Rust - DC Brick

This is the description of the Rust API bindings for the DC Brick. General information and technical specifications for the DC Brick 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).

Configuration

Download (example_configuration.rs)

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

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

const HOST: &str = "localhost";
const PORT: u16 = 4223;
const UID: &str = "XXYYZZ"; // Change XXYYZZ to the UID of your DC Brick.

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

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

    dc.set_drive_mode(DC_BRICK_DRIVE_MODE_DRIVE_COAST);
    dc.set_pwm_frequency(10000); // Use PWM frequency of 10kHz
    dc.set_acceleration(5000); // Slow acceleration
    dc.set_velocity(32767); // Full speed forward
    dc.enable(); // Enable motor power

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

Callback

Download (example_callback.rs)

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

const HOST: &str = "127.0.0.1";
const PORT: u16 = 4223;
const UID: &str = "XXYYZZ"; // Change XXYYZZ to the UID of your DC Brick

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

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

    // The acceleration has to be smaller or equal to the maximum
    // acceleration of the DC motor, otherwise the velocity reached
    // callback will be called too early
    dc.set_acceleration(5000); // Slow acceleration
    dc.set_velocity(32767); // Full speed forward

    let velocity_reached_receiver = dc.get_velocity_reached_callback_receiver();

    // Spawn thread to handle received callback messages. This thread ends when the dc
    // is dropped, so there is no need for manual cleanup.
    let dc_copy = dc.clone(); //Device objects don't implement Sync, so they can't be shared between threads (by reference). So clone the device and move the copy.
    thread::spawn(move || {
        for velocity_reached in velocity_reached_receiver {
            if velocity_reached == 32767 {
                println!("Velocity: Full speed forward, now turning backward");
                dc_copy.set_velocity(-32767);
            } else if velocity_reached == -32767 {
                println!("Velocity: Full speed backward, now turning forward");
                dc_copy.set_velocity(32767);
            } else {
                //can only happen if another program sets velocity
                panic!("Error");
            }
        }
    });

    // Enable motor power
    dc.enable();

    println!("Press enter to exit.");
    let mut _input = String::new();
    io::stdin().read_line(&mut _input)?;
    dc.disable(); // Disable motor power
    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 DcBrick::new(uid: &str, ip_connection: &IpConnection) → DcBrick

Creates a new DcBrick 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 DcBrick::set_velocity(&self, velocity: i16) → ConvertingReceiver<()>

Sets the velocity of the motor. Whereas -32767 is full speed backward, 0 is stop and 32767 is full speed forward. Depending on the acceleration (see DcBrick::set_acceleration), the motor is not immediately brought to the velocity but smoothly accelerated.

The velocity describes the duty cycle of the PWM with which the motor is controlled, e.g. a velocity of 3277 sets a PWM with a 10% duty cycle. You can not only control the duty cycle of the PWM but also the frequency, see DcBrick::set_pwm_frequency.

The default velocity is 0.

pub fn DcBrick::get_velocity(&self) → ConvertingReceiver<i16>

Returns the velocity as set by DcBrick::set_velocity.

pub fn DcBrick::get_current_velocity(&self) → ConvertingReceiver<i16>

Returns the current velocity of the motor. This value is different from DcBrick::get_velocity whenever the motor is currently accelerating to a goal set by DcBrick::set_velocity.

pub fn DcBrick::set_acceleration(&self, acceleration: u16) → ConvertingReceiver<()>

Sets the acceleration of the motor. It is given in velocity/s. An acceleration of 10000 means, that every second the velocity is increased by 10000 (or about 30% duty cycle).

For example: If the current velocity is 0 and you want to accelerate to a velocity of 16000 (about 50% duty cycle) in 10 seconds, you should set an acceleration of 1600.

If acceleration is set to 0, there is no speed ramping, i.e. a new velocity is immediately given to the motor.

The default acceleration is 10000.

pub fn DcBrick::get_acceleration(&self) → ConvertingReceiver<u16>

Returns the acceleration as set by DcBrick::set_acceleration.

pub fn DcBrick::full_brake(&self) → ConvertingReceiver<()>

Executes an active full brake.

Warning

This function is for emergency purposes, where an immediate brake is necessary. Depending on the current velocity and the strength of the motor, a full brake can be quite violent.

