add support for the processing TMC26X tuning app

[clinton/Smoothieware.git] / src / modules / utils / motordrivercontrol / drivers / TMC26X / TMC26X.cpp

/*
 Highly modifed from....

 TMC26X.cpp - - TMC26X Stepper library for Wiring/Arduino

 based on the stepper library by Tom Igoe, et. al.

 Copyright (c) 2011, Interactive Matter, Marcus Nowotny

 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:

 The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.

 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.

 */

#include "TMC26X.h"
#include "mbed.h"
#include "StreamOutput.h"
#include "Kernel.h"
#include "libs/StreamOutputPool.h"


//! return value for TMC26X.getOverTemperature() if there is a overtemperature situation in the TMC chip
/*!
 * This warning indicates that the TCM chip is too warm.
 * It is still working but some parameters may be inferior.
 * You should do something against it.
 */
#define TMC26X_OVERTEMPERATURE_PREWARING 1
//! return value for TMC26X.getOverTemperature() if there is a overtemperature shutdown in the TMC chip
/*!
 * This warning indicates that the TCM chip is too warm to operate and has shut down to prevent damage.
 * It will stop working until it cools down again.
 * If you encouter this situation you must do something against it. Like reducing the current or improving the PCB layout
 * and/or heat management.
 */
#define TMC26X_OVERTEMPERATURE_SHUTDOWN 2

//which values can be read out
/*!
 * Selects to readout the microstep position from the motor.
 *\sa readStatus()
 */
#define TMC26X_READOUT_POSITION 0
/*!
 * Selects to read out the StallGuard value of the motor.
 *\sa readStatus()
 */
#define TMC26X_READOUT_STALLGUARD 1
/*!
 * Selects to read out the current current setting (acc. to CoolStep) and the upper bits of the StallGuard value from the motor.
 *\sa readStatus(), setCurrent()
 */
#define TMC26X_READOUT_CURRENT 3

/*!
 * Define to set the minimum current for CoolStep operation to 1/2 of the selected CS minium.
 *\sa setCoolStepConfiguration()
 */
#define COOL_STEP_HALF_CS_LIMIT 0
/*!
 * Define to set the minimum current for CoolStep operation to 1/4 of the selected CS minium.
 *\sa setCoolStepConfiguration()
 */
#define COOL_STEP_QUARTDER_CS_LIMIT 1


//some default values used in initialization
#define DEFAULT_MICROSTEPPING_VALUE 32

//TMC26X register definitions
#define DRIVER_CONTROL_REGISTER            0x00000ul
#define CHOPPER_CONFIG_REGISTER            0x80000ul
#define COOL_STEP_REGISTER                 0xA0000ul
#define STALL_GUARD2_LOAD_MEASURE_REGISTER 0xC0000ul
#define DRIVER_CONFIG_REGISTER             0xE0000ul

#define REGISTER_BIT_PATTERN               0xFFFFFul

//definitions for the driver control register DRVCTL
#define MICROSTEPPING_PATTERN          0x000Ful
#define STEP_INTERPOLATION             0x0200ul
#define DOUBLE_EDGE_STEP               0x0100ul

//definitions for the driver config register DRVCONF
#define READ_MICROSTEP_POSITION        0x0000ul
#define READ_STALL_GUARD_READING       0x0010ul
#define READ_STALL_GUARD_AND_COOL_STEP 0x0020ul
#define READ_SELECTION_PATTERN         0x0030ul
#define VSENSE                         0x0040ul

//definitions for the chopper config register
#define CHOPPER_MODE_STANDARD          0x00000ul
#define CHOPPER_MODE_T_OFF_FAST_DECAY  0x04000ul
#define T_OFF_PATTERN                  0x0000ful
#define RANDOM_TOFF_TIME               0x02000ul
#define BLANK_TIMING_PATTERN           0x18000ul
#define BLANK_TIMING_SHIFT             15
#define HYSTERESIS_DECREMENT_PATTERN   0x01800ul
#define HYSTERESIS_DECREMENT_SHIFT     11
#define HYSTERESIS_LOW_VALUE_PATTERN   0x00780ul
#define HYSTERESIS_LOW_SHIFT           7
#define HYSTERESIS_START_VALUE_PATTERN 0x00078ul
#define HYSTERESIS_START_VALUE_SHIFT   4
#define T_OFF_TIMING_PATERN            0x0000Ful

//definitions for cool step register
#define MINIMUM_CURRENT_FOURTH          0x8000ul
#define CURRENT_DOWN_STEP_SPEED_PATTERN 0x6000ul
#define SE_MAX_PATTERN                  0x0F00ul
#define SE_CURRENT_STEP_WIDTH_PATTERN   0x0060ul
#define SE_MIN_PATTERN                  0x000Ful

