File content as of revision 1:9efe863db15e:

/******************************************************//**
 * @file    easyspin.cpp
 * @version V1.0
 * @date    June 29, 2015
 * @brief   easyspin library for mbed
 *
 * This file is free software; you can redistribute it and/or modify
 * it under the terms of either the GNU General Public License version 2
 * or the GNU Lesser General Public License version 2.1, both as
 * published by the Free Software Foundation.
 **********************************************************/

#include "easyspin.h"
#include "mbed.h"

const uint16_t Easyspin::prescalerArrayTimer0_1[PRESCALER_ARRAY_TIMER0_1_SIZE] = { 0, 1, 8, 64, 256, 1024};
const uint16_t Easyspin::prescalerArrayTimer2[PRESCALER_ARRAY_TIMER2_SIZE] = {0, 1, 8, 32, 64, 128, 256, 1024};
volatile void (*Easyspin::flagInterruptCallback)(void);
volatile uint8_t Easyspin::numberOfShields;
uint8_t Easyspin::spiTxBursts[Easyspin_CMD_ARG_MAX_NB_BYTES][MAX_NUMBER_OF_SHIELDS];
uint8_t Easyspin::spiRxBursts[Easyspin_CMD_ARG_MAX_NB_BYTES][MAX_NUMBER_OF_SHIELDS];
volatile bool Easyspin::spiPreemtionByIsr = false;
volatile bool Easyspin::isrFlag = false;
volatile class Easyspin* Easyspin::instancePtr = NULL;

/******************************************************//**
 * @brief  Constructor
 * @param  None
 * @retval None
 **********************************************************/
Easyspin::Easyspin():reset(Easyspin_Reset_Pin), dir1(Easyspin_DIR_1_Pin), dir2(Easyspin_DIR_2_Pin),
    dir3(Easyspin_DIR_3_Pin), CS(Easyspin_CS_Pin), flag(Easyspin_FLAG_Pin), pwm1(Easyspin_PWM_1_Pin),
    pwm2(Easyspin_PWM_2_Pin), pwm3(Easyspin_PWM_3_Pin), spi(Easyspin_MOSI_Pin, Easyspin_MISO_Pin, Easyspin_SCK_Pin)
{
    uint8_t i;
    for (i = 0; i < MAX_NUMBER_OF_SHIELDS; i++) {
        shieldPrm[i].motionState = INACTIVE;
        shieldPrm[i].commandExecuted = NO_CMD;
        shieldPrm[i].stepsToTake = MAX_STEPS;
    }
    instancePtr = this;
}

/******************************************************//**
 * @brief  Attaches a user callback to the flag Interrupt
 * The call back will be then called each time the status
 * flag pin will be pulled down due to the occurrence of
 * a programmed alarms ( OCD, thermal pre-warning or
 * shutdown, UVLO, wrong command, non-performable command)
 * @param[in] callback Name of the callback to attach
 * to the Flag Interrupt
 * @retval None
 **********************************************************/
void Easyspin::AttachFlagInterrupt(void (*callback)(void))
{
    flagInterruptCallback = (volatile void (*)())callback;
}

/******************************************************//**
 * @brief Starts the Easyspin library
 * @param[in] nbShields Number of Easyspin shields to use (from 1 to 3)
 * @retval None
 **********************************************************/
void Easyspin::Begin(uint8_t nbShields)
{
    numberOfShields = nbShields;

    // start the SPI library:
    //SPI.begin();
    //SPI.setBitOrder(MSBFIRST);
    spi.format(8, 3);
    //SPI.setClockDivider(SPI_CLOCK_DIV4);

    // flag pin
    //pinMode(Easyspin_FLAG_Pin, INPUT_PULLUP);
    flag.mode(PullUp);
    flag.fall(&FlagInterruptHandler);

    //reset pin
    //pinMode(Easyspin_Reset_Pin, OUTPUT);

    switch (nbShields) {
        case 3:
            //pinMode(Easyspin_DIR_3_Pin, OUTPUT);
            //pinMode(Easyspin_PWM_3_Pin, OUTPUT);
            PwmInit(2);
        case 2:
            //pinMode(Easyspin_DIR_2_Pin, OUTPUT);
            //pinMode(Easyspin_PWM_2_Pin, OUTPUT);
            PwmInit(1);
        case 1:
            //pinMode(Easyspin_DIR_1_Pin, OUTPUT);
            //pinMode(Easyspin_PWM_1_Pin, OUTPUT);
            PwmInit(0);
        default:
            ;
    }

    /* Standby-reset deactivation */
    ReleaseReset();

    /* Set all registers and context variables to the predefined values from Easyspin_target_config.h */
    SetShieldParamsToPredefinedValues();

    /* Disable Easyspin powerstage */
    for (uint32_t i = 0; i < nbShields; i++) {
        CmdDisable(i);
        /* Get Status to clear flags after start up */
        CmdGetStatus(i);
    }
}

/******************************************************//**
 * @brief Returns the acceleration of the specified shield
 * @param[in] shieldId (from 0 to 2)
 * @retval Acceleration in pps^2
 **********************************************************/
uint16_t Easyspin::GetAcceleration(uint8_t shieldId)
{
    return (shieldPrm[shieldId].acceleration);
}

/******************************************************//**
 * @brief Returns the current speed of the specified shield
 * @param[in] shieldId (from 0 to 2)
 * @retval Speed in pps
 **********************************************************/
uint16_t Easyspin::GetCurrentSpeed(uint8_t shieldId)
{
    return shieldPrm[shieldId].speed;
}

/******************************************************//**
 * @brief Returns the deceleration of the specified shield
 * @param[in] shieldId (from 0 to 2)
 * @retval Deceleration in pps^2
 **********************************************************/
uint16_t Easyspin::GetDeceleration(uint8_t shieldId)
{
    return (shieldPrm[shieldId].deceleration);
}

/******************************************************//**
 * @brief Returns the FW version of the library
 * @param None
 * @retval Easyspin_FW_VERSION
 **********************************************************/
uint8_t Easyspin::GetFwVersion(void)
{
    return (Easyspin_FW_VERSION);
}

/******************************************************//**
 * @brief  Returns the mark position  of the specified shield
 * @param[in] shieldId (from 0 to 2)
 * @retval Mark register value converted in a 32b signed integer
 **********************************************************/
int32_t Easyspin::GetMark(uint8_t shieldId)
{
    return ConvertPosition(CmdGetParam(shieldId,Easyspin_MARK));
}