Call DcBrick::set_velocity with 0 if you just want to stop the motor.

pub fn DcBrick::enable(&self) → ConvertingReceiver<()>

Enables the driver chip. The driver parameters can be configured (velocity, acceleration, etc) before it is enabled.

pub fn DcBrick::disable(&self) → ConvertingReceiver<()>

Disables the driver chip. The configurations are kept (velocity, acceleration, etc) but the motor is not driven until it is enabled again.

pub fn DcBrick::is_enabled(&self) → ConvertingReceiver<bool>

Returns true if the driver chip is enabled, false otherwise.

Advanced Functions

pub fn DcBrick::set_pwm_frequency(&self, frequency: u16) → ConvertingReceiver<()>

Sets the frequency (in Hz) of the PWM with which the motor is driven. The possible range of the frequency is 1-20000Hz. Often a high frequency is less noisy and the motor runs smoother. However, with a low frequency there are less switches and therefore fewer switching losses. Also with most motors lower frequencies enable higher torque.

If you have no idea what all this means, just ignore this function and use the default frequency, it will very likely work fine.

The default frequency is 15 kHz.

pub fn DcBrick::get_pwm_frequency(&self) → ConvertingReceiver<u16>

Returns the PWM frequency (in Hz) as set by DcBrick::set_pwm_frequency.

pub fn DcBrick::get_stack_input_voltage(&self) → ConvertingReceiver<u16>

Returns the stack input voltage in mV. The stack input voltage is the voltage that is supplied via the stack, i.e. it is given by a Step-Down or Step-Up Power Supply.

pub fn DcBrick::get_external_input_voltage(&self) → ConvertingReceiver<u16>

Returns the external input voltage in mV. The external input voltage is given via the black power input connector on the DC Brick.

If there is an external input voltage and a stack input voltage, the motor will be driven by the external input voltage. If there is only a stack voltage present, the motor will be driven by this voltage.

Warning

This means, if you have a high stack voltage and a low external voltage, the motor will be driven with the low external voltage. If you then remove the external connection, it will immediately be driven by the high stack voltage.

pub fn DcBrick::get_current_consumption(&self) → ConvertingReceiver<u16>

Returns the current consumption of the motor in mA.

pub fn DcBrick::set_drive_mode(&self, mode: u8) → ConvertingReceiver<()>

Sets the drive mode. Possible modes are:

  • 0 = Drive/Brake
  • 1 = Drive/Coast

These modes are different kinds of motor controls.

In Drive/Brake mode, the motor is always either driving or braking. There is no freewheeling. Advantages are: A more linear correlation between PWM and velocity, more exact accelerations and the possibility to drive with slower velocities.

In Drive/Coast mode, the motor is always either driving or freewheeling. Advantages are: Less current consumption and less demands on the motor and driver chip.

The default value is 0 = Drive/Brake.

The following constants are available for this function:

  • DC_BRICK_DRIVE_MODE_DRIVE_BRAKE = 0
  • DC_BRICK_DRIVE_MODE_DRIVE_COAST = 1
pub fn DcBrick::get_drive_mode(&self) → ConvertingReceiver<u8>

Returns the drive mode, as set by DcBrick::set_drive_mode.

The following constants are available for this function:

  • DC_BRICK_DRIVE_MODE_DRIVE_BRAKE = 0
  • DC_BRICK_DRIVE_MODE_DRIVE_COAST = 1
pub fn DcBrick::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 DcBrick::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 DcBrick::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 DcBrick::set_response_expected for the list of function ID constants available for this function.

pub fn DcBrick::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:

  • DC_BRICK_FUNCTION_SET_VELOCITY = 1
  • DC_BRICK_FUNCTION_SET_ACCELERATION = 4
  • DC_BRICK_FUNCTION_SET_PWM_FREQUENCY = 6
  • DC_BRICK_FUNCTION_FULL_BRAKE = 8
  • DC_BRICK_FUNCTION_ENABLE = 12
  • DC_BRICK_FUNCTION_DISABLE = 13
  • DC_BRICK_FUNCTION_SET_MINIMUM_VOLTAGE = 15
  • DC_BRICK_FUNCTION_SET_DRIVE_MODE = 17
  • DC_BRICK_FUNCTION_SET_CURRENT_VELOCITY_PERIOD = 19
  • DC_BRICK_FUNCTION_SET_SPITFP_BAUDRATE_CONFIG = 231
  • DC_BRICK_FUNCTION_SET_SPITFP_BAUDRATE = 234
  • DC_BRICK_FUNCTION_ENABLE_STATUS_LED = 238
  • DC_BRICK_FUNCTION_DISABLE_STATUS_LED = 239
  • DC_BRICK_FUNCTION_RESET = 243
pub fn DcBrick::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 DcBrick::set_spitfp_baudrate_config(&self, enable_dynamic_baudrate: bool, minimum_dynamic_baudrate: u32) → ConvertingReceiver<()>

The SPITF protocol can be used with a dynamic baudrate. If the dynamic baudrate is enabled, the Brick will try to adapt the baudrate for the communication between Bricks and Bricklets according to the amount of data that is transferred.

