Software / API Bindings / C/C++ for Microcontrollers / API Reference and Examples / Bricklets / Servo Bricklet 2.0

C/C++ for Microcontrollers - Servo Bricklet 2.0¶

This is the description of the C/C++ for Microcontrollers API bindings for the Servo Bricklet 2.0. General information and technical specifications for the Servo Bricklet 2.0 are summarized in its hardware description.

An installation guide for the C/C++ for Microcontrollers API bindings is part of their general description.

Examples¶

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

Configuration¶

Download (example_configuration.c)

// This example is not self-contained.
// It requires usage of the example driver specific to your platform.
// See the HAL documentation.

#include "src/bindings/hal_common.h"
#include "src/bindings/bricklet_servo_v2.h"

void check(int rc, const char *msg);
void example_setup(TF_HAL *hal);
void example_loop(TF_HAL *hal);

static TF_ServoV2 s;

void example_setup(TF_HAL *hal) {
    // Create device object
    check(tf_servo_v2_create(&s, NULL, hal), "create device object");

    // Servo 1: Connected to port 0, period of 19.5ms, pulse width of 1 to 2ms
    //          and operating angle -100 to 100°
    check(tf_servo_v2_set_degree(&s, 0, -10000, 10000), "call set_degree");
    check(tf_servo_v2_set_pulse_width(&s, 0, 1000, 2000), "call set_pulse_width");
    check(tf_servo_v2_set_period(&s, 0, 19500), "call set_period");
    check(tf_servo_v2_set_motion_configuration(&s, 0, 500000, 1000,
                                               1000), "call set_motion_configuration"); // Full velocity with slow ac-/deceleration


    // Servo 2: Connected to port 5, period of 20ms, pulse width of 0.95 to 1.95ms
    //          and operating angle -90 to 90°
    check(tf_servo_v2_set_degree(&s, 5, -9000, 9000), "call set_degree");
    check(tf_servo_v2_set_pulse_width(&s, 5, 950, 1950), "call set_pulse_width");
    check(tf_servo_v2_set_period(&s, 5, 20000), "call set_period");
    check(tf_servo_v2_set_motion_configuration(&s, 5, 500000, 500000,
                                               500000), "call set_motion_configuration"); // Full velocity with full ac-/deceleration

    check(tf_servo_v2_set_position(&s, 0,
                                   10000), "call set_position"); // Set to most right position
    check(tf_servo_v2_set_enable(&s, 0, true), "call set_enable");

    check(tf_servo_v2_set_position(&s, 5,
                                   -9000), "call set_position"); // Set to most left position
    check(tf_servo_v2_set_enable(&s, 5, true), "call set_enable");
}

void example_loop(TF_HAL *hal) {
    // Poll for callbacks
    tf_hal_callback_tick(hal, 0);
}

Callback¶

Download (example_callback.c)

// This example is not self-contained.
// It requires usage of the example driver specific to your platform.
// See the HAL documentation.

#include "src/bindings/hal_common.h"
#include "src/bindings/bricklet_servo_v2.h"

void check(int rc, const char *msg);
void example_setup(TF_HAL *hal);
void example_loop(TF_HAL *hal);

// Use position reached callback to swing back and forth
static void position_reached_handler(TF_ServoV2 *device, uint16_t servo_channel,
                                     int16_t position, void *user_data) {
    (void)device; (void)user_data; // avoid unused parameter warning

    if (position == 9000) {
        tf_hal_printf("Position: 90°, going to -90°\n");
        tf_servo_v2_set_position(device, servo_channel, -9000);
    } else if (position == -9000) {
        tf_hal_printf("Position: -90°, going to 90°\n");
        tf_servo_v2_set_position(device, servo_channel, 9000);
    } else {
        tf_hal_printf("Error\n"); // Can only happen if another program sets position
    }
}

static TF_ServoV2 s;

void example_setup(TF_HAL *hal) {
    // Create device object
    check(tf_servo_v2_create(&s, NULL, hal), "create device object");

    // Register position reached callback to function position_reached_handler
    tf_servo_v2_register_position_reached_callback(&s,
                                                   position_reached_handler,
                                                   NULL);

    // Enable position reached callback
    check(tf_servo_v2_set_position_reached_callback_configuration(&s, 0,
                                                                  true), "call set_position_reached_callback_configuration");

    // Set velocity to 100°/s. This has to be smaller or equal to the
    // maximum velocity of the servo you are using, otherwise the position
    // reached callback will be called too early
    check(tf_servo_v2_set_motion_configuration(&s, 0, 10000, 500000,
                                               500000), "call set_motion_configuration");
    check(tf_servo_v2_set_position(&s, 0, 9000), "call set_position");
    check(tf_servo_v2_set_enable(&s, 0, true), "call set_enable");
}

void example_loop(TF_HAL *hal) {
    // Poll for callbacks
    tf_hal_callback_tick(hal, 0);
}

API¶

Most functions of the C/C++ bindings for microcontrollers return an error code (e_code).

