aruna::driver::Dshot Class Reference

#include <Dshot.h>

Inheritance diagram for aruna::driver::Dshot:

Collaboration diagram for aruna::driver::Dshot:

Public Member Functions
	Dshot (uint32_t speed_hz=150000, bool bidirectional=false)
	Dshot parent object. More...
uint32_t	get_frequency ()
	get frequency of the driver More...
err_t	set_speed (int16_t speed)
	Set speed, use negative values to rotate in the other direction if bidirectional is enabled. More...
bool	get_bidirectional ()
	Is this Dshot driver birectional (can spin both ways) More...
void	set_bidirectional (bool is_bidirectional)
	Set bidirectional property of the driver. More...
void	arm_ESC ()
	Call the function after the constructor to arm the ESC. More...
	~Dshot ()
Public Member Functions inherited from aruna::movement::Actuator
	Actuator (axis_mask_t axis=axis_mask_t::NONE)
	Actuator object, used by the movement module for vehicle movement. More...
virtual	~Actuator ()
err_t	set_axis (axis_mask_t new_axis)
	Set the axis that this Actuator is capable in moving in. More...
axis_mask_t	get_axis ()
	get the movement modes that this driver supports. More...
err_t	set (axis_mask_t axisMask, int16_t speed)
	Set the speed of the motors directly. More...
uint16_t	get_speed ()
	Get the current speed of Actuator. More...

Protected Attributes
uint16_t	T0H_ns
uint16_t	T1H_ns
uint16_t	T0L_ns
uint16_t	T1L_ns

Private Member Functions
void	add_CRC (uint16_t &bits)
	add CRC to end of bit stream. More...
uint16_t	create_dshotFrame (uint16_t speed, uint8_t telemetry)
	craft dshot package More...
err_t	_set (movement::axis_mask_t axisMask, int16_t speed) override
	Implementation of axis movement, this function is called from set(...). More...
err_t	write_frame_continuous (uint16_t dshot_frame)
	Write set Dshot frame continuously on the bus. More...
virtual err_t	_write_frame_continuous (uint16_t dshot_frame)=0
	Write set Dshot frame continuously on the bus. More...

Private Attributes
bool	_continues_write = false
pthread_mutex_t	write_mut
const uint32_t	frequency
bool	bidirectional

Additional Inherited Members
Public Attributes inherited from aruna::movement::Actuator
err_t	startup_error = err_t::NOT_STARTED
	error when constructing gets put here, read before usage. More...
Static Protected Member Functions inherited from aruna::movement::Actuator
static double	convert_range (uint16_t input, float range_max=100.f, float range_min=0.f)
	Convert uint16 to a new range. More...

Detailed Description

Definition at line 13 of file Dshot.h.

Constructor & Destructor Documentation

Dshot()

Dshot::Dshot	(	uint32_t	speed_hz = 150000,
		bool	bidirectional = false
	)

Dshot parent object.

Parameters

speed_hz	speed of the protocol
bidirectional	set to true if the ESC is bidirectional.

Definition at line 13 of file Dshot.cpp.

                                                 : frequency(speed_hz), bidirectional(bidirectional) {

    uint32_t max_ns = (1.f / (float) speed_hz) * 1000000000;

    const static float T0H_percentage = 0.375;
    const static float T1H_percentage = 0.75;
    const static float T0L_percentage = 1 - T0H_percentage;
    const static float T1L_percentage = 1 - T1H_percentage;

    T0H_ns = max_ns * T0H_percentage;
    T1H_ns = max_ns * T1H_percentage;
    T0L_ns = max_ns * T0L_percentage;
    T1L_ns = max_ns * T1L_percentage;

    pthread_mutexattr_t swm_att;
    pthread_mutexattr_init(&swm_att);
    pthread_mutex_init(&write_mut, &swm_att);
    pthread_mutexattr_destroy(&swm_att);

}

~Dshot()

Dshot::~Dshot

(

)

Definition at line 116 of file Dshot.cpp.

              {
    pthread_mutex_destroy(&write_mut);
}

Member Function Documentation

_set()

aruna::err_t Dshot::_set ( movement::axis_mask_t  axisMask, int16_t  speed  )

overrideprivatevirtual

Implementation of axis movement, this function is called from set(...).

Only gets called when axisMask match axis of Actuator.

Parameters

axisMask	axis (can be multiple) to set speed to.
speed	desired speed.

Returns

err_t::OK if successful, others when not...

Implements aruna::movement::Actuator.

Definition at line 35 of file Dshot.cpp.

                                                                  {
   return set_speed(speed);
}

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_write_frame_continuous()

virtual err_t aruna::driver::Dshot::_write_frame_continuous ( uint16_t  dshot_frame )

privatepure virtual

Write set Dshot frame continuously on the bus.

Parameters

dshot_frame

Dhsot frame to send, already encoded in bits

Returns

• err_t::OK success
• err_t::FAIL on failure.

Implemented in aruna::driver::ESP32_RMT_Dshot.

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add_CRC()

void Dshot::add_CRC ( uint16_t &  bits )

private

add CRC to end of bit stream.

Parameters

bits	to add CRC on

Definition at line 62 of file Dshot.cpp.