/******************************************************//**
 * @brief  Returns the max speed of the specified shield
 * @param[in] shieldId (from 0 to 2)
 * @retval maxSpeed in pps
 **********************************************************/
uint16_t Easyspin::GetMaxSpeed(uint8_t shieldId)
{
    return (shieldPrm[shieldId].maxSpeed);
}

/******************************************************//**
 * @brief  Returns the min speed of the specified shield
 * @param[in] shieldId (from 0 to 2)
 * @retval minSpeed in pps
 **********************************************************/
uint16_t Easyspin::GetMinSpeed(uint8_t shieldId)
{
    return (shieldPrm[shieldId].minSpeed);
}

/******************************************************//**
 * @brief  Returns the ABS_POSITION of the specified shield
 * @param[in] shieldId (from 0 to 2)
 * @retval ABS_POSITION register value converted in a 32b signed integer
 **********************************************************/
int32_t Easyspin::GetPosition(uint8_t shieldId)
{
    return ConvertPosition(CmdGetParam(shieldId,Easyspin_ABS_POS));
}

/******************************************************//**
 * @brief Returns the shield state
 * @param[in] shieldId (from 0 to 2)
 * @retval State (ACCELERATING, DECELERATING, STEADY or INACTIVE)
 **********************************************************/
shieldState_t Easyspin::GetShieldState(uint8_t shieldId)
{
    return shieldPrm[shieldId].motionState;
}

/******************************************************//**
 * @brief  Requests the motor to move to the home position (ABS_POSITION = 0)
 * @param[in] shieldId (from 0 to 2)
 * @retval None
 **********************************************************/
void Easyspin::GoHome(uint8_t shieldId)
{
    GoTo(shieldId, 0);
}

/******************************************************//**
 * @brief  Requests the motor to move to the mark position
 * @param[in] shieldId (from 0 to 2)
 * @retval None
 **********************************************************/
void Easyspin::GoMark(uint8_t shieldId)
{
    uint32_t mark;

    mark = ConvertPosition(CmdGetParam(shieldId,Easyspin_MARK));
    GoTo(shieldId,mark);
}

/******************************************************//**
 * @brief  Requests the motor to move to the specified position
 * @param[in] shieldId (from 0 to 2)
 * @param[in] targetPosition absolute position in steps
 * @retval None
 **********************************************************/
void Easyspin::GoTo(uint8_t shieldId, int32_t targetPosition)
{
    dir_t direction;
    int32_t steps;

    /* Eventually deactivate motor */
    if (shieldPrm[shieldId].motionState != INACTIVE) {
        HardStop(shieldId);
    }

    /* Get current position */
    shieldPrm[shieldId].currentPosition = ConvertPosition(CmdGetParam(shieldId,Easyspin_ABS_POS));

    /* Compute the number of steps to perform */
    steps = targetPosition - shieldPrm[shieldId].currentPosition;

    if (steps >= 0) {
        shieldPrm[shieldId].stepsToTake = steps;
        direction = FORWARD;

    } else {
        shieldPrm[shieldId].stepsToTake = -steps;
        direction = BACKWARD;
    }

    if (steps != 0) {

        shieldPrm[shieldId].commandExecuted = MOVE_CMD;

        /* Direction setup */
        SetDirection(shieldId,direction);

        ComputeSpeedProfile(shieldId, shieldPrm[shieldId].stepsToTake);

        /* Motor activation */
        StartMovement(shieldId);
    }
}

/******************************************************//**
 * @brief  Immediatly stops the motor and disable the power bridge
 * @param[in] shieldId (from 0 to 2)
 * @retval None
 **********************************************************/
void Easyspin::HardStop(uint8_t shieldId)
{
    /* Disable corresponding PWM */
    PwmStop(shieldId);

    /* Disable power stage */
    CmdDisable(shieldId);

    /* Set inactive state */
    shieldPrm[shieldId].motionState = INACTIVE;
    shieldPrm[shieldId].commandExecuted = NO_CMD;
    shieldPrm[shieldId].stepsToTake = MAX_STEPS;

#ifdef _DEBUG_Easyspin
    Serial.println("Inactive\n");
#endif
}

/******************************************************//**
 * @brief  Moves the motor of the specified number of steps
 * @param[in] shieldId (from 0 to 2)
 * @param[in] direction FORWARD or BACKWARD
 * @param[in] stepCount Number of steps to perform
 * @retval None
 **********************************************************/
void Easyspin::Move(uint8_t shieldId, dir_t direction, uint32_t stepCount)
{
    /* Eventually deactivate motor */
    if (shieldPrm[shieldId].motionState != INACTIVE) {
        HardStop(shieldId);
    }

    if (stepCount != 0) {
        shieldPrm[shieldId].stepsToTake = stepCount;

        shieldPrm[shieldId].commandExecuted = MOVE_CMD;

        shieldPrm[shieldId].currentPosition = ConvertPosition(CmdGetParam(shieldId,Easyspin_ABS_POS));

        /* Direction setup */
        SetDirection(shieldId,direction);

        ComputeSpeedProfile(shieldId, stepCount);

        /* Motor activation */
        StartMovement(shieldId);
    }
}


/******************************************************//**
 * @brief  Turn left or right with the specified angle
 * @param[in] rotation RIGHT or LEFT
 * @param[in] angle in degrees
 * @retval None
 **********************************************************/
void Easyspin::Turn(rot_t rotation, uint16_t angle)
{
    uint16_t nbStep = (10934*angle)/360;
    if(rotation==RIGHT) {
        Move(0, FORWARD, nbStep);
        Move(1, FORWARD, nbStep);
    } else {
        Move(0, BACKWARD, nbStep);
        Move(1, BACKWARD, nbStep);
    }
}

/******************************************************//**
 * @brief  Move forward or backward with the specified distance
 * @param[in] direction FORWARD or BACKWARD
 * @param[in] distance in cm
 * @retval None
 **********************************************************/
void Easyspin::Move_cm(dir_t direction, uint16_t distance)
{
    uint16_t nbStep = (10000 * distance)/61;
    if(direction==FORWARD) {
        Move(0, FORWARD, nbStep);
        Move(1, BACKWARD, nbStep);
    } else {
        Move(0, BACKWARD, nbStep);
        Move(1, FORWARD, nbStep);
    }
}