Possible error codes are:

TF_E_OK = 0
TF_E_TIMEOUT = -1
TF_E_INVALID_PARAMETER = -2
TF_E_NOT_SUPPORTED = -3
TF_E_UNKNOWN_ERROR_CODE = -4
TF_E_STREAM_OUT_OF_SYNC = -5
TF_E_INVALID_CHAR_IN_UID = -6
TF_E_UID_TOO_LONG = -7
TF_E_UID_OVERFLOW = -8
TF_E_TOO_MANY_DEVICES = -9
TF_E_DEVICE_NOT_FOUND = -10
TF_E_WRONG_DEVICE_TYPE = -11
TF_E_LOCKED = -12
TF_E_PORT_NOT_FOUND = -13

(as defined in errors.h) as well as the errors returned from the hardware abstraction layer (HAL) that is used.

Use :cpp:func`tf_hal_strerror` (defined in the HAL's header file) to get an error string for an error code.

Data returned from the device, when a getter is called, is handled via output parameters. These parameters are labeled with the ret_ prefix. The bindings will not write to an output parameter if NULL or nullptr is passed. This can be used to ignore outputs that you are not interested in.

None of the functions listed below are thread-safe. See the API bindings description for details.

Every function of the Servo Brick API that has a servo_channel parameter can address a servo with the servo channel (0 to 9). If it is a setter function then multiple servos can be addressed at once with a bitmask for the servos, if the highest bit is set. For example: 1 will address servo 1, (1 << 1) | (1 << 5) | (1 << 15) will address servos 1 and 5. This allows to set configurations to several servos with one function call. It is guaranteed that the changes will take effect in the same PWM period for all servos you specified in the bitmask.

Basic Functions¶

int tf_servo_v2_create(TF_ServoV2 *servo_v2, const char *uid_or_port_name, TF_HAL *hal)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * uid – Type: const char * hal – Type: TF_HAL *
Returns:	e_code – Type: int

Creates the device object servo_v2 with the optional unique device ID or port name uid_or_port_name and adds it to the HAL hal:

TF_ServoV2 servo_v2;
tf_servo_v2_create(&servo_v2, NULL, &hal);

Normally uid_or_port_name can stay NULL. For more details about this see section UID or Port Name.

int tf_servo_v2_destroy(TF_ServoV2 *servo_v2)¶

Parameters:	servo_v2 – Type: TF_ServoV2 *
Returns:	e_code – Type: int

Removes the device object servo_v2 from its HAL and destroys it. The device object cannot be used anymore afterwards.

int tf_servo_v2_get_status(TF_ServoV2 *servo_v2, bool ret_enabled[10], int16_t ret_current_position[10], int16_t ret_current_velocity[10], uint16_t ret_current[10], uint16_t *ret_input_voltage)¶

Parameters:	servo_v2 – Type: TF_ServoV2 *
Output Parameters:	ret_enabled – Type: bool[10] ret_current_position – Type: int16_t[10], Unit: 1/100 °, Range: ? ret_current_velocity – Type: int16_t[10], Unit: 1/100 °/s, Range: [0 to 500000] ret_current – Type: uint16_t[10], Unit: 1 mA, Range: [0 to 2¹⁶ - 1] ret_input_voltage – Type: uint16_t, Unit: 1 mV, Range: [0 to 2¹⁶ - 1]
Returns:	e_code – Type: int

Returns the status information of the Servo Bricklet 2.0.

The status includes

for each channel if it is enabled or disabled,
for each channel the current position,
for each channel the current velocity,
for each channel the current usage and
the input voltage.