The baudrate will be increased exponentially if lots of data is send/received and decreased linearly if little data is send/received.

This lowers the baudrate in applications where little data is transferred (e.g. a weather station) and increases the robustness. If there is lots of data to transfer (e.g. Thermal Imaging Bricklet) it automatically increases the baudrate as needed.

In cases where some data has to transferred as fast as possible every few seconds (e.g. RS485 Bricklet with a high baudrate but small payload) you may want to turn the dynamic baudrate off to get the highest possible performance.

The maximum value of the baudrate can be set per port with the function DcBrick::set_spitfp_baudrate. If the dynamic baudrate is disabled, the baudrate as set by DcBrick::set_spitfp_baudrate will be used statically.

The minimum dynamic baudrate has a value range of 400000 to 2000000 baud.

By default dynamic baudrate is enabled and the minimum dynamic baudrate is 400000.

New in version 2.3.5 (Firmware).

pub fn DcBrick::get_spitfp_baudrate_config(&self) → ConvertingReceiver<SpitfpBaudrateConfig>

Returns the baudrate config, see DcBrick::set_spitfp_baudrate_config.

New in version 2.3.5 (Firmware).

pub fn DcBrick::get_send_timeout_count(&self, communication_method: u8) → ConvertingReceiver<u32>

Returns the timeout count for the different communication methods.

The methods 0-2 are available for all Bricks, 3-7 only for Master Bricks.

This function is mostly used for debugging during development, in normal operation the counters should nearly always stay at 0.

The following constants are available for this function:

  • DC_BRICK_COMMUNICATION_METHOD_NONE = 0
  • DC_BRICK_COMMUNICATION_METHOD_USB = 1
  • DC_BRICK_COMMUNICATION_METHOD_SPI_STACK = 2
  • DC_BRICK_COMMUNICATION_METHOD_CHIBI = 3
  • DC_BRICK_COMMUNICATION_METHOD_RS485 = 4
  • DC_BRICK_COMMUNICATION_METHOD_WIFI = 5
  • DC_BRICK_COMMUNICATION_METHOD_ETHERNET = 6
  • DC_BRICK_COMMUNICATION_METHOD_WIFI_V2 = 7

New in version 2.3.3 (Firmware).

pub fn DcBrick::set_spitfp_baudrate(&self, bricklet_port: char, baudrate: u32) → ConvertingReceiver<()>

Sets the baudrate for a specific Bricklet port ('a' - 'd'). The baudrate can be in the range 400000 to 2000000.

If you want to increase the throughput of Bricklets you can increase the baudrate. If you get a high error count because of high interference (see DcBrick::get_spitfp_error_count) you can decrease the baudrate.

If the dynamic baudrate feature is enabled, the baudrate set by this function corresponds to the maximum baudrate (see DcBrick::set_spitfp_baudrate_config).

Regulatory testing is done with the default baudrate. If CE compatibility or similar is necessary in you applications we recommend to not change the baudrate.

The default baudrate for all ports is 1400000.

New in version 2.3.3 (Firmware).

pub fn DcBrick::get_spitfp_baudrate(&self, bricklet_port: char) → ConvertingReceiver<u32>

Returns the baudrate for a given Bricklet port, see DcBrick::set_spitfp_baudrate.

New in version 2.3.3 (Firmware).

pub fn DcBrick::get_spitfp_error_count(&self, bricklet_port: char) → ConvertingReceiver<SpitfpErrorCount>

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 Brick side. All Bricklets have a similar function that returns the errors on the Bricklet side.

New in version 2.3.3 (Firmware).

pub fn DcBrick::enable_status_led(&self) → ConvertingReceiver<()>

Enables the status LED.

The status LED is the blue LED next to the USB connector. If enabled is is on and it flickers if data is transfered. If disabled it is always off.

The default state is enabled.

New in version 2.3.1 (Firmware).

pub fn DcBrick::disable_status_led(&self) → ConvertingReceiver<()>

Disables the status LED.

The status LED is the blue LED next to the USB connector. If enabled is is on and it flickers if data is transfered. If disabled it is always off.