/******************************************************//**
 * @brief Resets all Easyspin shields
 * @param None
 * @retval None
 **********************************************************/
void Easyspin::ResetAllShields(void)
{
    uint8_t loop;

    for (loop = 0; loop < numberOfShields; loop++) {
        /* Stop movement and disable power stage*/
        HardStop(loop);
    }
    Reset();
    wait_us(20); // Reset pin must be forced low for at least 10us
    ReleaseReset();
}

/******************************************************//**
 * @brief  Runs the motor. It will accelerate from the min
 * speed up to the max speed by using the shield acceleration.
 * @param[in] shieldId (from 0 to 2)
 * @param[in] direction FORWARD or BACKWARD
 * @retval None
 **********************************************************/
void Easyspin::Run(uint8_t shieldId, dir_t direction)
{
    /* Eventually deactivate motor */
    if (shieldPrm[shieldId].motionState != INACTIVE) {
        HardStop(shieldId);
    }

    /* Direction setup */
    SetDirection(shieldId,direction);

    shieldPrm[shieldId].commandExecuted = RUN_CMD;

    /* Motor activation */
    StartMovement(shieldId);
}

/******************************************************//**
 * @brief  Changes the acceleration of the specified shield
 * @param[in] shieldId (from 0 to 2)
 * @param[in] newAcc New acceleration to apply in pps^2
 * @retval true if the command is successfully executed, else false
 * @note The command is not performed is the shield is executing
 * a MOVE or GOTO command (but it can be used during a RUN command)
 **********************************************************/
bool Easyspin::SetAcceleration(uint8_t shieldId,uint16_t newAcc)
{
    bool cmdExecuted = false;
    if ((newAcc != 0)&&
            ((shieldPrm[shieldId].motionState == INACTIVE)||
             (shieldPrm[shieldId].commandExecuted == RUN_CMD))) {
        shieldPrm[shieldId].acceleration = newAcc;
        cmdExecuted = true;
    }
    return cmdExecuted;
}

/******************************************************//**
 * @brief  Changes the deceleration of the specified shield
 * @param[in] shieldId (from 0 to 2)
 * @param[in] newDec New deceleration to apply in pps^2
 * @retval true if the command is successfully executed, else false
 * @note The command is not performed is the shield is executing
 * a MOVE or GOTO command (but it can be used during a RUN command)
 **********************************************************/
bool Easyspin::SetDeceleration(uint8_t shieldId, uint16_t newDec)
{
    bool cmdExecuted = false;
    if ((newDec != 0)&&
            ((shieldPrm[shieldId].motionState == INACTIVE)||
             (shieldPrm[shieldId].commandExecuted == RUN_CMD))) {
        shieldPrm[shieldId].deceleration = newDec;
        cmdExecuted = true;
    }
    return cmdExecuted;
}

/******************************************************//**
 * @brief  Set current position to be the Home position (ABS pos set to 0)
 * @param[in] shieldId (from 0 to 2)
 * @retval None
 **********************************************************/
void Easyspin::SetHome(uint8_t shieldId)
{
    CmdSetParam(shieldId, Easyspin_ABS_POS, 0);
}

/******************************************************//**
 * @brief  Sets current position to be the Mark position
 * @param[in] shieldId (from 0 to 2)
 * @retval None
 **********************************************************/
void Easyspin::SetMark(uint8_t shieldId)
{
    uint32_t mark = CmdGetParam(shieldId,Easyspin_ABS_POS);
    CmdSetParam(shieldId,Easyspin_MARK, mark);
}

/******************************************************//**
 * @brief  Changes the max speed of the specified shield
 * @param[in] shieldId (from 0 to 2)
 * @param[in] newMaxSpeed New max speed  to apply in pps
 * @retval true if the command is successfully executed, else false
 * @note The command is not performed is the shield is executing
 * a MOVE or GOTO command (but it can be used during a RUN command).
 **********************************************************/
bool Easyspin::SetMaxSpeed(uint8_t shieldId, uint16_t newMaxSpeed)
{
    bool cmdExecuted = false;
    if ((newMaxSpeed > Easyspin_MIN_PWM_FREQ)&&
            (newMaxSpeed <= Easyspin_MAX_PWM_FREQ) &&
            (shieldPrm[shieldId].minSpeed <= newMaxSpeed) &&
            ((shieldPrm[shieldId].motionState == INACTIVE)||
             (shieldPrm[shieldId].commandExecuted == RUN_CMD))) {
        shieldPrm[shieldId].maxSpeed = newMaxSpeed;
        cmdExecuted = true;
    }
    return cmdExecuted;
}

/******************************************************//**
 * @brief  Changes the min speed of the specified shield
 * @param[in] shieldId (from 0 to 2)
 * @param[in] newMinSpeed New min speed  to apply in pps
 * @retval true if the command is successfully executed, else false
 * @note The command is not performed is the shield is executing
 * a MOVE or GOTO command (but it can be used during a RUN command).
 **********************************************************/
bool Easyspin::SetMinSpeed(uint8_t shieldId, uint16_t newMinSpeed)
{
    bool cmdExecuted = false;
    if ((newMinSpeed >= Easyspin_MIN_PWM_FREQ)&&
            (newMinSpeed < Easyspin_MAX_PWM_FREQ) &&
            (newMinSpeed <= shieldPrm[shieldId].maxSpeed) &&
            ((shieldPrm[shieldId].motionState == INACTIVE)||
             (shieldPrm[shieldId].commandExecuted == RUN_CMD))) {
        shieldPrm[shieldId].minSpeed = newMinSpeed;
        cmdExecuted = true;
    }
    return cmdExecuted;
}

/******************************************************//**
 * @brief  Stops the motor by using the shield deceleration
 * @param[in] shieldId (from 0 to 2)
 * @retval true if the command is successfully executed, else false
 * @note The command is not performed is the shield is in INACTIVE state.
 **********************************************************/
bool Easyspin::SoftStop(uint8_t shieldId)
{
    bool cmdExecuted = false;
    if (shieldPrm[shieldId].motionState != INACTIVE) {
        shieldPrm[shieldId].commandExecuted = SOFT_STOP_CMD;
        cmdExecuted = true;
    }
    return (cmdExecuted);
}

/******************************************************//**
 * @brief  Locks until the shield state becomes Inactive
 * @param[in] shieldId (from 0 to 2)
 * @retval None
 **********************************************************/
void Easyspin::WaitWhileActive(uint8_t shieldId)
{
    /* Wait while motor is running */
    while (GetShieldState(shieldId) != INACTIVE);
}

