Rust - Multi Touch Bricklet 2.0

This is the description of the Rust API bindings for the Multi Touch Bricklet 2.0. General information and technical specifications for the Multi Touch Bricklet 2.0 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, multi_touch_v2_bricklet::*};

const HOST: &str = "localhost";
const PORT: u16 = 4223;
const UID: &str = "XYZ"; // Change XYZ to the UID of your Multi Touch Bricklet 2.0.

fn main() -> Result<(), Box<dyn Error>> {
    let ipcon = IpConnection::new(); // Create IP connection.
    let mt = MultiTouchV2Bricklet::new(UID, &ipcon); // Create device object.

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

    // Get current touch state.
    let state = mt.get_touch_state().recv()?;

    println!("Electrode 0: {}", state[0]);
    println!("Electrode 1: {}", state[1]);
    println!("Electrode 2: {}", state[2]);
    println!("Electrode 3: {}", state[3]);
    println!("Electrode 4: {}", state[4]);
    println!("Electrode 5: {}", state[5]);
    println!("Electrode 6: {}", state[6]);
    println!("Electrode 7: {}", state[7]);
    println!("Electrode 8: {}", state[8]);
    println!("Electrode 9: {}", state[9]);
    println!("Electrode 10: {}", state[10]);
    println!("Electrode 11: {}", state[11]);
    println!("Proximity: {}", state[12]);

    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, multi_touch_v2_bricklet::*};

const HOST: &str = "localhost";
const PORT: u16 = 4223;
const UID: &str = "XYZ"; // Change XYZ to the UID of your Multi Touch Bricklet 2.0.

fn main() -> Result<(), Box<dyn Error>> {
    let ipcon = IpConnection::new(); // Create IP connection.
    let mt = MultiTouchV2Bricklet::new(UID, &ipcon); // Create device object.

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

    let touch_state_receiver = mt.get_touch_state_callback_receiver();

    // Spawn thread to handle received callback messages.
    // This thread ends when the `mt` object
    // is dropped, so there is no need for manual cleanup.
    thread::spawn(move || {
        for touch_state in touch_state_receiver {
            println!("Electrode 0: {}", touch_state[0]);
            println!("Electrode 1: {}", touch_state[1]);
            println!("Electrode 2: {}", touch_state[2]);
            println!("Electrode 3: {}", touch_state[3]);
            println!("Electrode 4: {}", touch_state[4]);
            println!("Electrode 5: {}", touch_state[5]);
            println!("Electrode 6: {}", touch_state[6]);
            println!("Electrode 7: {}", touch_state[7]);
            println!("Electrode 8: {}", touch_state[8]);
            println!("Electrode 9: {}", touch_state[9]);
            println!("Electrode 10: {}", touch_state[10]);
            println!("Electrode 11: {}", touch_state[11]);
            println!("Proximity: {}", touch_state[12]);
            println!();
        }
    });

    // Set period for touch state callback to 0.01s (10ms).
    mt.set_touch_state_callback_configuration(10, true);

    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 MultiTouchV2Bricklet::new(uid: &str, ip_connection: &IpConnection) → MultiTouchV2Bricklet
Parameters:
  • uid – Type: &str
  • ip_connection – Type: &IPConnection
Returns:
  • multi_touch_v2 – Type: MultiTouchV2Bricklet

Creates a new MultiTouchV2Bricklet object with the unique device ID uid and adds it to the IPConnection ip_connection:

let multi_touch_v2 = MultiTouchV2Bricklet::new("YOUR_DEVICE_UID", &ip_connection);

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

pub fn MultiTouchV2Bricklet::get_touch_state(&self) → ConvertingReceiver<[bool; 13]>
Returns:
  • state – Type: [bool; 13]

Returns the current touch state. The state is given as a array of bools.

Element 0 to 11 represent the 12 electrodes and element 12 represents the proximity.

If an electrode is touched, the corresponding element is true. If a hand or similar is in proximity to the electrodes, element 12 is true.

The proximity is activated with a distance of 1-2cm. An electrode is already counted as touched if a finger is nearly touching the electrode. This means that you can put a piece of paper or foil or similar on top of a electrode to build a touch panel with a professional look.

If you want to get the value periodically, it is recommended to use the MultiTouchV2Bricklet::get_touch_state_callback_receiver callback. You can set the callback configuration with MultiTouchV2Bricklet::set_touch_state_callback_configuration.

pub fn MultiTouchV2Bricklet::recalibrate(&self) → ConvertingReceiver<()>

Recalibrates the electrodes. Call this function whenever you changed or moved you electrodes.

pub fn MultiTouchV2Bricklet::set_electrode_config(&self, enabled_electrodes: [bool; 13]) → ConvertingReceiver<()>
Parameters:
  • enabled_electrodes – Type: [bool; 13]

Enables/disables electrodes with a bool array (see MultiTouchV2Bricklet::get_touch_state).