Please note that the position and the velocity is a snapshot of the current position and velocity of the servo in motion.

int tf_servo_v2_set_enable(TF_ServoV2 *servo_v2, uint16_t servo_channel, bool enable)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * servo_channel – Type: uint16_t, Range: [0 to 9, 2¹⁵ to 33791] enable – Type: bool, Default: false
Returns:	e_code – Type: int

Enables a servo channel (0 to 9). If a servo is enabled, the configured position, velocity, acceleration, etc. are applied immediately.

int tf_servo_v2_get_enabled(TF_ServoV2 *servo_v2, uint16_t servo_channel, bool *ret_enable)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * servo_channel – Type: uint16_t, Range: [0 to 9]
Output Parameters:	ret_enable – Type: bool, Default: false
Returns:	e_code – Type: int

Returns true if the specified servo channel is enabled, false otherwise.

int tf_servo_v2_set_position(TF_ServoV2 *servo_v2, uint16_t servo_channel, int16_t position)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * servo_channel – Type: uint16_t, Range: [0 to 9, 2¹⁵ to 33791] position – Type: int16_t, Unit: 1/100 °, Range: ?
Returns:	e_code – Type: int

Sets the position in °/100 for the specified servo channel.

The default range of the position is -9000 to 9000, but it can be specified according to your servo with tf_servo_v2_set_degree().

If you want to control a linear servo or RC brushless motor controller or similar with the Servo Brick, you can also define lengths or speeds with tf_servo_v2_set_degree().

int tf_servo_v2_get_position(TF_ServoV2 *servo_v2, uint16_t servo_channel, int16_t *ret_position)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * servo_channel – Type: uint16_t, Range: [0 to 9]
Output Parameters:	ret_position – Type: int16_t, Unit: 1/100 °, Range: ?
Returns:	e_code – Type: int

Returns the position of the specified servo channel as set by tf_servo_v2_set_position().

int tf_servo_v2_get_current_position(TF_ServoV2 *servo_v2, uint16_t servo_channel, int16_t *ret_position)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * servo_channel – Type: uint16_t, Range: [0 to 9]
Output Parameters:	ret_position – Type: int16_t, Unit: 1/100 °, Range: ?
Returns:	e_code – Type: int

Returns the current position of the specified servo channel. This may not be the value of tf_servo_v2_set_position() if the servo is currently approaching a position goal.

int tf_servo_v2_get_current_velocity(TF_ServoV2 *servo_v2, uint16_t servo_channel, uint16_t *ret_velocity)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * servo_channel – Type: uint16_t, Range: [0 to 9]
Output Parameters:	ret_velocity – Type: uint16_t, Unit: 1/100 °/s, Range: [0 to 500000]
Returns:	e_code – Type: int

Returns the current velocity of the specified servo channel. This may not be the velocity specified by tf_servo_v2_set_motion_configuration(). if the servo is currently approaching a velocity goal.

int tf_servo_v2_set_motion_configuration(TF_ServoV2 *servo_v2, uint16_t servo_channel, uint32_t velocity, uint32_t acceleration, uint32_t deceleration)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * servo_channel – Type: uint16_t, Range: [0 to 9, 2¹⁵ to 33791] velocity – Type: uint32_t, Unit: 1/100 °/s, Range: [0 to 500000], Default: 100000 acceleration – Type: uint32_t, Unit: 1/100 °/s², Range: [0 to 500000], Default: 50000 deceleration – Type: uint32_t, Unit: 1/100 °/s², Range: [0 to 500000], Default: 50000
Returns:	e_code – Type: int

Sets the maximum velocity of the specified servo channel in °/100s as well as the acceleration and deceleration in °/100s²

With a velocity of 0 °/100s the position will be set immediately (no velocity).

With an acc-/deceleration of 0 °/100s² the velocity will be set immediately (no acc-/deceleration).

int tf_servo_v2_get_motion_configuration(TF_ServoV2 *servo_v2, uint16_t servo_channel, uint32_t *ret_velocity, uint32_t *ret_acceleration, uint32_t *ret_deceleration)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * servo_channel – Type: uint16_t, Range: [0 to 9]
Output Parameters:	ret_velocity – Type: uint32_t, Unit: 1/100 °/s, Range: [0 to 500000], Default: 100000 ret_acceleration – Type: uint32_t, Unit: 1/100 °/s², Range: [0 to 500000], Default: 50000 ret_deceleration – Type: uint32_t, Unit: 1/100 °/s², Range: [0 to 500000], Default: 50000
Returns:	e_code – Type: int

Returns the motion configuration as set by tf_servo_v2_set_motion_configuration().

int tf_servo_v2_set_pulse_width(TF_ServoV2 *servo_v2, uint16_t servo_channel, uint32_t min, uint32_t max)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * servo_channel – Type: uint16_t, Range: [0 to 9, 2¹⁵ to 33791] min – Type: uint32_t, Unit: 1 µs, Range: [0 to 2³² - 1], Default: 1000 max – Type: uint32_t, Unit: 1 µs, Range: [0 to 2³² - 1], Default: 2000
Returns:	e_code – Type: int

Sets the minimum and maximum pulse width of the specified servo channel in µs.