/******************************************************//**
 * @brief  Issue the Disable command to the Easyspin of the specified shield
 * @param[in] shieldId (from 0 to 2)
 * @retval None
 **********************************************************/
void Easyspin::CmdDisable(uint8_t shieldId)
{
    SendCommand(shieldId, Easyspin_DISABLE);
}

/******************************************************//**
 * @brief  Issues the Enable command to the Easyspin of the specified shield
 * @param[in] shieldId (from 0 to 2)
 * @retval None
 **********************************************************/
void Easyspin::CmdEnable(uint8_t shieldId)
{
    SendCommand(shieldId, Easyspin_ENABLE);
}

/******************************************************//**
 * @brief  Issues the GetParam command to the Easyspin of the specified shield
 * @param[in] shieldId (from 0 to 2)
 * @param[in] param Register adress (Easyspin_ABS_POS, Easyspin_MARK,...)
 * @retval Register value
 **********************************************************/
uint32_t Easyspin::CmdGetParam(uint8_t shieldId, Easyspin_Registers_t param)
{
    uint32_t i;
    uint32_t spiRxData;
    uint8_t maxArgumentNbBytes = 0;
    uint8_t spiIndex = numberOfShields - shieldId - 1;
    bool itDisable = false;

    do {
        spiPreemtionByIsr = false;
        if (itDisable) {
            /* re-enable interrupts if disable in previous iteration */
            flag.enable_irq();
            itDisable = false;
        }

        for (i = 0; i < numberOfShields; i++) {
            spiTxBursts[0][i] = Easyspin_NOP;
            spiTxBursts[1][i] = Easyspin_NOP;
            spiTxBursts[2][i] = Easyspin_NOP;
            spiTxBursts[3][i] = Easyspin_NOP;
            spiRxBursts[1][i] = 0;
            spiRxBursts[2][i] = 0;
            spiRxBursts[3][i] = 0;
        }
        switch (param) {
            case Easyspin_ABS_POS:
                ;
            case Easyspin_MARK:
                spiTxBursts[0][spiIndex] = ((uint8_t)Easyspin_GET_PARAM )| (param);
                maxArgumentNbBytes = 3;
                break;
            case Easyspin_EL_POS:
                ;
            case Easyspin_CONFIG:
                ;
            case Easyspin_STATUS:
                spiTxBursts[1][spiIndex] = ((uint8_t)Easyspin_GET_PARAM )| (param);
                maxArgumentNbBytes = 2;
                break;
            default:
                spiTxBursts[2][spiIndex] = ((uint8_t)Easyspin_GET_PARAM )| (param);
                maxArgumentNbBytes = 1;
        }

        /* Disable interruption before checking */
        /* pre-emption by ISR and SPI transfers*/
        flag.disable_irq();
        itDisable = true;
    } while (spiPreemtionByIsr); // check pre-emption by ISR

    for (i = Easyspin_CMD_ARG_MAX_NB_BYTES-1-maxArgumentNbBytes;
            i < Easyspin_CMD_ARG_MAX_NB_BYTES;
            i++) {
        WriteBytes(&spiTxBursts[i][0],
                   &spiRxBursts[i][0]);
    }

    spiRxData = ((uint32_t)spiRxBursts[1][spiIndex] << 16)|
                (spiRxBursts[2][spiIndex] << 8) |
                (spiRxBursts[3][spiIndex]);

    /* re-enable interrupts after SPI transfers*/
    flag.enable_irq();

    return (spiRxData);
}

/******************************************************//**
 * @brief  Issues the GetStatus command to the Easyspin of the specified shield
 * @param[in] shieldId (from 0 to 2)
 * @retval Status Register value
 * @note Once the GetStatus command is performed, the flags of the status register
 * are reset. This is not the case when the status register is read with the
 * GetParam command (via the functions ReadStatusRegister or CmdGetParam).
 **********************************************************/
uint16_t Easyspin::CmdGetStatus(uint8_t shieldId)
{
    uint32_t i;
    uint16_t status;
    uint8_t spiIndex = numberOfShields - shieldId - 1;
    bool itDisable = false;

    do {
        spiPreemtionByIsr = false;
        if (itDisable) {
            /* re-enable interrupts if disable in previous iteration */
            flag.enable_irq();
            itDisable = false;
        }

        for (i = 0; i < numberOfShields; i++) {
            spiTxBursts[0][i] = Easyspin_NOP;
            spiTxBursts[1][i] = Easyspin_NOP;
            spiTxBursts[2][i] = Easyspin_NOP;
            spiRxBursts[1][i] = 0;
            spiRxBursts[2][i] = 0;
        }
        spiTxBursts[0][spiIndex] = Easyspin_GET_STATUS;

        /* Disable interruption before checking */
        /* pre-emption by ISR and SPI transfers*/
        flag.disable_irq();
        itDisable = true;
    } while (spiPreemtionByIsr); // check pre-emption by ISR

    for (i = 0; i < Easyspin_CMD_ARG_NB_BYTES_GET_STATUS + Easyspin_RSP_NB_BYTES_GET_STATUS; i++) {
        WriteBytes(&spiTxBursts[i][0], &spiRxBursts[i][0]);
    }
    status = (spiRxBursts[1][spiIndex] << 8) | (spiRxBursts[2][spiIndex]);

    /* re-enable interrupts after SPI transfers*/
    flag.enable_irq();

    return (status);
}

/******************************************************//**
 * @brief  Issues the Nop command to the Easyspin of the specified shield
 * @param[in] shieldId (from 0 to 2)
 * @retval None
 **********************************************************/
void Easyspin::CmdNop(uint8_t shieldId)
{
    SendCommand(shieldId, Easyspin_NOP);
}