//definitions for stall guard2 current register
#define STALL_GUARD_FILTER_ENABLED          0x10000ul
#define STALL_GUARD_TRESHHOLD_VALUE_PATTERN 0x17F00ul
#define CURRENT_SCALING_PATTERN             0x0001Ful
#define STALL_GUARD_CONFIG_PATTERN          0x17F00ul
#define STALL_GUARD_VALUE_PATTERN           0x07F00ul

//definitions for the input from the TCM260
#define STATUS_STALL_GUARD_STATUS        0x00001ul
#define STATUS_OVER_TEMPERATURE_SHUTDOWN 0x00002ul
#define STATUS_OVER_TEMPERATURE_WARNING  0x00004ul
#define STATUS_SHORT_TO_GROUND_A         0x00008ul
#define STATUS_SHORT_TO_GROUND_B         0x00010ul
#define STATUS_OPEN_LOAD_A               0x00020ul
#define STATUS_OPEN_LOAD_B               0x00040ul
#define STATUS_STAND_STILL               0x00080ul
#define READOUT_VALUE_PATTERN            0xFFC00ul

//debuging output
//#define DEBUG

/*
 * Constructor
 */
TMC26X::TMC26X(std::function<int(uint8_t *b, int cnt, uint8_t *r)> spi) : spi(spi)
{
    //we are not started yet
    started = false;
    //by default cool step is not enabled
    cool_step_enabled = false;
}

void TMC26X::setResistor(unsigned int resistor)
{
    //store the current sense resistor value for later use
    this->resistor = resistor;
}

/*
 * configure the stepper driver
 * just must be called.
 */
void TMC26X::init()
{
    //setting the default register values
    driver_control_register_value = DRIVER_CONTROL_REGISTER;
    chopper_config_register = CHOPPER_CONFIG_REGISTER;
    cool_step_register_value = COOL_STEP_REGISTER;
    stall_guard2_current_register_value = STALL_GUARD2_LOAD_MEASURE_REGISTER;
    driver_configuration_register_value = DRIVER_CONFIG_REGISTER | READ_STALL_GUARD_READING;

    //set the initial values
    send262(driver_control_register_value);
    send262(chopper_config_register);
    send262(cool_step_register_value);
    send262(stall_guard2_current_register_value);
    send262(driver_configuration_register_value);

    started = true;

#if 0
    //set to a conservative start value
    setConstantOffTimeChopper(7, 54, 13, 12, 1);
#else
    // for 1.5amp kysan @ 12v
    setSpreadCycleChopper(5, 2, 5, 0, 0);
    // for 4amp Nema24 @ 12v
    //setSpreadCycleChopper(5, 2, 4, 0, 0);
#endif

    setEnabled(false);
    //set a nice microstepping value
    setMicrosteps(DEFAULT_MICROSTEPPING_VALUE);
}

void TMC26X::setCurrent(unsigned int current)
{
    uint8_t current_scaling = 0;
    //calculate the current scaling from the max current setting (in mA)
    double mASetting = (double)current;
    double resistor_value = (double) this->resistor;
    // remove vesense flag
    this->driver_configuration_register_value &= ~(VSENSE);
    //this is derrived from I=(cs+1)/32*(Vsense/Rsense)
    //leading to cs = CS = 32*R*I/V (with V = 0,31V oder 0,165V  and I = 1000*current)
    //with Rsense=0,15
    //for vsense = 0,310V (VSENSE not set)
    //or vsense = 0,165V (VSENSE set)
    current_scaling = (uint8_t)((resistor_value * mASetting * 32.0F / (0.31F * 1000.0F * 1000.0F)) - 0.5F); //theoretically - 1.0 for better rounding it is 0.5

    //check if the current scaling is too low
    if (current_scaling < 16) {
        //set the csense bit to get a use half the sense voltage (to support lower motor currents)
        this->driver_configuration_register_value |= VSENSE;
        //and recalculate the current setting
        current_scaling = (uint8_t)((resistor_value * mASetting * 32.0F / (0.165F * 1000.0F * 1000.0F)) - 0.5F); //theoretically - 1.0 for better rounding it is 0.5
    }

    //do some sanity checks
    if (current_scaling > 31) {
        current_scaling = 31;
    }
    //delete the old value
    stall_guard2_current_register_value &= ~(CURRENT_SCALING_PATTERN);
    //set the new current scaling
    stall_guard2_current_register_value |= current_scaling;
    //if started we directly send it to the motor
    if (started) {
        send262(driver_configuration_register_value);
        send262(stall_guard2_current_register_value);
    }
}

unsigned int TMC26X::getCurrent(void)
{
    //we calculate the current according to the datasheet to be on the safe side
    //this is not the fastest but the most accurate and illustrative way
    double result = (double)(stall_guard2_current_register_value & CURRENT_SCALING_PATTERN);
    double resistor_value = (double)this->resistor;
    double voltage = (driver_configuration_register_value & VSENSE) ? 0.165F : 0.31F;
    result = (result + 1.0F) / 32.0F * voltage / resistor_value * 1000.0F * 1000.0F;
    return (unsigned int)result;
}