Usually, servos are controlled with a PWM, whereby the length of the pulse controls the position of the servo. Every servo has different minimum and maximum pulse widths, these can be specified with this function.

If you have a datasheet for your servo that specifies the minimum and maximum pulse width, you should set the values accordingly. If your servo comes without any datasheet you have to find the values via trial and error.

Both values have a range from 1 to 65535 (unsigned 16-bit integer). The minimum must be smaller than the maximum.

The default values are 1000µs (1ms) and 2000µs (2ms) for minimum and maximum pulse width.

int tf_servo_v2_get_pulse_width(TF_ServoV2 *servo_v2, uint16_t servo_channel, uint32_t *ret_min, uint32_t *ret_max)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * servo_channel – Type: uint16_t, Range: [0 to 9]
Output Parameters:	ret_min – Type: uint32_t, Unit: 1 µs, Range: [0 to 2³² - 1], Default: 1000 ret_max – Type: uint32_t, Unit: 1 µs, Range: [0 to 2³² - 1], Default: 2000
Returns:	e_code – Type: int

Returns the minimum and maximum pulse width for the specified servo channel as set by tf_servo_v2_set_pulse_width().

int tf_servo_v2_set_degree(TF_ServoV2 *servo_v2, uint16_t servo_channel, int16_t min, int16_t max)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * servo_channel – Type: uint16_t, Range: [0 to 9, 2¹⁵ to 33791] min – Type: int16_t, Unit: 1/100 °, Range: [-2¹⁵ to 2¹⁵ - 1], Default: -9000 max – Type: int16_t, Unit: 1/100 °, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 9000
Returns:	e_code – Type: int

Sets the minimum and maximum degree for the specified servo channel (by default given as °/100).

This only specifies the abstract values between which the minimum and maximum pulse width is scaled. For example: If you specify a pulse width of 1000µs to 2000µs and a degree range of -90° to 90°, a call of tf_servo_v2_set_position() with 0 will result in a pulse width of 1500µs (-90° = 1000µs, 90° = 2000µs, etc.).

Possible usage:

The datasheet of your servo specifies a range of 200° with the middle position at 110°. In this case you can set the minimum to -9000 and the maximum to 11000.
You measure a range of 220° on your servo and you don't have or need a middle position. In this case you can set the minimum to 0 and the maximum to 22000.
You have a linear servo with a drive length of 20cm, In this case you could set the minimum to 0 and the maximum to 20000. Now you can set the Position with tf_servo_v2_set_position() with a resolution of cm/100. Also the velocity will have a resolution of cm/100s and the acceleration will have a resolution of cm/100s².
You don't care about units and just want the highest possible resolution. In this case you should set the minimum to -32767 and the maximum to 32767.
You have a brushless motor with a maximum speed of 10000 rpm and want to control it with a RC brushless motor controller. In this case you can set the minimum to 0 and the maximum to 10000. tf_servo_v2_set_position() now controls the rpm.

Both values have a possible range from -32767 to 32767 (signed 16-bit integer). The minimum must be smaller than the maximum.

The default values are -9000 and 9000 for the minimum and maximum degree.

int tf_servo_v2_get_degree(TF_ServoV2 *servo_v2, uint16_t servo_channel, int16_t *ret_min, int16_t *ret_max)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * servo_channel – Type: uint16_t, Range: [0 to 9]
Output Parameters:	ret_min – Type: int16_t, Unit: 1/100 °, Range: [-2¹⁵ to 2¹⁵ - 1], Default: -9000 ret_max – Type: int16_t, Unit: 1/100 °, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 9000
Returns:	e_code – Type: int

Returns the minimum and maximum degree for the specified servo channel as set by tf_servo_v2_set_degree().

int tf_servo_v2_set_period(TF_ServoV2 *servo_v2, uint16_t servo_channel, uint32_t period)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * servo_channel – Type: uint16_t, Range: [0 to 9, 2¹⁵ to 33791] period – Type: uint32_t, Unit: 1 µs, Range: [1 to 1000000], Default: 19500
Returns:	e_code – Type: int

Sets the period of the specified servo channel in µs.