True enables the electrode, false disables the electrode. A disabled electrode will always return false as its state. If you don't need all electrodes you can disable the electrodes that are not needed.

It is recommended that you disable the proximity electrode (element 12) if the proximity feature is not needed. This will reduce the amount of traffic that is produced by the MultiTouchV2Bricklet::get_touch_state_callback_receiver callback.

Disabling electrodes will also reduce power consumption.

Default: All electrodes enabled.

pub fn MultiTouchV2Bricklet::get_electrode_config(&self) → ConvertingReceiver<[bool; 13]>
Returns:
  • enabled_electrodes – Type: [bool; 13]

Returns the electrode configuration, as set by MultiTouchV2Bricklet::set_electrode_config.

pub fn MultiTouchV2Bricklet::set_electrode_sensitivity(&self, sensitivity: u8) → ConvertingReceiver<()>
Parameters:
  • sensitivity – Type: u8, Range: [0 to 255]

Sets the sensitivity of the electrodes. An electrode with a high sensitivity will register a touch earlier then an electrode with a low sensitivity.

If you build a big electrode you might need to decrease the sensitivity, since the area that can be charged will get bigger. If you want to be able to activate an electrode from further away you need to increase the sensitivity.

After a new sensitivity is set, you likely want to call MultiTouchV2Bricklet::recalibrate to calibrate the electrodes with the newly defined sensitivity.

The valid sensitivity value range is 5-201.

The default sensitivity value is 181.

pub fn MultiTouchV2Bricklet::get_electrode_sensitivity(&self) → ConvertingReceiver<u8>
Returns:
  • sensitivity – Type: u8, Range: [0 to 255]

Returns the current sensitivity, as set by MultiTouchV2Bricklet::set_electrode_sensitivity.

pub fn MultiTouchV2Bricklet::set_touch_led_config(&self, config: u8) → ConvertingReceiver<()>
Parameters:
  • config – Type: u8, Range: See constants

Configures the touch LED to be either turned off, turned on, blink in heartbeat mode or show the touch state (electrode touched = LED on).

The default value is 3 (show touch state).

The following constants are available for this function:

For config:

  • MULTI_TOUCH_V2_BRICKLET_TOUCH_LED_CONFIG_OFF = 0
  • MULTI_TOUCH_V2_BRICKLET_TOUCH_LED_CONFIG_ON = 1
  • MULTI_TOUCH_V2_BRICKLET_TOUCH_LED_CONFIG_SHOW_HEARTBEAT = 2
  • MULTI_TOUCH_V2_BRICKLET_TOUCH_LED_CONFIG_SHOW_TOUCH = 3
pub fn MultiTouchV2Bricklet::get_touch_led_config(&self) → ConvertingReceiver<u8>
Returns:
  • config – Type: u8, Range: See constants

Returns the LED configuration as set by MultiTouchV2Bricklet::set_touch_led_config

The following constants are available for this function:

For config:

  • MULTI_TOUCH_V2_BRICKLET_TOUCH_LED_CONFIG_OFF = 0
  • MULTI_TOUCH_V2_BRICKLET_TOUCH_LED_CONFIG_ON = 1
  • MULTI_TOUCH_V2_BRICKLET_TOUCH_LED_CONFIG_SHOW_HEARTBEAT = 2
  • MULTI_TOUCH_V2_BRICKLET_TOUCH_LED_CONFIG_SHOW_TOUCH = 3

Advanced Functions

pub fn MultiTouchV2Bricklet::get_api_version(&self) → [u8; 3]
Returns:
  • api_version – Type: [u8; 3], Range: [0 to 255]

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 MultiTouchV2Bricklet::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 MultiTouchV2Bricklet::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.

The following constants are available for this function:

For function_id:

  • MULTI_TOUCH_V2_BRICKLET_FUNCTION_SET_TOUCH_STATE_CALLBACK_CONFIGURATION = 2
  • MULTI_TOUCH_V2_BRICKLET_FUNCTION_RECALIBRATE = 5
  • MULTI_TOUCH_V2_BRICKLET_FUNCTION_SET_ELECTRODE_CONFIG = 6
  • MULTI_TOUCH_V2_BRICKLET_FUNCTION_SET_ELECTRODE_SENSITIVITY = 8
  • MULTI_TOUCH_V2_BRICKLET_FUNCTION_SET_TOUCH_LED_CONFIG = 10
  • MULTI_TOUCH_V2_BRICKLET_FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • MULTI_TOUCH_V2_BRICKLET_FUNCTION_SET_STATUS_LED_CONFIG = 239
  • MULTI_TOUCH_V2_BRICKLET_FUNCTION_RESET = 243
  • MULTI_TOUCH_V2_BRICKLET_FUNCTION_WRITE_UID = 248
pub fn MultiTouchV2Bricklet::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 send and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For function_id:

