Rust - Rotary Encoder Bricklet

This is the description of the Rust API bindings for the Rotary Encoder Bricklet. General information and technical specifications for the Rotary Encoder 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).

Simple

Download (example_simple.rs)

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use std::{error::Error, io};

use tinkerforge::{ip_connection::IpConnection, rotary_encoder_bricklet::*};

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

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

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

    // Get current count without reset.
    let count = re.get_count(false).recv()?;
    println!("Count: {}", count);

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

Callback

Download (example_callback.rs)

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

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

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

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

    let count_receiver = re.get_count_callback_receiver();

    // Spawn thread to handle received callback messages.
    // This thread ends when the `re` object
    // is dropped, so there is no need for manual cleanup.
    thread::spawn(move || {
        for count in count_receiver {
            println!("Count: {}", count);
        }
    });

    // Set period for count receiver to 0.05s (50ms).
    // Note: The count callback is only called every 0.05 seconds
    //       if the count has changed since the last call!
    re.set_count_callback_period(50);

    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 occurred.

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 RotaryEncoderBricklet::new(uid: &str, ip_connection: &IpConnection) → RotaryEncoderBricklet
Parameters:
  • uid – Type: &str
  • ip_connection – Type: &IPConnection
Returns:
  • rotary_encoder – Type: RotaryEncoderBricklet

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

let rotary_encoder = RotaryEncoderBricklet::new("YOUR_DEVICE_UID", &ip_connection);

This device object can be used after the IP connection has been connected.

pub fn RotaryEncoderBricklet::get_count(&self, reset: bool) → ConvertingReceiver<i32>
Parameters:
  • reset – Type: bool
Returns:
  • count – Type: i32, Range: [-231 to 231 - 1]

Returns the current count of the encoder. If you set reset to true, the count is set back to 0 directly after the current count is read.

The encoder has 24 steps per rotation

Turning the encoder to the left decrements the counter, so a negative count is possible.

pub fn RotaryEncoderBricklet::is_pressed(&self) → ConvertingReceiver<bool>
Returns:
  • pressed – Type: bool

Returns true if the button is pressed and false otherwise.

It is recommended to use the RotaryEncoderBricklet::get_pressed_callback_receiver and RotaryEncoderBricklet::get_released_callback_receiver callbacks to handle the button.

Advanced Functions

pub fn RotaryEncoderBricklet::get_identity(&self) → ConvertingReceiver<Identity>
Return Object:
  • uid – Type: String, Length: up to 8
  • connected_uid – Type: String, Length: up to 8
  • position – Type: char, Range: ['a' to 'h', 'i', 'z']
  • hardware_version – Type: [u8; 3]
    • 0: major – Type: u8, Range: [0 to 255]
    • 1: minor – Type: u8, Range: [0 to 255]
    • 2: revision – Type: u8, Range: [0 to 255]
  • firmware_version – Type: [u8; 3]
    • 0: major – Type: u8, Range: [0 to 255]
    • 1: minor – Type: u8, Range: [0 to 255]
    • 2: revision – Type: u8, Range: [0 to 255]
  • device_identifier – Type: u16, Range: [0 to 216 - 1]

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', 'd', 'e', 'f', 'g' or 'h' (Bricklet Port). The Raspberry Pi HAT (Zero) Brick is always at position 'i' and the Bricklet connected to an Isolator Bricklet is always as position 'z'.

The device identifier numbers can be found here. There is also a constant for the device identifier of this Bricklet.

Callback Configuration Functions

pub fn RotaryEncoderBricklet::set_count_callback_period(&self, period: u32) → ConvertingReceiver<()>
Parameters:
  • period – Type: u32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Sets the period with which the RotaryEncoderBricklet::get_count_callback_receiver callback is triggered periodically. A value of 0 turns the callback off.

The RotaryEncoderBricklet::get_count_callback_receiver callback is only triggered if the count has changed since the last triggering.

pub fn RotaryEncoderBricklet::get_count_callback_period(&self) → ConvertingReceiver<u32>
Returns:
  • period – Type: u32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by RotaryEncoderBricklet::set_count_callback_period.

pub fn RotaryEncoderBricklet::set_count_callback_threshold(&self, option: char, min: i32, max: i32) → ConvertingReceiver<()>
Parameters:
  • option – Type: char, Range: See constants, Default: 'x'
  • min – Type: i32, Range: [-231 to 231 - 1], Default: 0
  • max – Type: i32, Range: [-231 to 231 - 1], Default: 0

Sets the thresholds for the RotaryEncoderBricklet::get_count_reached_callback_receiver callback.

The following options are possible:

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

The following constants are available for this function:

For option:

  • ROTARY_ENCODER_BRICKLET_THRESHOLD_OPTION_OFF = 'x'
  • ROTARY_ENCODER_BRICKLET_THRESHOLD_OPTION_OUTSIDE = 'o'
  • ROTARY_ENCODER_BRICKLET_THRESHOLD_OPTION_INSIDE = 'i'
  • ROTARY_ENCODER_BRICKLET_THRESHOLD_OPTION_SMALLER = '<'
  • ROTARY_ENCODER_BRICKLET_THRESHOLD_OPTION_GREATER = '>'
pub fn RotaryEncoderBricklet::get_count_callback_threshold(&self) → ConvertingReceiver<CountCallbackThreshold>
Return Object:
  • option – Type: char, Range: See constants, Default: 'x'
  • min – Type: i32, Range: [-231 to 231 - 1], Default: 0
  • max – Type: i32, Range: [-231 to 231 - 1], Default: 0

Returns the threshold as set by RotaryEncoderBricklet::set_count_callback_threshold.