void TMC26X::setStallGuardThreshold(int8_t stall_guard_threshold, int8_t stall_guard_filter_enabled)
{
    if (stall_guard_threshold < -64) {
        stall_guard_threshold = -64;
        //We just have 5 bits
    } else if (stall_guard_threshold > 63) {
        stall_guard_threshold = 63;
    }
    //add trim down to 7 bits
    stall_guard_threshold &= 0x7f;
    //delete old stall guard settings
    stall_guard2_current_register_value &= ~(STALL_GUARD_CONFIG_PATTERN);
    if (stall_guard_filter_enabled) {
        stall_guard2_current_register_value |= STALL_GUARD_FILTER_ENABLED;
    }
    //Set the new stall guard threshold
    stall_guard2_current_register_value |= (((unsigned long)stall_guard_threshold << 8) & STALL_GUARD_CONFIG_PATTERN);
    //if started we directly send it to the motor
    if (started) {
        send262(stall_guard2_current_register_value);
    }
}

int8_t TMC26X::getStallGuardThreshold(void)
{
    unsigned long stall_guard_threshold = stall_guard2_current_register_value & STALL_GUARD_VALUE_PATTERN;
    //shift it down to bit 0
    stall_guard_threshold >>= 8;
    //convert the value to an int to correctly handle the negative numbers
    int8_t result = stall_guard_threshold;
    //check if it is negative and fill it up with leading 1 for proper negative number representation
    if (result & (1 << 6)) {
        result |= 0xC0;
    }
    return result;
}

int8_t TMC26X::getStallGuardFilter(void)
{
    if (stall_guard2_current_register_value & STALL_GUARD_FILTER_ENABLED) {
        return -1;
    } else {
        return 0;
    }
}
/*
 * Set the number of microsteps per step.
 * 0,2,4,8,16,32,64,128,256 is supported
 * any value in between will be mapped to the next smaller value
 * 0 and 1 set the motor in full step mode
 */
void TMC26X::setMicrosteps(int number_of_steps)
{
    long setting_pattern;
    //poor mans log
    if (number_of_steps >= 256) {
        setting_pattern = 0;
        microsteps = 256;
    } else if (number_of_steps >= 128) {
        setting_pattern = 1;
        microsteps = 128;
    } else if (number_of_steps >= 64) {
        setting_pattern = 2;
        microsteps = 64;
    } else if (number_of_steps >= 32) {
        setting_pattern = 3;
        microsteps = 32;
    } else if (number_of_steps >= 16) {
        setting_pattern = 4;
        microsteps = 16;
    } else if (number_of_steps >= 8) {
        setting_pattern = 5;
        microsteps = 8;
    } else if (number_of_steps >= 4) {
        setting_pattern = 6;
        microsteps = 4;
    } else if (number_of_steps >= 2) {
        setting_pattern = 7;
        microsteps = 2;
        //1 and 0 lead to full step
    } else if (number_of_steps <= 1) {
        setting_pattern = 8;
        microsteps = 1;
    }

    //delete the old value
    this->driver_control_register_value &= 0xFFFF0ul;
    //set the new value
    this->driver_control_register_value |= setting_pattern;

    //if started we directly send it to the motor
    if (started) {
        send262(driver_control_register_value);
    }
}

/*
 * returns the effective number of microsteps at the moment
 */
int TMC26X::getMicrosteps(void)
{
    return microsteps;
}

void TMC26X::setStepInterpolation(int8_t value)
{
    if (value) {
        driver_control_register_value |= STEP_INTERPOLATION;
    } else {
        driver_control_register_value &= ~(STEP_INTERPOLATION);
    }
    //if started we directly send it to the motor
    if (started) {
        send262(driver_control_register_value);
    }
}

void TMC26X::setDoubleEdge(int8_t value)
{
    if (value) {
        driver_control_register_value |= DOUBLE_EDGE_STEP;
    } else {
        driver_control_register_value &= ~(DOUBLE_EDGE_STEP);
    }
    //if started we directly send it to the motor
    if (started) {
        send262(driver_control_register_value);
    }
}

