Rust - Dual Button Bricklet

This is the description of the Rust API bindings for the Dual Button Bricklet. General information and technical specifications for the Dual Button Bricklet are summarized in its hardware description.

An installation guide for the Rust API bindings is part of their general description. Additional documentation can be found on docs.rs.

Examples

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

Callback

Download (example_callback.rs)

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use std::{error::Error, io, thread};
use tinkerforge::{dual_button_bricklet::*, ip_connection::IpConnection};

const HOST: &str = "localhost";
const PORT: u16 = 4223;
const UID: &str = "XYZ"; // Change XYZ to the UID of your Dual Button Bricklet.

fn main() -> Result<(), Box<dyn Error>> {
    let ipcon = IpConnection::new(); // Create IP connection.
    let db = DualButtonBricklet::new(UID, &ipcon); // Create device object.

    ipcon.connect((HOST, PORT)).recv()??; // Connect to brickd.
                                          // Don't use device before ipcon is connected.

    let state_changed_receiver = db.get_state_changed_callback_receiver();

    // Spawn thread to handle received callback messages.
    // This thread ends when the `db` object
    // is dropped, so there is no need for manual cleanup.
    thread::spawn(move || {
        for state_changed in state_changed_receiver {
            if state_changed.button_l == DUAL_BUTTON_BRICKLET_BUTTON_STATE_PRESSED {
                println!("Left Button: Pressed");
            } else if state_changed.button_l == DUAL_BUTTON_BRICKLET_BUTTON_STATE_RELEASED {
                println!("Left Button: Released");
            }

            if state_changed.button_r == DUAL_BUTTON_BRICKLET_BUTTON_STATE_PRESSED {
                println!("Right Button: Pressed");
            } else if state_changed.button_r == DUAL_BUTTON_BRICKLET_BUTTON_STATE_RELEASED {
                println!("Right Button: Released");
            }

            println!();
        }
    });

    println!("Press enter to exit.");
    let mut _input = String::new();
    io::stdin().read_line(&mut _input)?;
    ipcon.disconnect();
    Ok(())
}

API

To allow non-blocking usage, nearly every function of the Rust bindings returns a wrapper around a mpsc::Receiver. To block until the function has finished and get your result, call one of the receiver's recv variants. Those return either the result sent by the device, or any error occured.

Functions returning a result directly will block until the device has finished processing the request.

All functions listed below are thread-safe, those which return a receiver are lock-free.

Basic Functions

pub fn DualButtonBricklet::new(uid: &str, ip_connection: &IpConnection) → DualButtonBricklet

Creates a new DualButtonBricklet object with the unique device ID uid and adds it to the IPConnection ipcon:

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

pub fn DualButtonBricklet::set_led_state(&self, led_l: u8, led_r: u8) → ConvertingReceiver<()>

Sets the state of the LEDs. Possible states are:

  • 0 = AutoToggleOn: Enables auto toggle with initially enabled LED.
  • 1 = AutoToggleOff: Activates auto toggle with initially disabled LED.
  • 2 = On: Enables LED (auto toggle is disabled).
  • 3 = Off: Disables LED (auto toggle is disabled).

In auto toggle mode the LED is toggled automatically at each press of a button.

If you just want to set one of the LEDs and don't know the current state of the other LED, you can get the state with DualButtonBricklet::get_led_state or you can use DualButtonBricklet::set_selected_led_state.

The default value is (1, 1).

The following constants are available for this function:

  • DUAL_BUTTON_BRICKLET_LED_STATE_AUTO_TOGGLE_ON = 0
  • DUAL_BUTTON_BRICKLET_LED_STATE_AUTO_TOGGLE_OFF = 1
  • DUAL_BUTTON_BRICKLET_LED_STATE_ON = 2
  • DUAL_BUTTON_BRICKLET_LED_STATE_OFF = 3
pub fn DualButtonBricklet::get_led_state(&self) → ConvertingReceiver<LedState>

Returns the current state of the LEDs, as set by DualButtonBricklet::set_led_state.