The following constants are available for this function:

For option:

  • ROTARY_ENCODER_BRICKLET_THRESHOLD_OPTION_OFF = 'x'
  • ROTARY_ENCODER_BRICKLET_THRESHOLD_OPTION_OUTSIDE = 'o'
  • ROTARY_ENCODER_BRICKLET_THRESHOLD_OPTION_INSIDE = 'i'
  • ROTARY_ENCODER_BRICKLET_THRESHOLD_OPTION_SMALLER = '<'
  • ROTARY_ENCODER_BRICKLET_THRESHOLD_OPTION_GREATER = '>'
pub fn RotaryEncoderBricklet::set_debounce_period(&self, debounce: u32) → ConvertingReceiver<()>
Parameters:
  • debounce – Type: u32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100

Sets the period with which the threshold callback

is triggered, if the thresholds

keeps being reached.

pub fn RotaryEncoderBricklet::get_debounce_period(&self) → ConvertingReceiver<u32>
Returns:
  • debounce – Type: u32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100

Returns the debounce period as set by RotaryEncoderBricklet::set_debounce_period.

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 RotaryEncoderBricklet::get_count_callback_receiver(&self) → ConvertingCallbackReceiver<i32>
Event:
  • count – Type: i32, Range: [-231 to 231 - 1]

Receivers created with this function receive Count events.

This callback is triggered periodically with the period that is set by RotaryEncoderBricklet::set_count_callback_period. The received variable is the count of the encoder.

The RotaryEncoderBricklet::get_count_callback_receiver callback is only triggered if the count has changed since the last triggering.

pub fn RotaryEncoderBricklet::get_count_reached_callback_receiver(&self) → ConvertingCallbackReceiver<i32>
Event:
  • count – Type: i32, Range: [-231 to 231 - 1]

Receivers created with this function receive Count Reached events.

This callback is triggered when the threshold as set by RotaryEncoderBricklet::set_count_callback_threshold is reached. The received variable is the count of the encoder.

If the threshold keeps being reached, the callback is triggered periodically with the period as set by RotaryEncoderBricklet::set_debounce_period.

pub fn RotaryEncoderBricklet::get_pressed_callback_receiver(&self) → ConvertingCallbackReceiver<()>

Receivers created with this function receive Pressed events.

This callback is triggered when the button is pressed.

pub fn RotaryEncoderBricklet::get_released_callback_receiver(&self) → ConvertingCallbackReceiver<()>

Receivers created with this function receive Released events.

This callback is triggered when the button is released.

Virtual Functions

Virtual functions don't communicate with the device itself, but operate only on the API bindings device object. They can be called without the corresponding IP Connection object being connected.

pub fn RotaryEncoderBricklet::get_api_version(&self) → [u8; 3]
Return Object:
  • api_version – Type: [u8; 3]
    • 0: major – Type: u8, Range: [0 to 255]
    • 1: minor – Type: u8, Range: [0 to 255]
    • 2: revision – Type: u8, Range: [0 to 255]

Returns the version of the API definition 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 RotaryEncoderBricklet::get_response_expected(&mut self, function_id: u8) → bool
Parameters:
  • function_id – Type: u8, Range: See constants
Returns:
  • response_expected – Type: 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 RotaryEncoderBricklet::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 sent and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For function_id:

  • ROTARY_ENCODER_BRICKLET_FUNCTION_SET_COUNT_CALLBACK_PERIOD = 2
  • ROTARY_ENCODER_BRICKLET_FUNCTION_SET_COUNT_CALLBACK_THRESHOLD = 4
  • ROTARY_ENCODER_BRICKLET_FUNCTION_SET_DEBOUNCE_PERIOD = 6
pub fn RotaryEncoderBricklet::set_response_expected(&mut self, function_id: u8, response_expected: bool) → ()
Parameters:
  • function_id – Type: u8, Range: See constants
  • response_expected – Type: 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 sent and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For function_id:

  • ROTARY_ENCODER_BRICKLET_FUNCTION_SET_COUNT_CALLBACK_PERIOD = 2
  • ROTARY_ENCODER_BRICKLET_FUNCTION_SET_COUNT_CALLBACK_THRESHOLD = 4
  • ROTARY_ENCODER_BRICKLET_FUNCTION_SET_DEBOUNCE_PERIOD = 6
pub fn RotaryEncoderBricklet::set_response_expected_all(&mut self, response_expected: bool) → ()
Parameters:
  • response_expected – Type: bool

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

Constants

pub const RotaryEncoderBricklet::DEVICE_IDENTIFIER

This constant is used to identify a Rotary Encoder Bricklet.

The RotaryEncoderBricklet::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.

pub const RotaryEncoderBricklet::DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Rotary Encoder Bricklet.