                                  {
    uint8_t csum = 0;
    uint16_t csum_data = bits >> 4;
    for (uint8_t i = 0; i < 3; i++) {
        csum ^= csum_data;
        csum_data >>= 4;
    }
    csum &= 0xf;
    bits |= csum;
}

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arm_ESC()

void Dshot::arm_ESC

(

)

Call the function after the constructor to arm the ESC.

set_speed() will not work without arming the ESC.

Definition at line 83 of file Dshot.cpp.

                    {

//    arm ESC
    uint16_t start_value = 48;
    uint8_t step = 50;
    uint8_t amount_of_steps = 40;

//    up hill
    for (int i = 0; i < amount_of_steps; ++i) {
        write_frame_continuous(create_dshotFrame((step * i) + start_value, 0));
        usleep(1);
    }
//    down hill
    for (int i = amount_of_steps - 1; i > -1; --i) {
        write_frame_continuous(create_dshotFrame((step * i) + start_value, 0));
        usleep(1);
    }
//    stay low for a little while
    write_frame_continuous(create_dshotFrame(start_value, 0));
    usleep(150);

    set_speed(0);

}

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create_dshotFrame()

uint16_t Dshot::create_dshotFrame ( uint16_t  speed, uint8_t  telemetry  )

private

craft dshot package

Parameters

speed	keep between 48-2047
telemetry	0 or 1

Returns

dshot bit package with CRC

Definition at line 75 of file Dshot.cpp.

                                                                   {
    uint16_t bit_frame = 0;
    bit_frame = speed << 5;
    bit_frame |= telemetry << 4;
    add_CRC(bit_frame);
    return bit_frame;
}

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get_bidirectional()

bool Dshot::get_bidirectional

(

)

Is this Dshot driver birectional (can spin both ways)

Returns

true if is birectional, false if not.

Definition at line 124 of file Dshot.cpp.

                              {
    return bidirectional;
}

get_frequency()

uint32_t Dshot::get_frequency

(

)

get frequency of the driver

Returns

frequency in hertz.

Definition at line 120 of file Dshot.cpp.

                              {
    return frequency;
}

set_bidirectional()

void Dshot::set_bidirectional

(

bool

is_bidirectional

)

Set bidirectional property of the driver.

Parameters

is_bidirectional

true is bidirectional, false if single directional.

Definition at line 128 of file Dshot.cpp.

                                                   {
    bidirectional = is_bidirectional;
}

set_speed()

err_t Dshot::set_speed

(

int16_t

speed

)

Set speed, use negative values to rotate in the other direction if bidirectional is enabled.

Parameters

speed

speed

Returns

• err_t::OK success
• err_t::FAIL on failure.

Definition at line 39 of file Dshot.cpp.

                                    {
    const static uint16_t MAX_VALUE = 2047;
    const static uint16_t MIN_VALUE = 48;
    const static uint16_t MID_VALUE = (MAX_VALUE + MIN_VALUE) / 2;
    const static uint8_t telemetry = 0;

    uint16_t max, min = 0;
    if (bidirectional) {
        max = speed < 0 ? MID_VALUE : MAX_VALUE;
        min = speed < 0 ? MIN_VALUE : MID_VALUE;
    } else {
        max = MAX_VALUE;
        min = MIN_VALUE;
    }
    uint16_t adjusted_speed = (uint16_t) convert_range(abs(speed), max, min);
    uint16_t bit_frame = create_dshotFrame(adjusted_speed, telemetry);


    return write_frame_continuous(bit_frame);
}

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write_frame_continuous()

err_t Dshot::write_frame_continuous ( uint16_t  dshot_frame )

private

Write set Dshot frame continuously on the bus.

Parameters

dshot_frame

dhsot frame to send, already encoded in bits

Returns

• err_t::OK success
• err_t::FAIL on failure.

Definition at line 108 of file Dshot.cpp.

                                                        {
    err_t e;
    pthread_mutex_lock(&write_mut);
    e = _write_frame_continuous(dshot_frame);
    pthread_mutex_unlock(&write_mut);
    return e;
}

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Member Data Documentation

_continues_write

bool aruna::driver::Dshot::_continues_write = false

private

Definition at line 15 of file Dshot.h.

bidirectional

bool aruna::driver::Dshot::bidirectional

private

Definition at line 18 of file Dshot.h.

frequency

const uint32_t aruna::driver::Dshot::frequency

private

Definition at line 17 of file Dshot.h.

T0H_ns

uint16_t aruna::driver::Dshot::T0H_ns

protected

Definition at line 57 of file Dshot.h.

T0L_ns

uint16_t aruna::driver::Dshot::T0L_ns

protected

Definition at line 59 of file Dshot.h.

T1H_ns

uint16_t aruna::driver::Dshot::T1H_ns

protected

Definition at line 58 of file Dshot.h.

T1L_ns

uint16_t aruna::driver::Dshot::T1L_ns

protected

Definition at line 60 of file Dshot.h.

write_mut

pthread_mutex_t aruna::driver::Dshot::write_mut

private

Definition at line 16 of file Dshot.h.

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The documentation for this class was generated from the following files:

• include/aruna/driver/Dshot.h
• src/driver/Dshot.cpp