/*
 * constant_off_time: The off time setting controls the minimum chopper frequency.
 * For most applications an off time within the range of 5μs to 20μs will fit.
 *      2...15: off time setting
 *
 * blank_time: Selects the comparator blank time. This time needs to safely cover the switching event and the
 * duration of the ringing on the sense resistor. For
 *      0: min. setting 3: max. setting
 *
 * fast_decay_time_setting: Fast decay time setting. With CHM=1, these bits control the portion of fast decay for each chopper cycle.
 *      0: slow decay only
 *      1...15: duration of fast decay phase
 *
 * sine_wave_offset: Sine wave offset. With CHM=1, these bits control the sine wave offset.
 * A positive offset corrects for zero crossing error.
 *      -3..-1: negative offset 0: no offset 1...12: positive offset
 *
 * use_current_comparator: Selects usage of the current comparator for termination of the fast decay cycle.
 * If current comparator is enabled, it terminates the fast decay cycle in case the current
 * reaches a higher negative value than the actual positive value.
 *      1: enable comparator termination of fast decay cycle
 *      0: end by time only
 */
void TMC26X::setConstantOffTimeChopper(int8_t constant_off_time, int8_t blank_time, int8_t fast_decay_time_setting, int8_t sine_wave_offset, uint8_t use_current_comparator)
{
    //perform some sanity checks
    if (constant_off_time < 2) {
        constant_off_time = 2;
    } else if (constant_off_time > 15) {
        constant_off_time = 15;
    }
    //save the constant off time
    this->constant_off_time = constant_off_time;
    int8_t blank_value;
    //calculate the value acc to the clock cycles
    if (blank_time >= 54) {
        blank_value = 3;
    } else if (blank_time >= 36) {
        blank_value = 2;
    } else if (blank_time >= 24) {
        blank_value = 1;
    } else {
        blank_value = 0;
    }
    if (fast_decay_time_setting < 0) {
        fast_decay_time_setting = 0;
    } else if (fast_decay_time_setting > 15) {
        fast_decay_time_setting = 15;
    }
    if (sine_wave_offset < -3) {
        sine_wave_offset = -3;
    } else if (sine_wave_offset > 12) {
        sine_wave_offset = 12;
    }
    //shift the sine_wave_offset
    sine_wave_offset += 3;

    //calculate the register setting
    //first of all delete all the values for this
    chopper_config_register &= ~((1 << 12) | BLANK_TIMING_PATTERN | HYSTERESIS_DECREMENT_PATTERN | HYSTERESIS_LOW_VALUE_PATTERN | HYSTERESIS_START_VALUE_PATTERN | T_OFF_TIMING_PATERN);
    //set the constant off pattern
    chopper_config_register |= CHOPPER_MODE_T_OFF_FAST_DECAY;
    //set the blank timing value
    chopper_config_register |= ((unsigned long)blank_value) << BLANK_TIMING_SHIFT;
    //setting the constant off time
    chopper_config_register |= constant_off_time;
    //set the fast decay time
    //set msb
    chopper_config_register |= (((unsigned long)(fast_decay_time_setting & 0x8)) << HYSTERESIS_DECREMENT_SHIFT);
    //other bits
    chopper_config_register |= (((unsigned long)(fast_decay_time_setting & 0x7)) << HYSTERESIS_START_VALUE_SHIFT);
    //set the sine wave offset
    chopper_config_register |= (unsigned long)sine_wave_offset << HYSTERESIS_LOW_SHIFT;
    //using the current comparator?
    if (!use_current_comparator) {
        chopper_config_register |= (1 << 12);
    }
    //if started we directly send it to the motor
    if (started) {
        send262(chopper_config_register);
    }
}

/*
 * constant_off_time: The off time setting controls the minimum chopper frequency.
 * For most applications an off time within the range of 5μs to 20μs will fit.
 *      2...15: off time setting
 *
 * blank_time: Selects the comparator blank time. This time needs to safely cover the switching event and the
 * duration of the ringing on the sense resistor. For
 *      0: min. setting 3: max. setting
 *
 * hysteresis_start: Hysteresis start setting. Please remark, that this value is an offset to the hysteresis end value HEND.
 *      1...8
 *
 * hysteresis_end: Hysteresis end setting. Sets the hysteresis end value after a number of decrements. Decrement interval time is controlled by HDEC.
 * The sum HSTRT+HEND must be <16. At a current setting CS of max. 30 (amplitude reduced to 240), the sum is not limited.
 *      -3..-1: negative HEND 0: zero HEND 1...12: positive HEND
 *
 * hysteresis_decrement: Hysteresis decrement setting. This setting determines the slope of the hysteresis during on time and during fast decay time.
 *      0: fast decrement 3: very slow decrement
 */

void TMC26X::setSpreadCycleChopper(int8_t constant_off_time, int8_t blank_time, int8_t hysteresis_start, int8_t hysteresis_end, int8_t hysteresis_decrement)
{
    //perform some sanity checks
    if (constant_off_time < 2) {
        constant_off_time = 2;
    } else if (constant_off_time > 15) {
        constant_off_time = 15;
    }
    //save the constant off time
    this->constant_off_time = constant_off_time;
    int8_t blank_value;
    //calculate the value acc to the clock cycles
    if (blank_time >= 54) {
        blank_value = 3;
    } else if (blank_time >= 36) {
        blank_value = 2;
    } else if (blank_time >= 24) {
        blank_value = 1;
    } else {
        blank_value = 0;
    }
    if (hysteresis_start < 1) {
        hysteresis_start = 1;
    } else if (hysteresis_start > 8) {
        hysteresis_start = 8;
    }
    hysteresis_start--;

    if (hysteresis_end < -3) {
        hysteresis_end = -3;
    } else if (hysteresis_end > 12) {
        hysteresis_end = 12;
    }
    //shift the hysteresis_end
    hysteresis_end += 3;

    if (hysteresis_decrement < 0) {
        hysteresis_decrement = 0;
    } else if (hysteresis_decrement > 3) {
        hysteresis_decrement = 3;
    }