/******************************************************//**
 * @brief  Issues the SetParam command to the Easyspin of the specified shield
 * @param[in] shieldId (from 0 to 2)
 * @param[in] param Register adress (Easyspin_ABS_POS, Easyspin_MARK,...)
 * @param[in] value Value to set in the register
 * @retval None
 **********************************************************/
void Easyspin::CmdSetParam(uint8_t shieldId,
                           Easyspin_Registers_t param,
                           uint32_t value)
{
    uint32_t i;
    uint8_t maxArgumentNbBytes = 0;
    uint8_t spiIndex = numberOfShields - shieldId - 1;
    bool itDisable = false;
    do {
        spiPreemtionByIsr = false;
        if (itDisable) {
            /* re-enable interrupts if disable in previous iteration */
            flag.enable_irq();//interrupts();
            itDisable = false;
        }
        for (i = 0; i < numberOfShields; i++) {
            spiTxBursts[0][i] = Easyspin_NOP;
            spiTxBursts[1][i] = Easyspin_NOP;
            spiTxBursts[2][i] = Easyspin_NOP;
            spiTxBursts[3][i] = Easyspin_NOP;
        }
        switch (param) {
            case Easyspin_ABS_POS:
                ;
            case Easyspin_MARK:
                spiTxBursts[0][spiIndex] = param;
                spiTxBursts[1][spiIndex] = (uint8_t)(value >> 16);
                spiTxBursts[2][spiIndex] = (uint8_t)(value >> 8);
                maxArgumentNbBytes = 3;
                break;
            case Easyspin_EL_POS:
                ;
            case Easyspin_CONFIG:
                spiTxBursts[1][spiIndex] = param;
                spiTxBursts[2][spiIndex] = (uint8_t)(value >> 8);
                maxArgumentNbBytes = 2;
                break;
            default:
                spiTxBursts[2][spiIndex] = param;
                maxArgumentNbBytes = 1;
        }
        spiTxBursts[3][spiIndex] = (uint8_t)(value);

        /* Disable interruption before checking */
        /* pre-emption by ISR and SPI transfers*/
        flag.disable_irq();
        itDisable = true;
    } while (spiPreemtionByIsr); // check pre-emption by ISR

    /* SPI transfer */
    for (i = Easyspin_CMD_ARG_MAX_NB_BYTES-1-maxArgumentNbBytes;
            i < Easyspin_CMD_ARG_MAX_NB_BYTES;
            i++) {
        WriteBytes(&spiTxBursts[i][0],&spiRxBursts[i][0]);
    }
    /* re-enable interrupts after SPI transfers*/
    flag.enable_irq();
}

/******************************************************//**
 * @brief  Reads the Status Register value
 * @param[in] shieldId (from 0 to 2)
 * @retval Status register valued
 * @note The status register flags are not cleared
 * at the difference with CmdGetStatus()
 **********************************************************/
uint16_t Easyspin::ReadStatusRegister(uint8_t shieldId)
{
    return (CmdGetParam(shieldId,Easyspin_STATUS));
}

/******************************************************//**
 * @brief  Releases the Easyspin reset (pin set to High) of all shields
 * @param  None
 * @retval None
 **********************************************************/
void Easyspin::ReleaseReset(void)
{
    reset = 1;
}

/******************************************************//**
 * @brief  Resets the Easyspin (reset pin set to low) of all shields
 * @param  None
 * @retval None
 **********************************************************/
void Easyspin::Reset(void)
{
    reset = 0;
}

/******************************************************//**
 * @brief  Set the stepping mode
 * @param[in] shieldId (from 0 to 2)
 * @param[in] stepMod from full step to 1/16 microstep as specified in enum Easyspin_STEP_SEL_t
 * @retval None
 **********************************************************/
void Easyspin::SelectStepMode(uint8_t shieldId, Easyspin_STEP_SEL_t stepMod)
{
    uint8_t stepModeRegister;

    /* Eventually deactivate motor */
    if (shieldPrm[shieldId].motionState != INACTIVE) {
        HardStop(shieldId);
    }

    /* Read Step mode register and clear STEP_SEL field */
    stepModeRegister = (uint8_t)(0xF8 & CmdGetParam(shieldId,Easyspin_STEP_MODE)) ;

    /* Apply new step mode */
    CmdSetParam(shieldId, Easyspin_STEP_MODE, stepModeRegister | (uint8_t)stepMod);

    /* Reset abs pos register */
    SetHome(shieldId);
}

/******************************************************//**
 * @brief  Specifies the direction
 * @param[in] shieldId (from 0 to 2)
 * @param[in] dir FORWARD or BACKWARD
 * @note The direction change is only applied if the shield
 * is in INACTIVE state
 * @retval None
 **********************************************************/
void Easyspin::SetDirection(uint8_t shieldId, dir_t dir)
{
    if (shieldPrm[shieldId].motionState == INACTIVE) {
        shieldPrm[shieldId].direction = dir;

        switch (shieldId) {
            case 2:
                dir3 = dir;
                break;
            case 1:
                dir2 = dir;
                break;
            case 0:
                dir1 = dir;
                break;
            default:
                ;
        }
    }
}

/******************************************************//**
 * @brief  Gets the pointer to the Easyspin instance
 * @param  None
 * @retval Pointer to the instance of Easyspin
  **********************************************************/
class Easyspin* Easyspin::GetInstancePtr(void)
{
    return (class Easyspin*)instancePtr;
}

/******************************************************//**
 * @brief  Handles the shield state machine at each ste
 * @param[in] shieldId (from 0 to 2)
 * @retval None
 * @note Must only be called by the timer ISR
 **********************************************************/
void Easyspin::StepClockHandler(uint8_t shieldId)
{
    /* Set isr flag */
    isrFlag = true;

    /* Incrementation of the relative position */
    shieldPrm[shieldId].relativePos++;

    /* Periodically check that estimated position is correct */
    if ((shieldPrm[shieldId].commandExecuted != RUN_CMD) &&
            ((shieldPrm[shieldId].relativePos % 10) == 00)) {
        uint32_t AbsPos= ConvertPosition(CmdGetParam(shieldId,Easyspin_ABS_POS));

        /* Correct estimated position if needed */
        if (AbsPos != 0) {
            if ((shieldPrm[shieldId].direction == FORWARD) &&
                    (AbsPos != shieldPrm[shieldId].currentPosition + shieldPrm[shieldId].relativePos)) {
#ifdef _DEBUG_Easyspin
                snprintf(EasyspinStrOut, DEBUG_BUFFER_SIZE, "F EstPos:%ld RealPos: %ld\n",shieldPrm[shieldId].relativePos,(AbsPos - shieldPrm[shieldId].currentPosition));
                Serial.println(EasyspinStrOut);
#endif
                shieldPrm[shieldId].relativePos = AbsPos - shieldPrm[shieldId].currentPosition;