Usually, servos are controlled with a PWM. Different servos expect PWMs with different periods. Most servos run well with a period of about 20ms.

If your servo comes with a datasheet that specifies a period, you should set it accordingly. If you don't have a datasheet and you have no idea what the correct period is, the default value (19.5ms) will most likely work fine.

The minimum possible period is 1µs and the maximum is 1000000µs.

The default value is 19.5ms (19500µs).

int tf_servo_v2_get_period(TF_ServoV2 *servo_v2, uint16_t servo_channel, uint32_t *ret_period)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * servo_channel – Type: uint16_t, Range: [0 to 9]
Output Parameters:	ret_period – Type: uint32_t, Unit: 1 µs, Range: [1 to 1000000], Default: 19500
Returns:	e_code – Type: int

Returns the period for the specified servo channel as set by tf_servo_v2_set_period().

int tf_servo_v2_get_servo_current(TF_ServoV2 *servo_v2, uint16_t servo_channel, uint16_t *ret_current)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * servo_channel – Type: uint16_t, Range: [0 to 9]
Output Parameters:	ret_current – Type: uint16_t, Unit: 1 mA, Range: [0 to 2¹⁶ - 1]
Returns:	e_code – Type: int

Returns the current consumption of the specified servo channel in mA.

int tf_servo_v2_set_servo_current_configuration(TF_ServoV2 *servo_v2, uint16_t servo_channel, uint8_t averaging_duration)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * servo_channel – Type: uint16_t, Range: [0 to 9, 2¹⁵ to 33791] averaging_duration – Type: uint8_t, Unit: 1 ms, Range: [1 to 255], Default: 255
Returns:	e_code – Type: int

Sets the averaging duration of the current measurement for the specified servo channel in ms.

int tf_servo_v2_get_servo_current_configuration(TF_ServoV2 *servo_v2, uint16_t servo_channel, uint8_t *ret_averaging_duration)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * servo_channel – Type: uint16_t, Range: [0 to 9]
Output Parameters:	ret_averaging_duration – Type: uint8_t, Unit: 1 ms, Range: [1 to 255], Default: 255
Returns:	e_code – Type: int

Returns the servo current configuration for the specified servo channel as set by tf_servo_v2_set_servo_current_configuration().

int tf_servo_v2_set_input_voltage_configuration(TF_ServoV2 *servo_v2, uint8_t averaging_duration)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * averaging_duration – Type: uint8_t, Unit: 1 ms, Range: [1 to 255], Default: 255
Returns:	e_code – Type: int

Sets the averaging duration of the input voltage measurement for the specified servo channel in ms.

int tf_servo_v2_get_input_voltage_configuration(TF_ServoV2 *servo_v2, uint8_t *ret_averaging_duration)¶

Parameters:	servo_v2 – Type: TF_ServoV2 *
Output Parameters:	ret_averaging_duration – Type: uint8_t, Unit: 1 ms, Range: [1 to 255], Default: 255
Returns:	e_code – Type: int

Returns the input voltage configuration as set by tf_servo_v2_set_input_voltage_configuration().

int tf_servo_v2_get_overall_current(TF_ServoV2 *servo_v2, uint16_t *ret_current)¶

Parameters:	servo_v2 – Type: TF_ServoV2 *
Output Parameters:	ret_current – Type: uint16_t, Unit: 1 mA, Range: [0 to 2¹⁶ - 1]
Returns:	e_code – Type: int

Returns the current consumption of all servos together in mA.

int tf_servo_v2_get_input_voltage(TF_ServoV2 *servo_v2, uint16_t *ret_voltage)¶

Parameters:	servo_v2 – Type: TF_ServoV2 *
Output Parameters:	ret_voltage – Type: uint16_t, Unit: 1 mV, Range: [0 to 2¹⁶ - 1]
Returns:	e_code – Type: int

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

Advanced Functions¶

int tf_servo_v2_set_current_calibration(TF_ServoV2 *servo_v2, const int16_t offset[10])¶

Parameters:	servo_v2 – Type: TF_ServoV2 * offset – Type: const int16_t[10], Unit: 1 mA, Range: [-2¹⁵ to 2¹⁵ - 1]
Returns:	e_code – Type: int

Sets an offset value (in mA) for each channel.