    //first of all delete all the values for this
    chopper_config_register &= ~(CHOPPER_MODE_T_OFF_FAST_DECAY | BLANK_TIMING_PATTERN | HYSTERESIS_DECREMENT_PATTERN | HYSTERESIS_LOW_VALUE_PATTERN | HYSTERESIS_START_VALUE_PATTERN | T_OFF_TIMING_PATERN);

    //set the blank timing value
    chopper_config_register |= ((unsigned long)blank_value) << BLANK_TIMING_SHIFT;
    //setting the constant off time
    chopper_config_register |= constant_off_time;
    //set the hysteresis_start
    chopper_config_register |= ((unsigned long)hysteresis_start) << HYSTERESIS_START_VALUE_SHIFT;
    //set the hysteresis end
    chopper_config_register |= ((unsigned long)hysteresis_end) << HYSTERESIS_LOW_SHIFT;
    //set the hystereis decrement
    chopper_config_register |= ((unsigned long)hysteresis_decrement) << HYSTERESIS_DECREMENT_SHIFT;
    //if started we directly send it to the motor
    if (started) {
        send262(chopper_config_register);
    }
}

/*
 * In a constant off time chopper scheme both coil choppers run freely, i.e. are not synchronized.
 * The frequency of each chopper mainly depends on the coil current and the position dependant motor coil inductivity, thus it depends on the microstep position.
 * With some motors a slightly audible beat can occur between the chopper frequencies, especially when they are near to each other. This typically occurs at a
 * few microstep positions within each quarter wave. This effect normally is not audible when compared to mechanical noise generated by ball bearings, etc.
 * Further factors which can cause a similar effect are a poor layout of sense resistor GND connection.
 * Hint: A common factor, which can cause motor noise, is a bad PCB layout causing coupling of both sense resistor voltages
 * (please refer to sense resistor layout hint in chapter 8.1).
 * In order to minimize the effect of a beat between both chopper frequencies, an internal random generator is provided.
 * It modulates the slow decay time setting when switched on by the RNDTF bit. The RNDTF feature further spreads the chopper spectrum,
 * reducing electromagnetic emission on single frequencies.
 */
void TMC26X::setRandomOffTime(int8_t value)
{
    if (value) {
        chopper_config_register |= RANDOM_TOFF_TIME;
    } else {
        chopper_config_register &= ~(RANDOM_TOFF_TIME);
    }
    //if started we directly send it to the motor
    if (started) {
        send262(chopper_config_register);
    }
}

void TMC26X::setCoolStepConfiguration(unsigned int lower_SG_threshold, unsigned int SG_hysteresis, uint8_t current_decrement_step_size,
                                      uint8_t current_increment_step_size, uint8_t lower_current_limit)
{
    //sanitize the input values
    if (lower_SG_threshold > 480) {
        lower_SG_threshold = 480;
    }
    //divide by 32
    lower_SG_threshold >>= 5;
    if (SG_hysteresis > 480) {
        SG_hysteresis = 480;
    }
    //divide by 32
    SG_hysteresis >>= 5;
    if (current_decrement_step_size > 3) {
        current_decrement_step_size = 3;
    }
    if (current_increment_step_size > 3) {
        current_increment_step_size = 3;
    }
    if (lower_current_limit > 1) {
        lower_current_limit = 1;
    }
    //store the lower level in order to enable/disable the cool step
    this->cool_step_lower_threshold = lower_SG_threshold;
    //if cool step is not enabled we delete the lower value to keep it disabled
    if (!this->cool_step_enabled) {
        lower_SG_threshold = 0;
    }
    //the good news is that we can start with a complete new cool step register value
    //and simply set the values in the register
    cool_step_register_value = ((unsigned long)lower_SG_threshold) | (((unsigned long)SG_hysteresis) << 8) | (((unsigned long)current_decrement_step_size) << 5)
                               | (((unsigned long)current_increment_step_size) << 13) | (((unsigned long)lower_current_limit) << 15)
                               //and of course we have to include the signature of the register
                               | COOL_STEP_REGISTER;

