This is the description of the C/C++ API bindings for the Temperature Bricklet. General information and technical specifications for the Temperature Bricklet are summarized in its hardware description.
An installation guide for the C/C++ API bindings is part of their general description.
The example code below is Public Domain (CC0 1.0).
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 | #include <stdio.h>
#include "ip_connection.h"
#include "bricklet_temperature.h"
#define HOST "localhost"
#define PORT 4223
#define UID "XYZ" // Change to your UID
int main() {
// Create IP connection
IPConnection ipcon;
ipcon_create(&ipcon);
// Create device object
Temperature t;
temperature_create(&t, UID, &ipcon);
// Connect to brickd
if(ipcon_connect(&ipcon, HOST, PORT) < 0) {
fprintf(stderr, "Could not connect\n");
exit(1);
}
// Don't use device before ipcon is connected
// Get current temperature (unit is °C/100)
int16_t temperature;
if(temperature_get_temperature(&t, &temperature) < 0) {
fprintf(stderr, "Could not get value, probably timeout\n");
exit(1);
}
printf("Temperature: %f °C\n", temperature/100.0);
printf("Press key to exit\n");
getchar();
ipcon_destroy(&ipcon); // Calls ipcon_disconnect internally
}
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 | #include <stdio.h>
#include "ip_connection.h"
#include "bricklet_temperature.h"
#define HOST "localhost"
#define PORT 4223
#define UID "XYZ" // Change to your UID
// Callback function for temperature callback (parameter has unit °C/100)
void cb_temperature(int16_t temperature, void *user_data) {
(void)user_data; // avoid unused parameter warning
printf("Temperature: %f °C.\n", temperature/100.0);
}
int main() {
// Create IP connection
IPConnection ipcon;
ipcon_create(&ipcon);
// Create device object
Temperature t;
temperature_create(&t, UID, &ipcon);
// Connect to brickd
if(ipcon_connect(&ipcon, HOST, PORT) < 0) {
fprintf(stderr, "Could not connect\n");
exit(1);
}
// Don't use device before ipcon is connected
// Set Period for temperature callback to 1s (1000ms)
// Note: The callback is only called every second if the
// temperature has changed since the last call!
temperature_set_temperature_callback_period(&t, 1000);
// Register temperature callback to function cb_temperature
temperature_register_callback(&t,
TEMPERATURE_CALLBACK_TEMPERATURE,
(void *)cb_temperature,
NULL);
printf("Press key to exit\n");
getchar();
ipcon_destroy(&ipcon); // Calls ipcon_disconnect internally
}
|
Download (example_threshold.c)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 | #include <stdio.h>
#include "ip_connection.h"
#include "bricklet_temperature.h"
#define HOST "localhost"
#define PORT 4223
#define UID "XYZ" // Change to your UID
// Callback for temperature greater than 30 °C
void cb_reached(int16_t temperature, void *user_data) {
(void)user_data; // avoid unused parameter warning
printf("We have %f °C.\n", temperature/100.0);
printf("It is too hot, we need air conditioning!\n");
}
int main() {
// Create IP connection
IPConnection ipcon;
ipcon_create(&ipcon);
// Create device object
Temperature t;
temperature_create(&t, UID, &ipcon);
// Connect to brickd
if(ipcon_connect(&ipcon, HOST, PORT) < 0) {
fprintf(stderr, "Could not connect\n");
exit(1);
}
// Don't use device before ipcon is connected
//
// Get threshold callbacks with a debounce time of 10 seconds (10000ms)
temperature_set_debounce_period(&t, 10000);
// Register threshold reached callback to function cb_reached
temperature_register_callback(&t,
TEMPERATURE_CALLBACK_TEMPERATURE_REACHED,
(void *)cb_reached,
NULL);
// Configure threshold for "greater than 30 °C" (unit is °C/100)
temperature_set_temperature_callback_threshold(&t, '>', 30*100, 0);
printf("Press key to exit\n");
getchar();
ipcon_destroy(&ipcon); // Calls ipcon_disconnect internally
}
|
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:
as defined in ip_connection.h.
All functions listed below are thread-safe.
Creates the device object temperature with the unique device ID uid and adds it to the IPConnection ipcon:
Temperature temperature;
temperature_create(&temperature, "YOUR_DEVICE_UID", &ipcon);
This device object can be used after the IP connection has been connected (see examples above).
Removes the device object temperature from its IPConnection and destroys it. The device object cannot be used anymore afterwards.
Returns the temperature of the sensor. The value has a range of -2500 to 8500 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 callback TEMPERATURE_CALLBACK_TEMPERATURE and set the period with temperature_set_temperature_callback_period().
Sets the I2C mode. Possible modes are:
If you have problems with obvious outliers in the Temperature Bricklet measurements, they may be caused by EMI issues. In this case it may be helpful to lower the I2C speed.
It is however not recommended to lower the I2C speed in applications where a high throughput needs to be achieved.
The following defines are available for this function:
New in version 2.0.1 (Plugin).
Returns the I2C mode as set by temperature_set_i2c_mode().
The following defines are available for this function:
New in version 2.0.1 (Plugin).
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.
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 temperature_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 temperature_set_response_expected() for the list of function ID defines available for this function.
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 and callbacks it is always disabled.
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:
Changes the response expected flag for all setter and callback configuration functions of this device at once.
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.
Registers a callback with ID id to the function callback. The user_data will be given as a parameter of the callback.
The available IDs with corresponding function signatures are listed below.
Sets the period in ms with which the TEMPERATURE_CALLBACK_TEMPERATURE callback is triggered periodically. A value of 0 turns the callback off.
TEMPERATURE_CALLBACK_TEMPERATURE is only triggered if the temperature has changed since the last triggering.
The default value is 0.
Returns the period as set by temperature_set_temperature_callback_period().
Sets the thresholds for the TEMPERATURE_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:
Returns the threshold as set by temperature_set_temperature_callback_threshold().
The following defines are available for this function:
Sets the period in ms with which the threshold callback
is triggered, if the threshold
keeps being reached.
The default value is 100.
Returns the debounce period as set by temperature_set_debounce_period().
Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the temperature_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); } temperature_register_callback(&temperature, TEMPERATURE_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.
void callback(int16_t temperature, void *user_data)
This callback is triggered periodically with the period that is set by temperature_set_temperature_callback_period(). The parameter is the temperature of the sensor.
TEMPERATURE_CALLBACK_TEMPERATURE is only triggered if the temperature has changed since the last triggering.
void callback(int16_t temperature, void *user_data)
This callback is triggered when the threshold as set by temperature_set_temperature_callback_threshold() is reached. The parameter is the temperature of the sensor.
If the threshold keeps being reached, the callback is triggered periodically with the period as set by temperature_set_debounce_period().
This constant is used to identify a Temperature Bricklet.
The temperature_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.