC *ptc, uint32_t *ret_debounce)

Returns the debounce period as set by ptc_set_debounce_period().

int ptc_set_sensor_connected_callback_configuration(PTC *ptc, bool enabled)

If you enable this callback, the PTC_CALLBACK_SENSOR_CONNECTED callback is triggered every time a Pt sensor is connected/disconnected.

By default this callback is disabled.

New in version 2.0.2 (Plugin).

int ptc_get_sensor_connected_callback_configuration(PTC *ptc, bool *ret_enabled)

Returns the configuration as set by ptc_set_sensor_connected_callback_configuration().

New in version 2.0.2 (Plugin).

Callbacks

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

ptc_register_callback(&ptc, PTC_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.

PTC_CALLBACK_TEMPERATURE
void callback(int32_t temperature, void *user_data)

This callback is triggered periodically with the period that is set by ptc_set_temperature_callback_period(). The parameter is the temperature of the connected sensor.

The PTC_CALLBACK_TEMPERATURE callback is only triggered if the temperature has changed since the last triggering.

PTC_CALLBACK_TEMPERATURE_REACHED
void callback(int32_t temperature, void *user_data)

This callback is triggered when the threshold as set by ptc_set_temperature_callback_threshold() is reached. The parameter is the temperature of the connected sensor.

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

PTC_CALLBACK_RESISTANCE
void callback(int32_t resistance, void *user_data)

This callback is triggered periodically with the period that is set by ptc_set_resistance_callback_period(). The parameter is the resistance of the connected sensor.

The PTC_CALLBACK_RESISTANCE callback is only triggered if the resistance has changed since the last triggering.

PTC_CALLBACK_RESISTANCE_REACHED
void callback(int32_t resistance, void *user_data)

This callback is triggered when the threshold as set by ptc_set_resistance_callback_threshold() is reached. The parameter is the resistance of the connected sensor.

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

PTC_CALLBACK_SENSOR_CONNECTED
void callback(bool connected, void *user_data)

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

The parameter is the same as ptc_is_sensor_connected().

New in version 2.0.2 (Plugin).

Constants

PTC_DEVICE_IDENTIFIER

This constant is used to identify a PTC Bricklet.

The ptc_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.

PTC_DEVICE_DISPLAY_NAME

This constant represents the human readable name of a PTC Bricklet.