    if (started) {
        send262(cool_step_register_value);
    }
}

void TMC26X::setCoolStepEnabled(bool enabled)
{
    //simply delete the lower limit to disable the cool step
    cool_step_register_value &= ~SE_MIN_PATTERN;
    //and set it to the proper value if cool step is to be enabled
    if (enabled) {
        cool_step_register_value |= this->cool_step_lower_threshold;
    }
    //and save the enabled status
    this->cool_step_enabled = enabled;
    //save the register value
    if (started) {
        send262(cool_step_register_value);
    }
}

bool TMC26X::isCoolStepEnabled(void)
{
    return this->cool_step_enabled;
}

unsigned int TMC26X::getCoolStepLowerSgThreshold()
{
    //we return our internally stored value - in order to provide the correct setting even if cool step is not enabled
    return this->cool_step_lower_threshold << 5;
}

unsigned int TMC26X::getCoolStepUpperSgThreshold()
{
    return (uint8_t)((cool_step_register_value & SE_MAX_PATTERN) >> 8) << 5;
}

uint8_t TMC26X::getCoolStepCurrentIncrementSize()
{
    return (uint8_t)((cool_step_register_value & CURRENT_DOWN_STEP_SPEED_PATTERN) >> 13);
}

uint8_t TMC26X::getCoolStepNumberOfSGReadings()
{
    return (uint8_t)((cool_step_register_value & SE_CURRENT_STEP_WIDTH_PATTERN) >> 5);
}

uint8_t TMC26X::getCoolStepLowerCurrentLimit()
{
    return (uint8_t)((cool_step_register_value & MINIMUM_CURRENT_FOURTH) >> 15);
}

void TMC26X::setEnabled(bool enabled)
{
    //delete the t_off in the chopper config to get sure
    chopper_config_register &= ~(T_OFF_PATTERN);
    if (enabled) {
        //and set the t_off time
        chopper_config_register |= this->constant_off_time;
    }
    //if not enabled we don't have to do anything since we already delete t_off from the register
    if (started) {
        send262(chopper_config_register);
    }
}

bool TMC26X::isEnabled()
{
    if (chopper_config_register & T_OFF_PATTERN) {
        return true;
    } else {
        return false;
    }
}

/*
 * reads a value from the TMC26X status register. The value is not obtained directly but can then
 * be read by the various status routines.
 *
 */
void TMC26X::readStatus(int8_t read_value)
{
    unsigned long old_driver_configuration_register_value = driver_configuration_register_value;
    //reset the readout configuration
    driver_configuration_register_value &= ~(READ_SELECTION_PATTERN);
    //this now equals TMC26X_READOUT_POSITION - so we just have to check the other two options
    if (read_value == TMC26X_READOUT_STALLGUARD) {
        driver_configuration_register_value |= READ_STALL_GUARD_READING;
    } else if (read_value == TMC26X_READOUT_CURRENT) {
        driver_configuration_register_value |= READ_STALL_GUARD_AND_COOL_STEP;
    }
    //all other cases are ignored to prevent funny values
    //check if the readout is configured for the value we are interested in
    if (driver_configuration_register_value != old_driver_configuration_register_value) {
        //because then we need to write the value twice - one time for configuring, second time to get the value, see below
        send262(driver_configuration_register_value);
    }
    //write the configuration to get the last status
    send262(driver_configuration_register_value);
}

//reads the stall guard setting from last status
//returns -1 if stallguard information is not present
int TMC26X::getCurrentStallGuardReading(void)
{
    //if we don't yet started there cannot be a stall guard value
    if (!started) {
        return -1;
    }
    //not time optimal, but solution optiomal:
    //first read out the stall guard value
    readStatus(TMC26X_READOUT_STALLGUARD);
    return getReadoutValue();
}

uint8_t TMC26X::getCurrentCSReading(void)
{
    //if we don't yet started there cannot be a stall guard value
    if (!started) {
        return 0;
    }

    //first read out the stall guard value
    readStatus(TMC26X_READOUT_CURRENT);
    return (getReadoutValue() & 0x1f);
}

unsigned int TMC26X::getCoolstepCurrent(void)
{
    float result = (float)getCurrentCSReading();
    float resistor_value = (float)this->resistor;
    float voltage = (driver_configuration_register_value & VSENSE) ? 0.165F : 0.31F;
    result = (result + 1.0F) / 32.0F * voltage / resistor_value * 1000.0F * 1000.0F;
    return (unsigned int)roundf(result);
}

/*
 return true if the stallguard threshold has been reached
*/
bool TMC26X::isStallGuardOverThreshold(void)
{
    if (!this->started) {
        return false;
    }
    return (driver_status_result & STATUS_STALL_GUARD_STATUS);
}