  • MULTI_TOUCH_V2_BRICKLET_FUNCTION_SET_TOUCH_STATE_CALLBACK_CONFIGURATION = 2
  • MULTI_TOUCH_V2_BRICKLET_FUNCTION_RECALIBRATE = 5
  • MULTI_TOUCH_V2_BRICKLET_FUNCTION_SET_ELECTRODE_CONFIG = 6
  • MULTI_TOUCH_V2_BRICKLET_FUNCTION_SET_ELECTRODE_SENSITIVITY = 8
  • MULTI_TOUCH_V2_BRICKLET_FUNCTION_SET_TOUCH_LED_CONFIG = 10
  • MULTI_TOUCH_V2_BRICKLET_FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • MULTI_TOUCH_V2_BRICKLET_FUNCTION_SET_STATUS_LED_CONFIG = 239
  • MULTI_TOUCH_V2_BRICKLET_FUNCTION_RESET = 243
  • MULTI_TOUCH_V2_BRICKLET_FUNCTION_WRITE_UID = 248
pub fn MultiTouchV2Bricklet::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.

pub fn MultiTouchV2Bricklet::get_spitfp_error_count(&self) → ConvertingReceiver<SpitfpErrorCount>
Return Object:
  • error_count_ack_checksum – Type: u32, Range: [0 to 232 - 1]
  • error_count_message_checksum – Type: u32, Range: [0 to 232 - 1]
  • error_count_frame – Type: u32, Range: [0 to 232 - 1]
  • error_count_overflow – Type: u32, Range: [0 to 232 - 1]

Returns the error count for the communication between Brick and Bricklet.

The errors are divided into

  • ACK checksum errors,
  • message checksum errors,
  • framing errors and
  • overflow errors.

The errors counts are for errors that occur on the Bricklet side. All Bricks have a similar function that returns the errors on the Brick side.

pub fn MultiTouchV2Bricklet::set_bootloader_mode(&self, mode: u8) → ConvertingReceiver<u8>
Parameters:
  • mode – Type: u8, Range: See constants
Returns:
  • status – Type: u8, Range: See constants

Sets the bootloader mode and returns the status after the requested mode change was instigated.

You can change from bootloader mode to firmware mode and vice versa. A change from bootloader mode to firmware mode will only take place if the entry function, device identifier and CRC are present and correct.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

The following constants are available for this function:

For mode:

  • MULTI_TOUCH_V2_BRICKLET_BOOTLOADER_MODE_BOOTLOADER = 0
  • MULTI_TOUCH_V2_BRICKLET_BOOTLOADER_MODE_FIRMWARE = 1
  • MULTI_TOUCH_V2_BRICKLET_BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • MULTI_TOUCH_V2_BRICKLET_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • MULTI_TOUCH_V2_BRICKLET_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4

For status:

  • MULTI_TOUCH_V2_BRICKLET_BOOTLOADER_STATUS_OK = 0
  • MULTI_TOUCH_V2_BRICKLET_BOOTLOADER_STATUS_INVALID_MODE = 1
  • MULTI_TOUCH_V2_BRICKLET_BOOTLOADER_STATUS_NO_CHANGE = 2
  • MULTI_TOUCH_V2_BRICKLET_BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
  • MULTI_TOUCH_V2_BRICKLET_BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
  • MULTI_TOUCH_V2_BRICKLET_BOOTLOADER_STATUS_CRC_MISMATCH = 5
pub fn MultiTouchV2Bricklet::get_bootloader_mode(&self) → ConvertingReceiver<u8>
Returns:
  • mode – Type: u8, Range: See constants

Returns the current bootloader mode, see MultiTouchV2Bricklet::set_bootloader_mode.

The following constants are available for this function:

For mode:

  • MULTI_TOUCH_V2_BRICKLET_BOOTLOADER_MODE_BOOTLOADER = 0
  • MULTI_TOUCH_V2_BRICKLET_BOOTLOADER_MODE_FIRMWARE = 1
  • MULTI_TOUCH_V2_BRICKLET_BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • MULTI_TOUCH_V2_BRICKLET_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • MULTI_TOUCH_V2_BRICKLET_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
pub fn MultiTouchV2Bricklet::set_write_firmware_pointer(&self, pointer: u32) → ConvertingReceiver<()>
Parameters:
  • pointer – Type: u32, Range: [0 to 232 - 1]

Sets the firmware pointer for MultiTouchV2Bricklet::write_firmware. The pointer has to be increased by chunks of size 64. The data is written to flash every 4 chunks (which equals to one page of size 256).