            } else if ((shieldPrm[shieldId].direction == BACKWARD) &&
                       (AbsPos != shieldPrm[shieldId].currentPosition - shieldPrm[shieldId].relativePos)) {
#ifdef _DEBUG_Easyspin
                snprintf(EasyspinStrOut, DEBUG_BUFFER_SIZE, "B EstPos:%ld RealPos: %ld\n",shieldPrm[shieldId].relativePos,(AbsPos - shieldPrm[shieldId].currentPosition));
                Serial.println(EasyspinStrOut);
#endif
                shieldPrm[shieldId].relativePos = shieldPrm[shieldId].currentPosition - AbsPos;
            }
        }
    }

    switch (shieldPrm[shieldId].motionState) {
        case ACCELERATING: {
            if ((shieldPrm[shieldId].commandExecuted == SOFT_STOP_CMD)||
                    ((shieldPrm[shieldId].commandExecuted != RUN_CMD)&&
                     (shieldPrm[shieldId].relativePos == shieldPrm[shieldId].startDecPos))) {
                shieldPrm[shieldId].motionState = DECELERATING;
                shieldPrm[shieldId].accu = 0;
#ifdef _DEBUG_Easyspin
                snprintf(EasyspinStrOut, DEBUG_BUFFER_SIZE, "Acc->Dec: speed: %u relativepos: %ld \n",shieldPrm[shieldId].speed,shieldPrm[shieldId].relativePos);
                Serial.println(EasyspinStrOut);
#endif
            } else if ((shieldPrm[shieldId].speed >= shieldPrm[shieldId].maxSpeed)||
                       ((shieldPrm[shieldId].commandExecuted != RUN_CMD)&&
                        (shieldPrm[shieldId].relativePos == shieldPrm[shieldId].endAccPos))) {
                shieldPrm[shieldId].motionState = STEADY;
#ifdef _DEBUG_Easyspin
                snprintf(EasyspinStrOut, DEBUG_BUFFER_SIZE, "Acc->Steady: speed: %u relativepos: %ld \n",shieldPrm[shieldId].speed,shieldPrm[shieldId].relativePos);
                Serial.println(EasyspinStrOut);
#endif
            } else {
                bool speedUpdated = false;
                /* Go on accelerating */
                shieldPrm[shieldId].accu += ((uint32_t)shieldPrm[shieldId].acceleration << 16) / shieldPrm[shieldId].speed;
                while (shieldPrm[shieldId].accu >= (0X10000L)) {
                    shieldPrm[shieldId].accu -= (0X10000L);
                    shieldPrm[shieldId].speed +=1;
                    speedUpdated = true;
                }

                if (speedUpdated) {
                    ApplySpeed(shieldId, shieldPrm[shieldId].speed);
                }
            }
            break;
        }
        case STEADY: {
            if  ((shieldPrm[shieldId].commandExecuted == SOFT_STOP_CMD)||
                    ((shieldPrm[shieldId].commandExecuted != RUN_CMD)&&
                     (shieldPrm[shieldId].relativePos >= (shieldPrm[shieldId].startDecPos))) ||
                    ((shieldPrm[shieldId].commandExecuted == RUN_CMD)&&
                     (shieldPrm[shieldId].speed > shieldPrm[shieldId].maxSpeed))) {
                shieldPrm[shieldId].motionState = DECELERATING;
                shieldPrm[shieldId].accu = 0;
            } else if ((shieldPrm[shieldId].commandExecuted == RUN_CMD)&&
                       (shieldPrm[shieldId].speed < shieldPrm[shieldId].maxSpeed)) {
                shieldPrm[shieldId].motionState = ACCELERATING;
                shieldPrm[shieldId].accu = 0;
            }
            break;
        }
        case DECELERATING: {
            if (((shieldPrm[shieldId].commandExecuted == SOFT_STOP_CMD)&&(shieldPrm[shieldId].speed <=  shieldPrm[shieldId].minSpeed))||
                    ((shieldPrm[shieldId].commandExecuted != RUN_CMD)&&
                     (shieldPrm[shieldId].relativePos >= shieldPrm[shieldId].stepsToTake))) {
                /* Motion process complete */
                HardStop(shieldId);
#ifdef _DEBUG_Easyspin
                snprintf(EasyspinStrOut, DEBUG_BUFFER_SIZE, "Dec->Stop: speed: %u relativepos: %ld \n",shieldPrm[shieldId].speed,shieldPrm[shieldId].relativePos );
                Serial.println(EasyspinStrOut);
#endif
            } else if ((shieldPrm[shieldId].commandExecuted == RUN_CMD)&&
                       (shieldPrm[shieldId].speed <= shieldPrm[shieldId].maxSpeed)) {
                shieldPrm[shieldId].motionState = STEADY;
#ifdef _DEBUG_Easyspin
                snprintf(EasyspinStrOut, DEBUG_BUFFER_SIZE, "Dec->Steady: speed: %u relativepos: %ld \n",shieldPrm[shieldId].speed,shieldPrm[shieldId].relativePos);
                Serial.println(EasyspinStrOut);
#endif
            } else {
                /* Go on decelerating */
                if (shieldPrm[shieldId].speed > shieldPrm[shieldId].minSpeed) {
                    bool speedUpdated = false;
                    shieldPrm[shieldId].accu += ((uint32_t)shieldPrm[shieldId].deceleration << 16) / shieldPrm[shieldId].speed;
                    while (shieldPrm[shieldId].accu >= (0X10000L)) {
                        shieldPrm[shieldId].accu -= (0X10000L);
                        shieldPrm[shieldId].speed -=1;
                        speedUpdated = true;
                    }
                    if (speedUpdated) {
                        ApplySpeed(shieldId, shieldPrm[shieldId].speed);
                    }
                }
            }
            break;
        }
        default: {
            break;
        }
    }
    /* Set isr flag */
    isrFlag = false;
}

/******************************************************//**
 * @brief  Updates the current speed of the shield
 * @param[in] shieldId (from 0 to 2)
 * @param[in] newSpeed in pps
 * @retval None
 **********************************************************/
void Easyspin::ApplySpeed(uint8_t shieldId, uint16_t newSpeed)
{
    if (newSpeed < Easyspin_MIN_PWM_FREQ) {
        newSpeed = Easyspin_MIN_PWM_FREQ;
    }
    if (newSpeed > Easyspin_MAX_PWM_FREQ) {
        newSpeed = Easyspin_MAX_PWM_FREQ;
    }

    shieldPrm[shieldId].speed = newSpeed;

    switch (shieldId) {
        case  0:
            Pwm1SetFreq(newSpeed);
            break;
        case 1:
            Pwm2SetFreq(newSpeed);
            break;
        case 2:
            Pwm3SetFreq(newSpeed);
            break;
        default:
            break; //ignore error
    }
}