The default state is enabled.

New in version 2.3.1 (Firmware).

pub fn DcBrick::is_status_led_enabled(&self) → ConvertingReceiver<bool>

Returns true if the status LED is enabled, false otherwise.

New in version 2.3.1 (Firmware).

pub fn DcBrick::get_protocol1_bricklet_name(&self, port: char) → ConvertingReceiver<Protocol1BrickletName>

Returns the firmware and protocol version and the name of the Bricklet for a given port.

This functions sole purpose is to allow automatic flashing of v1.x.y Bricklet plugins.

pub fn DcBrick::get_chip_temperature(&self) → ConvertingReceiver<i16>

Returns the temperature in °C/10 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 an accuracy of +-15%. Practically it is only useful as an indicator for temperature changes.

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

Calling this function will reset the Brick. Calling this function on a Brick inside of a stack will reset the whole stack.

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

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

Returns the UID, the UID where the Brick is connected to, the position, the hardware and firmware version as well as the device identifier.

The position can be '0'-'8' (stack position).

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

Callback Configuration Functions

pub fn DcBrick::set_minimum_voltage(&self, voltage: u16) → ConvertingReceiver<()>

Sets the minimum voltage in mV, below which the DcBrick::get_under_voltage_callback_receiver callback is triggered. The minimum possible value that works with the DC Brick is 6V. You can use this function to detect the discharge of a battery that is used to drive the motor. If you have a fixed power supply, you likely do not need this functionality.

The default value is 6V.

pub fn DcBrick::get_minimum_voltage(&self) → ConvertingReceiver<u16>

Returns the minimum voltage as set by DcBrick::set_minimum_voltage

pub fn DcBrick::set_current_velocity_period(&self, period: u16) → ConvertingReceiver<()>

Sets a period in ms with which the DcBrick::get_current_velocity_callback_receiver callback is triggered. A period of 0 turns the callback off.

The default value is 0.

pub fn DcBrick::get_current_velocity_period(&self) → ConvertingReceiver<u16>

Returns the period as set by DcBrick::set_current_velocity_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 DcBrick::get_under_voltage_callback_receiver(&self) → ConvertingCallbackReceiver<u16>

Receivers created with this function receive Under Voltage events.

This callback is triggered when the input voltage drops below the value set by DcBrick::set_minimum_voltage. The received variable is the current voltage given in mV.
pub fn DcBrick::get_emergency_shutdown_callback_receiver(&self) → ConvertingCallbackReceiver<()>

Receivers created with this function receive Emergency Shutdown events.

This callback is triggered if either the current consumption is too high (above 5A) or the temperature of the driver chip is too high (above 175°C). These two possibilities are essentially the same, since the temperature will reach this threshold immediately if the motor consumes too much current. In case of a voltage below 3.3V (external or stack) this callback is triggered as well.

If this callback is triggered, the driver chip gets disabled at the same time. That means, DcBrick::enable has to be called to drive the motor again.

Note

This callback only works in Drive/Brake mode (see DcBrick::set_drive_mode). In Drive/Coast mode it is unfortunately impossible to reliably read the overcurrent/overtemperature signal from the driver chip.

pub fn DcBrick::get_velocity_reached_callback_receiver(&self) → ConvertingCallbackReceiver<i16>

Receivers created with this function receive Velocity Reached events.

This callback is triggered whenever a set velocity is reached. For example: If a velocity of 0 is present, acceleration is set to 5000 and velocity to 10000, the DcBrick::get_velocity_reached_callback_receiver callback will be triggered after about 2 seconds, when the set velocity is actually reached.

Note

Since we can't get any feedback from the DC motor, this only works if the acceleration (see DcBrick::set_acceleration) is set smaller or equal to the maximum acceleration of the motor. Otherwise the motor will lag behind the control value and the callback will be triggered too early.

pub fn DcBrick::get_current_velocity_callback_receiver(&self) → ConvertingCallbackReceiver<i16>

Receivers created with this function receive Current Velocity events.

This callback is triggered with the period that is set by DcBrick::set_current_velocity_period. The received variable is the current velocity used by the motor.

The DcBrick::get_current_velocity_callback_receiver callback is only triggered after the set period if there is a change in the velocity.

Constants

DcBrick::DEVICE_IDENTIFIER

This constant is used to identify a DC Brick.

The DcBrick::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.

DcBrick::DEVICE_DISPLAY_NAME

This constant represents the human readable name of a DC Brick.