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

pub fn MultiTouchV2Bricklet::write_firmware(&self, data: [u8; 64]) → ConvertingReceiver<u8>
Parameters:
  • data – Type: [u8; 64], Range: [0 to 255]
Returns:
  • status – Type: u8, Range: [0 to 255]

Writes 64 Bytes of firmware at the position as written by MultiTouchV2Bricklet::set_write_firmware_pointer before. The firmware is written to flash every 4 chunks.

You can only write firmware in bootloader mode.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

pub fn MultiTouchV2Bricklet::set_status_led_config(&self, config: u8) → ConvertingReceiver<()>
Parameters:
  • config – Type: u8, Range: See constants

Sets the status LED configuration. By default the LED shows communication traffic between Brick and Bricklet, it flickers once for every 10 received data packets.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is will show heartbeat by default.

The following constants are available for this function:

For config:

  • MULTI_TOUCH_V2_BRICKLET_STATUS_LED_CONFIG_OFF = 0
  • MULTI_TOUCH_V2_BRICKLET_STATUS_LED_CONFIG_ON = 1
  • MULTI_TOUCH_V2_BRICKLET_STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • MULTI_TOUCH_V2_BRICKLET_STATUS_LED_CONFIG_SHOW_STATUS = 3
pub fn MultiTouchV2Bricklet::get_status_led_config(&self) → ConvertingReceiver<u8>
Returns:
  • config – Type: u8, Range: See constants

Returns the configuration as set by MultiTouchV2Bricklet::set_status_led_config

The following constants are available for this function:

For config:

  • MULTI_TOUCH_V2_BRICKLET_STATUS_LED_CONFIG_OFF = 0
  • MULTI_TOUCH_V2_BRICKLET_STATUS_LED_CONFIG_ON = 1
  • MULTI_TOUCH_V2_BRICKLET_STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • MULTI_TOUCH_V2_BRICKLET_STATUS_LED_CONFIG_SHOW_STATUS = 3
pub fn MultiTouchV2Bricklet::get_chip_temperature(&self) → ConvertingReceiver<i16>
Returns:
  • temperature – Type: i16, Range: [-215 to 215 - 1]

Returns the temperature in °C as measured inside the microcontroller. The value returned is not the ambient temperature!

The temperature is only proportional to the real temperature and it has bad accuracy. Practically it is only useful as an indicator for temperature changes.

pub fn MultiTouchV2Bricklet::reset(&self) → ConvertingReceiver<()>

Calling this function will reset the Bricklet. All configurations will be lost.

After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!

pub fn MultiTouchV2Bricklet::write_uid(&self, uid: u32) → ConvertingReceiver<()>
Parameters:
  • uid – Type: u32, Range: [0 to 232 - 1]

Writes a new UID into flash. If you want to set a new UID you have to decode the Base58 encoded UID string into an integer first.

We recommend that you use Brick Viewer to change the UID.

pub fn MultiTouchV2Bricklet::read_uid(&self) → ConvertingReceiver<u32>
Returns:
  • uid – Type: u32, Range: [0 to 232 - 1]

Returns the current UID as an integer. Encode as Base58 to get the usual string version.

pub fn MultiTouchV2Bricklet::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
  • hardware_version – Type: [u8; 3], Range: [0 to 255]
  • firmware_version – Type: [u8; 3], 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' 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 MultiTouchV2Bricklet::set_touch_state_callback_configuration(&self, period: u32, value_has_to_change: bool) → ConvertingReceiver<()>
Parameters:
  • period – Type: u32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
  • value_has_to_change – Type: bool, Default: false

The period is the period with which the MultiTouchV2Bricklet::get_touch_state_callback_receiver callback is triggered periodically. A value of 0 turns the callback off.

If the value has to change-parameter is set to true, the callback is only triggered after the value has changed. If the value didn't change within the period, the callback is triggered immediately on change.

If it is set to false, the callback is continuously triggered with the period, independent of the value.

pub fn MultiTouchV2Bricklet::get_touch_state_callback_configuration(&self) → ConvertingReceiver<TouchStateCallbackConfiguration>
Return Object:
  • period – Type: u32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
  • value_has_to_change – Type: bool, Default: false

Returns the callback configuration as set by MultiTouchV2Bricklet::set_touch_state_callback_configuration.

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 MultiTouchV2Bricklet::get_touch_state_callback_receiver(&self) → ConvertingCallbackReceiver<[bool; 13]>
Event:
  • state – Type: [bool; 13]

Receivers created with this function receive Touch State events.

Returns the current touch state, see MultiTouchV2Bricklet::get_touch_state for information about the state.

This callback is triggered every time the touch state changes with a given period (see MultiTouchV2Bricklet::set_touch_state_callback_configuration)

Constants

pub const MultiTouchV2Bricklet::DEVICE_IDENTIFIER

This constant is used to identify a Multi Touch Bricklet 2.0.

The MultiTouchV2Bricklet::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 MultiTouchV2Bricklet::DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Multi Touch Bricklet 2.0.