/*
 returns if there is any over temperature condition:
 OVER_TEMPERATURE_PREWARING if pre warning level has been reached
 OVER_TEMPERATURE_SHUTDOWN if the temperature is so hot that the driver is shut down
 Any of those levels are not too good.
*/
int8_t TMC26X::getOverTemperature(void)
{
    if (!this->started) {
        return 0;
    }
    if (driver_status_result & STATUS_OVER_TEMPERATURE_SHUTDOWN) {
        return TMC26X_OVERTEMPERATURE_SHUTDOWN;
    }
    if (driver_status_result & STATUS_OVER_TEMPERATURE_WARNING) {
        return TMC26X_OVERTEMPERATURE_PREWARING;
    }
    return 0;
}

//is motor channel A shorted to ground
bool TMC26X::isShortToGroundA(void)
{
    if (!this->started) {
        return false;
    }
    return (driver_status_result & STATUS_SHORT_TO_GROUND_A);
}

//is motor channel B shorted to ground
bool TMC26X::isShortToGroundB(void)
{
    if (!this->started) {
        return false;
    }
    return (driver_status_result & STATUS_SHORT_TO_GROUND_B);
}

//is motor channel A connected
bool TMC26X::isOpenLoadA(void)
{
    if (!this->started) {
        return false;
    }
    return (driver_status_result & STATUS_OPEN_LOAD_A);
}

//is motor channel B connected
bool TMC26X::isOpenLoadB(void)
{
    if (!this->started) {
        return false;
    }
    return (driver_status_result & STATUS_OPEN_LOAD_B);
}

//is chopper inactive since 2^20 clock cycles - defaults to ~0,08s
bool TMC26X::isStandStill(void)
{
    if (!this->started) {
        return false;
    }
    return (driver_status_result & STATUS_STAND_STILL);
}

//is chopper inactive since 2^20 clock cycles - defaults to ~0,08s
bool TMC26X::isStallGuardReached(void)
{
    if (!this->started) {
        return false;
    }
    return (driver_status_result & STATUS_STALL_GUARD_STATUS);
}

//reads the stall guard setting from last status
//returns -1 if stallguard inforamtion is not present
int TMC26X::getReadoutValue(void)
{
    return (int)(driver_status_result >> 10);
}

int TMC26X::getResistor()
{
    return this->resistor;
}

bool TMC26X::isCurrentScalingHalfed()
{
    if (this->driver_configuration_register_value & VSENSE) {
        return true;
    } else {
        return false;
    }
}

void TMC26X::dumpStatus(StreamOutput *stream)
{
    if (this->started) {
        readStatus(TMC26X_READOUT_POSITION); // get the status bits

        stream->printf("Chip type TMC26X\n");
        if (this->getOverTemperature()&TMC26X_OVERTEMPERATURE_PREWARING) {
            stream->printf("WARNING: Overtemperature Prewarning!\n");
        } else if (this->getOverTemperature()&TMC26X_OVERTEMPERATURE_SHUTDOWN) {
            stream->printf("ERROR: Overtemperature Shutdown!\n");
        }

        if (this->isShortToGroundA()) {
            stream->printf("ERROR: SHORT to ground on channel A!\n");
        }

        if (this->isShortToGroundB()) {
            stream->printf("ERROR: SHORT to ground on channel A!\n");
        }

        if (this->isOpenLoadA()) {
            stream->printf("ERROR: Channel A seems to be unconnected!\n");
        }

        if (this->isOpenLoadB()) {
            stream->printf("ERROR: Channel B seems to be unconnected!\n");
        }

        if (this->isStallGuardReached()) {
            stream->printf("INFO: Stall Guard level reached!\n");
        }

        if (this->isStandStill()) {
            stream->printf("INFO: Motor is standing still.\n");
        }

        int value = getReadoutValue();
        stream->printf("Microstep postion phase A: %d\n", value);

        value = getCurrentStallGuardReading();
        stream->printf("Stall Guard value: %d\n", value);

        stream->printf("Current setting: %dmA\n", getCurrent());
        stream->printf("Coolstep current: %dmA\n", getCoolstepCurrent());

        stream->printf("Microsteps: 1/%d\n", microsteps);

        stream->printf("Register dump:\n");
        stream->printf(" driver control register: %08lX(%ld)\n", driver_control_register_value, driver_control_register_value);
        stream->printf(" chopper config register: %08lX(%ld)\n", chopper_config_register, chopper_config_register);
        stream->printf(" cool step register: %08lX(%ld)\n", cool_step_register_value, cool_step_register_value);
        stream->printf(" stall guard2 current register: %08lX(%ld)\n", stall_guard2_current_register_value, stall_guard2_current_register_value);
        stream->printf(" driver configuration register: %08lX(%ld)\n", driver_configuration_register_value, driver_configuration_register_value);
        stream->printf(" motor_driver_control.xxx.reg %05lX,%05lX,%05lX,%05lX,%05lX\n", driver_control_register_value, chopper_config_register, cool_step_register_value, stall_guard2_current_register_value, driver_configuration_register_value);
    }
}

