Rust - Linear Poti Bricklet

This is the description of the Rust API bindings for the Linear Poti Bricklet. General information and technical specifications for the Linear Poti 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, linear_poti_bricklet::*};

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

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

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

    // Get current position.
    let position = lp.get_position().recv()?;
    println!("Position: {}", position); // Range: 0 to 100

    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, linear_poti_bricklet::*};

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

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

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

    let position_receiver = lp.get_position_callback_receiver();

    // Spawn thread to handle received callback messages.
    // This thread ends when the `lp` object
    // is dropped, so there is no need for manual cleanup.
    thread::spawn(move || {
        for position in position_receiver {
            println!("Position: {}", position); // Range: 0 to 100
        }
    });

    // Set period for position receiver to 0.05s (50ms).
    // Note: The position callback is only called every 0.05 seconds
    //       if the position has changed since the last call!
    lp.set_position_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 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 LinearPotiBricklet::new(uid: &str, ip_connection: &IpConnection) → LinearPotiBricklet

Creates a new LinearPotiBricklet 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 LinearPotiBricklet::get_position(&self) → ConvertingReceiver<u16>

Returns the position of the linear potentiometer. The value is between 0 (slider down) and 100 (slider up).

If you want to get the position periodically, it is recommended to use the LinearPotiBricklet::get_position_callback_receiver callback and set the period with LinearPotiBricklet::set_position_callback_period.

Advanced Functions

pub fn LinearPotiBricklet::get_analog_value(&self) → ConvertingReceiver<u16>

Returns the value as read by a 12-bit analog-to-digital converter. The value is between 0 and 4095.

Note

The value returned by LinearPotiBricklet::get_position is averaged over several samples to yield less noise, while LinearPotiBricklet::get_analog_value gives back raw unfiltered analog values. The only reason to use LinearPotiBricklet::get_analog_value is, if you need the full resolution of the analog-to-digital converter.

If you want the analog value periodically, it is recommended to use the LinearPotiBricklet::get_analog_value_callback_receiver callback and set the period with LinearPotiBricklet::set_analog_value_callback_period.

pub fn LinearPotiBricklet::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 LinearPotiBricklet::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 LinearPotiBricklet::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 LinearPotiBricklet::set_response_expected for the list of function ID constants available for this function.

pub fn LinearPotiBricklet::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:

  • LINEAR_POTI_BRICKLET_FUNCTION_SET_POSITION_CALLBACK_PERIOD = 3
  • LINEAR_POTI_BRICKLET_FUNCTION_SET_ANALOG_VALUE_CALLBACK_PERIOD = 5
  • LINEAR_POTI_BRICKLET_FUNCTION_SET_POSITION_CALLBACK_THRESHOLD = 7
  • LINEAR_POTI_BRICKLET_FUNCTION_SET_ANALOG_VALUE_CALLBACK_THRESHOLD = 9
  • LINEAR_POTI_BRICKLET_FUNCTION_SET_DEBOUNCE_PERIOD = 11
pub fn LinearPotiBricklet::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 LinearPotiBricklet::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.

Callback Configuration Functions

pub fn LinearPotiBricklet::set_position_callback_period(&self, period: u32) → ConvertingReceiver<()>

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

The LinearPotiBricklet::get_position_callback_receiver callback is only triggered if the position has changed since the last triggering.

The default value is 0.

pub fn LinearPotiBricklet::get_position_callback_period(&self) → ConvertingReceiver<u32>

Returns the period as set by LinearPotiBricklet::set_position_callback_period.

pub fn LinearPotiBricklet::set_analog_value_callback_period(&self, period: u32) → ConvertingReceiver<()>

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

The LinearPotiBricklet::get_analog_value_callback_receiver callback is only triggered if the analog value has changed since the last triggering.

The default value is 0.

pub fn LinearPotiBricklet::get_analog_value_callback_period(&self) → ConvertingReceiver<u32>

Returns the period as set by LinearPotiBricklet::set_analog_value_callback_period.

pub fn LinearPotiBricklet::set_position_callback_threshold(&self, option: char, min: u16, max: u16) → ConvertingReceiver<()>

Sets the thresholds for the LinearPotiBricklet::get_position_reached_callback_receiver callback.

The following options are possible:

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

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

The following constants are available for this function:

  • LINEAR_POTI_BRICKLET_THRESHOLD_OPTION_OFF = 'x'
  • LINEAR_POTI_BRICKLET_THRESHOLD_OPTION_OUTSIDE = 'o'
  • LINEAR_POTI_BRICKLET_THRESHOLD_OPTION_INSIDE = 'i'
  • LINEAR_POTI_BRICKLET_THRESHOLD_OPTION_SMALLER = '<'
  • LINEAR_POTI_BRICKLET_THRESHOLD_OPTION_GREATER = '>'
pub fn LinearPotiBricklet::get_position_callback_threshold(&self) → ConvertingReceiver<PositionCallbackThreshold>

Returns the threshold as set by LinearPotiBricklet::set_position_callback_threshold.