Note: On delivery the Servo Bricklet 2.0 is already calibrated.

int tf_servo_v2_get_current_calibration(TF_ServoV2 *servo_v2, int16_t ret_offset[10])¶

Parameters:	servo_v2 – Type: TF_ServoV2 *
Output Parameters:	ret_offset – Type: int16_t[10], Unit: 1 mA, Range: [-2¹⁵ to 2¹⁵ - 1]
Returns:	e_code – Type: int

Returns the current calibration as set by tf_servo_v2_set_current_calibration().

int tf_servo_v2_get_spitfp_error_count(TF_ServoV2 *servo_v2, uint32_t *ret_error_count_ack_checksum, uint32_t *ret_error_count_message_checksum, uint32_t *ret_error_count_frame, uint32_t *ret_error_count_overflow)¶

Parameters:	servo_v2 – Type: TF_ServoV2 *
Output Parameters:	ret_error_count_ack_checksum – Type: uint32_t, Range: [0 to 2³² - 1] ret_error_count_message_checksum – Type: uint32_t, Range: [0 to 2³² - 1] ret_error_count_frame – Type: uint32_t, Range: [0 to 2³² - 1] ret_error_count_overflow – Type: uint32_t, Range: [0 to 2³² - 1]
Returns:	e_code – Type: int

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.

int tf_servo_v2_set_status_led_config(TF_ServoV2 *servo_v2, uint8_t config)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * config – Type: uint8_t, Range: See constants, Default: 3
Returns:	e_code – Type: int

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:

TF_SERVO_V2_STATUS_LED_CONFIG_OFF = 0
TF_SERVO_V2_STATUS_LED_CONFIG_ON = 1
TF_SERVO_V2_STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
TF_SERVO_V2_STATUS_LED_CONFIG_SHOW_STATUS = 3

int tf_servo_v2_get_status_led_config(TF_ServoV2 *servo_v2, uint8_t *ret_config)¶

Parameters:	servo_v2 – Type: TF_ServoV2 *
Output Parameters:	ret_config – Type: uint8_t, Range: See constants, Default: 3
Returns:	e_code – Type: int

Returns the configuration as set by tf_servo_v2_set_status_led_config()

The following constants are available for this function:

For ret_config:

TF_SERVO_V2_STATUS_LED_CONFIG_OFF = 0
TF_SERVO_V2_STATUS_LED_CONFIG_ON = 1
TF_SERVO_V2_STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
TF_SERVO_V2_STATUS_LED_CONFIG_SHOW_STATUS = 3

int tf_servo_v2_get_chip_temperature(TF_ServoV2 *servo_v2, int16_t *ret_temperature)¶

Parameters:	servo_v2 – Type: TF_ServoV2 *
Output Parameters:	ret_temperature – Type: int16_t, Unit: 1 °C, Range: [-2¹⁵ to 2¹⁵ - 1]
Returns:	e_code – Type: int

Returns the temperature 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.

int tf_servo_v2_reset(TF_ServoV2 *servo_v2)¶

Parameters:	servo_v2 – Type: TF_ServoV2 *
Returns:	e_code – Type: int

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!

int tf_servo_v2_get_identity(TF_ServoV2 *servo_v2, char ret_uid[8], char ret_connected_uid[8], char *ret_position, uint8_t ret_hardware_version[3], uint8_t ret_firmware_version[3], uint16_t *ret_device_identifier)¶

Parameters:	servo_v2 – Type: TF_ServoV2 *
Output Parameters:	ret_uid – Type: char[8] ret_connected_uid – Type: char[8] ret_position – Type: char, Range: ['a' to 'h', 'z'] ret_hardware_version – Type: uint8_t[3] 0: major – Type: uint8_t, Range: [0 to 255] 1: minor – Type: uint8_t, Range: [0 to 255] 2: revision – Type: uint8_t, Range: [0 to 255] ret_firmware_version – Type: uint8_t[3] 0: major – Type: uint8_t, Range: [0 to 255] 1: minor – Type: uint8_t, Range: [0 to 255] 2: revision – Type: uint8_t, Range: [0 to 255] ret_device_identifier – Type: uint16_t, Range: [0 to 2¹⁶ - 1]
Returns:	e_code – Type: int

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). A Bricklet connected to an Isolator Bricklet is always at 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¶

int tf_servo_v2_set_position_reached_callback_configuration(TF_ServoV2 *servo_v2, uint16_t servo_channel, bool enabled)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * servo_channel – Type: uint16_t, Range: [0 to 9, 2¹⁵ to 33791] enabled – Type: bool, Default: false
Returns:	e_code – Type: int

Enable/Disable Position Reached callback.

int tf_servo_v2_get_position_reached_callback_configuration(TF_ServoV2 *servo_v2, uint16_t servo_channel, bool *ret_enabled)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * servo_channel – Type: uint16_t, Range: [0 to 9]
Output Parameters:	ret_enabled – Type: bool, Default: false
Returns:	e_code – Type: int

Returns the callback configuration as set by tf_servo_v2_set_position_reached_callback_configuration().