/******************************************************//**
 * @brief  Computes the speed profile according to the number of steps to move
 * @param[in] shieldId (from 0 to 2)
 * @param[in] nbSteps number of steps to perform
 * @retval None
 * @note Using the acceleration and deceleration of the shield,
 * this function determines the duration in steps of the acceleration,
 * steady and deceleration phases.
 * If the total number of steps to perform is big enough, a trapezoidal move
 * is performed (i.e. there is a steady phase where the motor runs at the maximum
 * speed.
 * Else, a triangular move is performed (no steady phase: the maximum speed is never
 * reached.
 **********************************************************/
void Easyspin::ComputeSpeedProfile(uint8_t shieldId, uint32_t nbSteps)
{
    uint32_t reqAccSteps;
    uint32_t reqDecSteps;

    /* compute the number of steps to get the targeted speed */
    reqAccSteps = (shieldPrm[shieldId].maxSpeed - shieldPrm[shieldId].minSpeed);
    reqAccSteps *= (shieldPrm[shieldId].maxSpeed + shieldPrm[shieldId].minSpeed);
    reqDecSteps = reqAccSteps;
    reqAccSteps /= (uint32_t)shieldPrm[shieldId].acceleration;
    reqAccSteps /= 2;

    /* compute the number of steps to stop */
    reqDecSteps /= (uint32_t)shieldPrm[shieldId].deceleration;
    reqDecSteps /= 2;

    if(( reqAccSteps + reqDecSteps ) > nbSteps) {
        /* Triangular move  */
        /* reqDecSteps = (Pos * Dec) /(Dec+Acc) */

        reqDecSteps =  ((uint32_t) shieldPrm[shieldId].deceleration * nbSteps) / (shieldPrm[shieldId].acceleration + shieldPrm[shieldId].deceleration);
        if (reqDecSteps > 1) {
            reqAccSteps = reqDecSteps - 1;
            if(reqAccSteps == 0) {
                reqAccSteps = 1;
            }
        } else {
            reqAccSteps = 0;
        }
        shieldPrm[shieldId].endAccPos = reqAccSteps;
        shieldPrm[shieldId].startDecPos = reqDecSteps;
    } else {
        /* Trapezoidal move */
        /* accelerating phase to endAccPos */
        /* steady phase from  endAccPos to startDecPos */
        /* decelerating from startDecPos to stepsToTake*/
        shieldPrm[shieldId].endAccPos = reqAccSteps;
        shieldPrm[shieldId].startDecPos = nbSteps - reqDecSteps - 1;
    }
}

/******************************************************//**
 * @brief  Converts the ABS_POSITION register value to a 32b signed integer
 * @param[in] abs_position_reg value of the ABS_POSITION register
 * @retval operation_result 32b signed integer corresponding to the absolute position
 **********************************************************/
int32_t Easyspin::ConvertPosition(uint32_t abs_position_reg)
{
    int32_t operation_result;

    if (abs_position_reg & Easyspin_ABS_POS_SIGN_BIT_MASK) {
        /* Negative register value */
        abs_position_reg = ~abs_position_reg;
        abs_position_reg += 1;

        operation_result = (int32_t) (abs_position_reg & Easyspin_ABS_POS_VALUE_MASK);
        operation_result = -operation_result;
    } else {
        operation_result = (int32_t) abs_position_reg;
    }
    return operation_result;
}

/******************************************************//**
 * @brief  Handlers of the flag interrupt which calls the user callback (if defined)
 * @param None
 * @retval None
 **********************************************************/
void Easyspin::FlagInterruptHandler(void)
{
    if (flagInterruptCallback != NULL) {
        /* Set isr flag */
        isrFlag = true;

        flagInterruptCallback();

        /* Reset isr flag */
        isrFlag = false;
    }
}

/******************************************************//**
 * @brief  Sends a command without arguments to the Easyspin via the SPI
 * @param[in] shieldId (from 0 to 2)
 * @param[in] param Command to send
 * @retval None
 **********************************************************/
void Easyspin::SendCommand(uint8_t shieldId, uint8_t param)
{
    uint8_t spiIndex = numberOfShields - shieldId - 1;
    bool itDisable = false;

    do {
        spiPreemtionByIsr = false;
        if (itDisable) {
            /* re-enable interrupts if disable in previous iteration */
            flag.enable_irq();
            itDisable = false;
        }

        for (uint32_t i = 0; i < numberOfShields; i++) {
            spiTxBursts[3][i] = Easyspin_NOP;
        }
        spiTxBursts[3][spiIndex] = param;

        /* Disable interruption before checking */
        /* pre-emption by ISR and SPI transfers*/
        flag.disable_irq();
        itDisable = true;
    } while (spiPreemtionByIsr); // check pre-emption by ISR

    WriteBytes(&spiTxBursts[3][0], &spiRxBursts[3][0]);