The following constants are available for this function:

  • LINEAR_POTI_BRICKLET_THRESHOLD_OPTION_OFF = 'x'
  • LINEAR_POTI_BRICKLET_THRESHOLD_OPTION_OUTSIDE = 'o'
  • LINEAR_POTI_BRICKLET_THRESHOLD_OPTION_INSIDE = 'i'
  • LINEAR_POTI_BRICKLET_THRESHOLD_OPTION_SMALLER = '<'
  • LINEAR_POTI_BRICKLET_THRESHOLD_OPTION_GREATER = '>'
pub fn LinearPotiBricklet::set_analog_value_callback_threshold(&self, option: char, min: u16, max: u16) → ConvertingReceiver<()>

Sets the thresholds for the LinearPotiBricklet::get_analog_value_reached_callback_receiver callback.

The following options are possible:

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

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

The following constants are available for this function:

  • LINEAR_POTI_BRICKLET_THRESHOLD_OPTION_OFF = 'x'
  • LINEAR_POTI_BRICKLET_THRESHOLD_OPTION_OUTSIDE = 'o'
  • LINEAR_POTI_BRICKLET_THRESHOLD_OPTION_INSIDE = 'i'
  • LINEAR_POTI_BRICKLET_THRESHOLD_OPTION_SMALLER = '<'
  • LINEAR_POTI_BRICKLET_THRESHOLD_OPTION_GREATER = '>'
pub fn LinearPotiBricklet::get_analog_value_callback_threshold(&self) → ConvertingReceiver<AnalogValueCallbackThreshold>

Returns the threshold as set by LinearPotiBricklet::set_analog_value_callback_threshold.

The following constants are available for this function:

  • LINEAR_POTI_BRICKLET_THRESHOLD_OPTION_OFF = 'x'
  • LINEAR_POTI_BRICKLET_THRESHOLD_OPTION_OUTSIDE = 'o'
  • LINEAR_POTI_BRICKLET_THRESHOLD_OPTION_INSIDE = 'i'
  • LINEAR_POTI_BRICKLET_THRESHOLD_OPTION_SMALLER = '<'
  • LINEAR_POTI_BRICKLET_THRESHOLD_OPTION_GREATER = '>'
pub fn LinearPotiBricklet::set_debounce_period(&self, debounce: u32) → ConvertingReceiver<()>

Sets the period in ms with which the threshold callbacks

are triggered, if the thresholds

keep being reached.

The default value is 100.

pub fn LinearPotiBricklet::get_debounce_period(&self) → ConvertingReceiver<u32>

Returns the debounce period as set by LinearPotiBricklet::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 LinearPotiBricklet::get_position_callback_receiver(&self) → ConvertingCallbackReceiver<u16>

Receivers created with this function receive Position events.

This callback is triggered periodically with the period that is set by LinearPotiBricklet::set_position_callback_period. The received variable is the position of the linear potentiometer.

The LinearPotiBricklet::get_position_callback_receiver callback is only triggered if the position has changed since the last triggering.

pub fn LinearPotiBricklet::get_analog_value_callback_receiver(&self) → ConvertingCallbackReceiver<u16>

Receivers created with this function receive Analog Value events.

This callback is triggered periodically with the period that is set by LinearPotiBricklet::set_analog_value_callback_period. The received variable is the analog value of the Linear Potentiometer.

The LinearPotiBricklet::get_analog_value_callback_receiver callback is only triggered if the position has changed since the last triggering.

pub fn LinearPotiBricklet::get_position_reached_callback_receiver(&self) → ConvertingCallbackReceiver<u16>

Receivers created with this function receive Position Reached events.

This callback is triggered when the threshold as set by LinearPotiBricklet::set_position_callback_threshold is reached. The received variable is the position of the linear potentiometer.

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

pub fn LinearPotiBricklet::get_analog_value_reached_callback_receiver(&self) → ConvertingCallbackReceiver<u16>

Receivers created with this function receive Analog Value Reached events.

This callback is triggered when the threshold as set by LinearPotiBricklet::set_analog_value_callback_threshold is reached. The received variable is the analog value of the linear potentiometer.

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

Constants

LinearPotiBricklet::DEVICE_IDENTIFIER

This constant is used to identify a Linear Poti Bricklet.

The LinearPotiBricklet::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.

LinearPotiBricklet::DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Linear Poti Bricklet.