Callbacks¶

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the corresponding tf_servo_v2_register_*_callback function. The user_data passed to the registration function as well as the device that triggered the callback are passed to the registered callback handler.

Only one handler can be registered to a callback at the same time. To deregister a callback, call the tf_servo_v2_register_*_callback function with NULL as handler.

Note

Using callbacks for recurring events is preferred compared to using getters. Polling for a callback requires writing one byte only. See here Optimizing Performance.

Warning

Calling bindings function from inside a callback handler is not allowed. See here Thread safety.

int tf_servo_v2_register_position_reached_callback(TF_ServoV2 *servo_v2, TF_ServoV2_PositionReachedHandler handler, void *user_data)¶

void handler(TF_ServoV2 *servo_v2, uint16_t servo_channel, int16_t position, void *user_data)

Callback Parameters:	servo_v2 – Type: TF_ServoV2 * servo_channel – Type: uint16_t, Range: [0 to 9] position – Type: int16_t, Unit: 1/100 °, Range: ? user_data – Type: void *

This callback is triggered when a position set by tf_servo_v2_set_position() is reached. If the new position matches the current position then the callback is not triggered, because the servo didn't move. The parameters are the servo and the position that is reached.

You can enable this callback with tf_servo_v2_set_position_reached_callback_configuration().

Note

Since we can't get any feedback from the servo, this only works if the velocity (see tf_servo_v2_set_motion_configuration()) is set smaller or equal to the maximum velocity of the servo. Otherwise the servo will lag behind the control value and the callback will be triggered too early.

Virtual Functions¶

Virtual functions don't communicate with the device itself, but operate only on the API bindings device object.

int tf_servo_v2_get_response_expected(TF_ServoV2 *servo_v2, uint8_t function_id, bool *ret_response_expected)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * function_id – Type: uint8_t, Range: See constants
Output Parameters:	ret_response_expected – Type: bool
Returns:	e_code – Type: int

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 tf_servo_v2_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:

TF_SERVO_V2_FUNCTION_SET_ENABLE = 2
TF_SERVO_V2_FUNCTION_SET_POSITION = 4
TF_SERVO_V2_FUNCTION_SET_MOTION_CONFIGURATION = 8
TF_SERVO_V2_FUNCTION_SET_PULSE_WIDTH = 10
TF_SERVO_V2_FUNCTION_SET_DEGREE = 12
TF_SERVO_V2_FUNCTION_SET_PERIOD = 14
TF_SERVO_V2_FUNCTION_SET_SERVO_CURRENT_CONFIGURATION = 17
TF_SERVO_V2_FUNCTION_SET_INPUT_VOLTAGE_CONFIGURATION = 19
TF_SERVO_V2_FUNCTION_SET_CURRENT_CALIBRATION = 23
TF_SERVO_V2_FUNCTION_SET_POSITION_REACHED_CALLBACK_CONFIGURATION = 25
TF_SERVO_V2_FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
TF_SERVO_V2_FUNCTION_SET_STATUS_LED_CONFIG = 239
TF_SERVO_V2_FUNCTION_RESET = 243
TF_SERVO_V2_FUNCTION_WRITE_UID = 248

int tf_servo_v2_set_response_expected(TF_ServoV2 *servo_v2, uint8_t function_id, bool response_expected)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * function_id – Type: uint8_t, Range: See constants response_expected – Type: bool
Returns:	e_code – Type: int

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.