// sets a raw register to the value specified, for advanced settings
// register 0 writes them, 255 displays what registers are mapped to what
// FIXME status registers not reading back correctly, check docs
bool TMC26X::setRawRegister(StreamOutput *stream, uint32_t reg, uint32_t val)
{
    switch(reg) {
        case 255:
            send262(driver_control_register_value);
            send262(chopper_config_register);
            send262(cool_step_register_value);
            send262(stall_guard2_current_register_value);
            send262(driver_configuration_register_value);
            stream->printf("Registers written\n");
            break;


        case 1: driver_control_register_value = val; stream->printf("driver control register set to %lu\n", val); break;
        case 2: chopper_config_register = val; stream->printf("chopper config register set to %lu\n", val); break;
        case 3: cool_step_register_value = val; stream->printf("cool step register set to %lu\n", val); break;
        case 4: stall_guard2_current_register_value = val; stream->printf("stall guard2 current register set to %lu\n", val); break;
        case 5: driver_configuration_register_value = val; stream->printf("driver configuration register set to %lu\n", val); break;

        default:
            stream->printf("1: driver control register\n");
            stream->printf("2: chopper config register\n");
            stream->printf("3: cool step register\n");
            stream->printf("4: stall guard2 current register\n");
            stream->printf("5: driver configuration register\n");
            stream->printf("255: update all registers\n");
            return false;
    }
    return true;
}

/*
 * send register settings to the stepper driver via SPI
 * returns the current status
 * sends 20bits, the last 20 bits of the 24bits is taken as the command
 */
void TMC26X::send262(unsigned long datagram)
{
    uint8_t buf[] {(uint8_t)(datagram >> 16), (uint8_t)(datagram >>  8), (uint8_t)(datagram & 0xff)};
    uint8_t rbuf[3];

    //write/read the values
    spi(buf, 3, rbuf);

    // construct reply
    unsigned long i_datagram = ((rbuf[0] << 16) | (rbuf[1] << 8) | (rbuf[2])) >> 4;

    //store the datagram as status result
    driver_status_result = i_datagram;

    //THEKERNEL->streams->printf("sent: %02X, %02X, %02X received: %02X, %02X, %02X \n", buf[0], buf[1], buf[2], rbuf[0], rbuf[1], rbuf[2]);
}

#define HAS(X) (options.find(X) != options.end())
#define GET(X) (options.at(X))
bool TMC26X::set_options(const options_t& options)
{
    bool set= false;
    if(HAS('O') || HAS('Q')) {
        // void TMC26X::setStallGuardThreshold(int8_t stall_guard_threshold, int8_t stall_guard_filter_enabled)
        int8_t o= HAS('O') ? GET('O') : getStallGuardThreshold();
        int8_t q= HAS('Q') ? GET('Q') : getStallGuardFilter();
        setStallGuardThreshold(o, q);
        set= true;
    }

    if(HAS('H') && HAS('I') && HAS('J') && HAS('K') && HAS('L')) {
        //void TMC26X::setCoolStepConfiguration(unsigned int lower_SG_threshold, unsigned int SG_hysteresis, uint8_t current_decrement_step_size, uint8_t current_increment_step_size, uint8_t lower_current_limit)
        setCoolStepConfiguration(GET('H'), GET('I'), GET('J'), GET('K'), GET('L'));
        set= true;
    }

    if(HAS('S')) {
        uint32_t s= GET('S');
        if(s==0 && HAS('U') && HAS('V') && HAS('W') && HAS('X') && HAS('Y')) {
            //void TMC26X::setConstantOffTimeChopper(int8_t constant_off_time, int8_t blank_time, int8_t fast_decay_time_setting, int8_t sine_wave_offset, uint8_t use_current_comparator)
            setConstantOffTimeChopper(GET('U'), GET('V'), GET('W'), GET('X'), GET('Y'));
            set= true;

        }else if(s==1 && HAS('U') && HAS('V') && HAS('W') && HAS('X') && HAS('Y')) {
            //void TMC26X::setSpreadCycleChopper(int8_t constant_off_time, int8_t blank_time, int8_t hysteresis_start, int8_t hysteresis_end, int8_t hysteresis_decrement);
            setSpreadCycleChopper(GET('U'), GET('V'), GET('W'), GET('X'), GET('Y'));
            set= true;

        }else if(s==2 && HAS('Z')) {
            setRandomOffTime(GET('Z'));
            set= true;

        }else if(s==3 && HAS('Z')) {
            setDoubleEdge(GET('Z'));
            set= true;

        }else if(s==4 && HAS('Z')) {
            setStepInterpolation(GET('Z'));
            set= true;

        }else if(s==5 && HAS('Z')) {
            setCoolStepEnabled(GET('Z') == 1);
            set= true;
        }
    }

    return set;
}