C/C++ - RGB LED Bricklet

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

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

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

    // Create device object
    RGBLED rl;
    rgb_led_create(&rl, 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

    // Set light blue color
    rgb_led_set_rgb_value(&rl, 0, 170, 234);

    printf("Press key to exit\n");
    getchar();
    rgb_led_destroy(&rl);
    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

as defined in ip_connection.h.

All functions listed below are thread-safe.

Basic Functions

void rgb_led_create(RGBLED *rgb_led, const char *uid, IPConnection *ipcon)

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

RGBLED rgb_led;
rgb_led_create(&rgb_led, "YOUR_DEVICE_UID", &ipcon);

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

void rgb_led_destroy(RGBLED *rgb_led)

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

int rgb_led_set_rgb_value(RGBLED *rgb_led, uint8_t r, uint8_t g, uint8_t b)

Sets the rgb value for the LED. The value can be between 0 and 255.

int rgb_led_get_rgb_value(RGBLED *rgb_led, uint8_t *ret_r, uint8_t *ret_g, uint8_t *ret_b)

Returns the rgb value of the LED as set by rgb_led_set_rgb_value().

Advanced Functions

int rgb_led_get_api_version(RGBLED *rgb_led, 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 rgb_led_get_response_expected(RGBLED *rgb_led, 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 rgb_led_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 rgb_led_set_response_expected() for the list of function ID defines available for this function.

int rgb_led_set_response_expected(RGBLED *rgb_led, 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:

  • RGB_LED_FUNCTION_SET_RGB_VALUE = 1
int rgb_led_set_response_expected_all(RGBLED *rgb_led, bool response_expected)

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

int rgb_led_get_identity(RGBLED *rgb_led, 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.

Constants

RGB_LED_DEVICE_IDENTIFIER

This constant is used to identify a RGB LED Bricklet.

The rgb_led_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.

RGB_LED_DEVICE_DISPLAY_NAME

This constant represents the human readable name of a RGB LED Bricklet.