The following constants are available for this function:

  • DUAL_BUTTON_BRICKLET_LED_STATE_AUTO_TOGGLE_ON = 0
  • DUAL_BUTTON_BRICKLET_LED_STATE_AUTO_TOGGLE_OFF = 1
  • DUAL_BUTTON_BRICKLET_LED_STATE_ON = 2
  • DUAL_BUTTON_BRICKLET_LED_STATE_OFF = 3
pub fn DualButtonBricklet::get_button_state(&self) → ConvertingReceiver<ButtonState>

Returns the current state for both buttons. Possible states are:

  • 0 = pressed
  • 1 = released

The following constants are available for this function:

  • DUAL_BUTTON_BRICKLET_BUTTON_STATE_PRESSED = 0
  • DUAL_BUTTON_BRICKLET_BUTTON_STATE_RELEASED = 1

Advanced Functions

pub fn DualButtonBricklet::set_selected_led_state(&self, led: u8, state: u8) → ConvertingReceiver<()>

Sets the state of the selected LED (0 or 1).

The other LED remains untouched.

The following constants are available for this function:

  • DUAL_BUTTON_BRICKLET_LED_LEFT = 0
  • DUAL_BUTTON_BRICKLET_LED_RIGHT = 1
  • DUAL_BUTTON_BRICKLET_LED_STATE_AUTO_TOGGLE_ON = 0
  • DUAL_BUTTON_BRICKLET_LED_STATE_AUTO_TOGGLE_OFF = 1
  • DUAL_BUTTON_BRICKLET_LED_STATE_ON = 2
  • DUAL_BUTTON_BRICKLET_LED_STATE_OFF = 3
pub fn DualButtonBricklet::get_api_version(&self) → [u8; 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.

pub fn DualButtonBricklet::get_response_expected(&mut self, function_id: u8) → bool

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 DualButtonBricklet::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 DualButtonBricklet::set_response_expected for the list of function ID constants available for this function.

pub fn DualButtonBricklet::set_response_expected(&mut self, function_id: u8, response_expected: bool) → ()

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 constants are available for this function:

  • DUAL_BUTTON_BRICKLET_FUNCTION_SET_LED_STATE = 1
  • DUAL_BUTTON_BRICKLET_FUNCTION_SET_SELECTED_LED_STATE = 5
pub fn DualButtonBricklet::set_response_expected_all(&mut self, response_expected: bool) → ()

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

pub fn DualButtonBricklet::get_identity(&self) → ConvertingReceiver<Identity>

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.

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the corresponding get_*_callback_receiver function, which returns a receiver for callback events.

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.

pub fn DualButtonBricklet::get_state_changed_callback_receiver(&self) → ConvertingCallbackReceiver<StateChangedEvent>

Receivers created with this function receive State Changed events.

This callback is called whenever a button is pressed.

Possible states for buttons are:

  • 0 = pressed
  • 1 = released

Possible states for LEDs are:

  • 0 = AutoToggleOn: Auto toggle enabled and LED on.
  • 1 = AutoToggleOff: Auto toggle enabled and LED off.
  • 2 = On: LED on (auto toggle is disabled).
  • 3 = Off: LED off (auto toggle is disabled).

The following constants are available for this function:

  • DUAL_BUTTON_BRICKLET_BUTTON_STATE_PRESSED = 0
  • DUAL_BUTTON_BRICKLET_BUTTON_STATE_RELEASED = 1
  • DUAL_BUTTON_BRICKLET_LED_STATE_AUTO_TOGGLE_ON = 0
  • DUAL_BUTTON_BRICKLET_LED_STATE_AUTO_TOGGLE_OFF = 1
  • DUAL_BUTTON_BRICKLET_LED_STATE_ON = 2
  • DUAL_BUTTON_BRICKLET_LED_STATE_OFF = 3

Constants

DualButtonBricklet::DEVICE_IDENTIFIER

This constant is used to identify a Dual Button Bricklet.

The DualButtonBricklet::get_identity function and the IpConnection::get_enumerate_callback_receiver callback of the IP Connection have a device_identifier parameter to specify the Brick's or Bricklet's type.

DualButtonBricklet::DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Dual Button Bricklet.