The following constants are available for this function:

For function_id:

TF_SERVO_V2_FUNCTION_SET_ENABLE = 2
TF_SERVO_V2_FUNCTION_SET_POSITION = 4
TF_SERVO_V2_FUNCTION_SET_MOTION_CONFIGURATION = 8
TF_SERVO_V2_FUNCTION_SET_PULSE_WIDTH = 10
TF_SERVO_V2_FUNCTION_SET_DEGREE = 12
TF_SERVO_V2_FUNCTION_SET_PERIOD = 14
TF_SERVO_V2_FUNCTION_SET_SERVO_CURRENT_CONFIGURATION = 17
TF_SERVO_V2_FUNCTION_SET_INPUT_VOLTAGE_CONFIGURATION = 19
TF_SERVO_V2_FUNCTION_SET_CURRENT_CALIBRATION = 23
TF_SERVO_V2_FUNCTION_SET_POSITION_REACHED_CALLBACK_CONFIGURATION = 25
TF_SERVO_V2_FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
TF_SERVO_V2_FUNCTION_SET_STATUS_LED_CONFIG = 239
TF_SERVO_V2_FUNCTION_RESET = 243
TF_SERVO_V2_FUNCTION_WRITE_UID = 248

int tf_servo_v2_set_response_expected_all(TF_ServoV2 *servo_v2, bool response_expected)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * response_expected – Type: bool
Returns:	e_code – Type: int

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

Internal Functions¶

Internal functions are used for maintenance tasks such as flashing a new firmware of changing the UID of a Bricklet. These task should be performed using Brick Viewer instead of using the internal functions directly.

int tf_servo_v2_set_bootloader_mode(TF_ServoV2 *servo_v2, uint8_t mode, uint8_t *ret_status)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * mode – Type: uint8_t, Range: See constants
Output Parameters:	ret_status – Type: uint8_t, Range: See constants
Returns:	e_code – Type: int

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:

TF_SERVO_V2_BOOTLOADER_MODE_BOOTLOADER = 0
TF_SERVO_V2_BOOTLOADER_MODE_FIRMWARE = 1
TF_SERVO_V2_BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
TF_SERVO_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
TF_SERVO_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4

For ret_status:

TF_SERVO_V2_BOOTLOADER_STATUS_OK = 0
TF_SERVO_V2_BOOTLOADER_STATUS_INVALID_MODE = 1
TF_SERVO_V2_BOOTLOADER_STATUS_NO_CHANGE = 2
TF_SERVO_V2_BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
TF_SERVO_V2_BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
TF_SERVO_V2_BOOTLOADER_STATUS_CRC_MISMATCH = 5

int tf_servo_v2_get_bootloader_mode(TF_ServoV2 *servo_v2, uint8_t *ret_mode)¶

Parameters:	servo_v2 – Type: TF_ServoV2 *
Output Parameters:	ret_mode – Type: uint8_t, Range: See constants
Returns:	e_code – Type: int

Returns the current bootloader mode, see tf_servo_v2_set_bootloader_mode().

The following constants are available for this function:

For ret_mode:

TF_SERVO_V2_BOOTLOADER_MODE_BOOTLOADER = 0
TF_SERVO_V2_BOOTLOADER_MODE_FIRMWARE = 1
TF_SERVO_V2_BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
TF_SERVO_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
TF_SERVO_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4

int tf_servo_v2_set_write_firmware_pointer(TF_ServoV2 *servo_v2, uint32_t pointer)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * pointer – Type: uint32_t, Unit: 1 B, Range: [0 to 2³² - 1]
Returns:	e_code – Type: int

Sets the firmware pointer for tf_servo_v2_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.

int tf_servo_v2_write_firmware(TF_ServoV2 *servo_v2, const uint8_t data[64], uint8_t *ret_status)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * data – Type: const uint8_t[64], Range: [0 to 255]
Output Parameters:	ret_status – Type: uint8_t, Range: [0 to 255]
Returns:	e_code – Type: int

Writes 64 Bytes of firmware at the position as written by tf_servo_v2_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.

int tf_servo_v2_write_uid(TF_ServoV2 *servo_v2, uint32_t uid)¶

Parameters:	servo_v2 – Type: TF_ServoV2 * uid – Type: uint32_t, Range: [0 to 2³² - 1]
Returns:	e_code – Type: int

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.

int tf_servo_v2_read_uid(TF_ServoV2 *servo_v2, uint32_t *ret_uid)¶

Parameters:	servo_v2 – Type: TF_ServoV2 *
Output Parameters:	ret_uid – Type: uint32_t, Range: [0 to 2³² - 1]
Returns:	e_code – Type: int

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

Constants¶

TF_SERVO_V2_DEVICE_IDENTIFIER¶

This constant is used to identify a Servo Bricklet 2.0.

The functions tf_servo_v2_get_identity() and tf_hal_get_device_info() have a device_identifier output parameter to specify the Brick's or Bricklet's type.

TF_SERVO_V2_DEVICE_DISPLAY_NAME¶: This constant represents the human readable name of a Servo Bricklet 2.0.