    /* re-enable interrupts after SPI transfers*/
    flag.enable_irq();
}

/******************************************************//**
 * @brief  Sets the registers of the Easyspin to their predefined values
 * from Easyspin_target_config.h
 * @param[in] shieldId (from 0 to 2)
 * @retval None
 **********************************************************/
void Easyspin::SetRegisterToPredefinedValues(uint8_t shieldId)
{
    CmdSetParam(shieldId,
                Easyspin_ABS_POS,
                0);
    CmdSetParam(shieldId,
                Easyspin_EL_POS,
                0);
    CmdSetParam(shieldId,
                Easyspin_MARK,
                0);
    switch (shieldId) {
        case 0:
            CmdSetParam(shieldId,
                        Easyspin_TVAL,
                        Tval_Current_to_Par(Easyspin_CONF_PARAM_TVAL_SHIELD_0));
            CmdSetParam(shieldId,
                        Easyspin_T_FAST,
                        (uint8_t)Easyspin_CONF_PARAM_TOFF_FAST_SHIELD_0 |
                        (uint8_t)Easyspin_CONF_PARAM_FAST_STEP_SHIELD_0);
            CmdSetParam(shieldId,
                        Easyspin_TON_MIN,
                        Tmin_Time_to_Par(Easyspin_CONF_PARAM_TON_MIN_SHIELD_0));
            CmdSetParam(shieldId,
                        Easyspin_TOFF_MIN,
                        Tmin_Time_to_Par(Easyspin_CONF_PARAM_TOFF_MIN_SHIELD_0));
            CmdSetParam(shieldId,
                        Easyspin_OCD_TH,
                        Easyspin_CONF_PARAM_OCD_TH_SHIELD_0);
            CmdSetParam(shieldId,
                        Easyspin_STEP_MODE,
                        (uint8_t)Easyspin_CONF_PARAM_STEP_SEL_SHIELD_0 |
                        (uint8_t)Easyspin_CONF_PARAM_SYNC_SEL_SHIELD_0);
            CmdSetParam(shieldId,
                        Easyspin_ALARM_EN,
                        Easyspin_CONF_PARAM_ALARM_EN_SHIELD_0);
            CmdSetParam(shieldId,
                        Easyspin_CONFIG,
                        (uint16_t)Easyspin_CONF_PARAM_CLOCK_SETTING_SHIELD_0 |
                        (uint16_t)Easyspin_CONF_PARAM_TQ_REG_SHIELD_0 |
                        (uint16_t)Easyspin_CONF_PARAM_OC_SD_SHIELD_0 |
                        (uint16_t)Easyspin_CONF_PARAM_SR_SHIELD_0 |
                        (uint16_t)Easyspin_CONF_PARAM_TOFF_SHIELD_0);
            break;
        case 1:
            CmdSetParam(shieldId,
                        Easyspin_TVAL,
                        Tval_Current_to_Par(Easyspin_CONF_PARAM_TVAL_SHIELD_1));
            CmdSetParam(shieldId,
                        Easyspin_T_FAST,
                        (uint8_t)Easyspin_CONF_PARAM_TOFF_FAST_SHIELD_1 |
                        (uint8_t)Easyspin_CONF_PARAM_FAST_STEP_SHIELD_1);
            CmdSetParam(shieldId,
                        Easyspin_TON_MIN,
                        Tmin_Time_to_Par(Easyspin_CONF_PARAM_TON_MIN_SHIELD_1));
            CmdSetParam(shieldId,
                        Easyspin_TOFF_MIN,
                        Tmin_Time_to_Par(Easyspin_CONF_PARAM_TOFF_MIN_SHIELD_1));
            CmdSetParam(shieldId,
                        Easyspin_OCD_TH,
                        Easyspin_CONF_PARAM_OCD_TH_SHIELD_1);
            CmdSetParam(shieldId,
                        Easyspin_STEP_MODE,
                        (uint8_t)Easyspin_CONF_PARAM_STEP_SEL_SHIELD_1 |
                        (uint8_t)Easyspin_CONF_PARAM_SYNC_SEL_SHIELD_1);
            CmdSetParam(shieldId,
                        Easyspin_ALARM_EN,
                        Easyspin_CONF_PARAM_ALARM_EN_SHIELD_1);
            CmdSetParam(shieldId,
                        Easyspin_CONFIG,
                        (uint16_t)Easyspin_CONF_PARAM_CLOCK_SETTING_SHIELD_1 |
                        (uint16_t)Easyspin_CONF_PARAM_TQ_REG_SHIELD_1 |
                        (uint16_t)Easyspin_CONF_PARAM_OC_SD_SHIELD_1 |
                        (uint16_t)Easyspin_CONF_PARAM_SR_SHIELD_1 |
                        (uint16_t)Easyspin_CONF_PARAM_TOFF_SHIELD_1);
            break;
        case 2:
            CmdSetParam(shieldId,
                        Easyspin_TVAL,
                        Tval_Current_to_Par(Easyspin_CONF_PARAM_TVAL_SHIELD_2));
            CmdSetParam(shieldId,
                        Easyspin_T_FAST,
                        (uint8_t)Easyspin_CONF_PARAM_TOFF_FAST_SHIELD_2 |
                        (uint8_t)Easyspin_CONF_PARAM_FAST_STEP_SHIELD_2);
            CmdSetParam(shieldId,
                        Easyspin_TON_MIN,
                        Tmin_Time_to_Par(Easyspin_CONF_PARAM_TON_MIN_SHIELD_2));
            CmdSetParam(shieldId,
                        Easyspin_TOFF_MIN,
                        Tmin_Time_to_Par(Easyspin_CONF_PARAM_TOFF_MIN_SHIELD_2));
            CmdSetParam(shieldId,
                        Easyspin_OCD_TH,
                        Easyspin_CONF_PARAM_OCD_TH_SHIELD_2);
            CmdSetParam(shieldId,
                        Easyspin_STEP_MODE,
                        (uint8_t)Easyspin_CONF_PARAM_STEP_SEL_SHIELD_2 |
                        (uint8_t)Easyspin_CONF_PARAM_SYNC_SEL_SHIELD_2);
            CmdSetParam(shieldId,
                        Easyspin_ALARM_EN,
                        Easyspin_CONF_PARAM_ALARM_EN_SHIELD_2);
            CmdSetParam(shieldId,
                        Easyspin_CONFIG,
                        (uint16_t)Easyspin_CONF_PARAM_CLOCK_SETTING_SHIELD_2 |
                        (uint16_t)Easyspin_CONF_PARAM_TQ_REG_SHIELD_2 |
                        (uint16_t)Easyspin_CONF_PARAM_OC_SD_SHIELD_2 |
                        (uint16_t)Easyspin_CONF_PARAM_SR_SHIELD_2 |
                        (uint16_t)Easyspin_CONF_PARAM_TOFF_SHIELD_2);
            break;
        default:
            ;
    }
}

/******************************************************//**
 * @brief  Sets the registers of the Easyspin to their predefined values
 * from Easyspin_target_config.h
 * @param[in] shieldId (from 0 to 2)
 * @retval None
 **********************************************************/
void Easyspin::WriteBytes(uint8_t *pByteToTransmit, uint8_t *pReceivedByte)
{
    CS = 0;
    for (uint32_t i = 0; i < numberOfShields; i++) {
        *pReceivedByte = spi.write(*pByteToTransmit);
        pByteToTransmit++;
        pReceivedByte++;
    }
    CS = 1;
    if (isrFlag) {
        spiPreemtionByIsr = true;
    }
}

/******************************************************//**
 * @brief  Initialises the PWM uses by the specified shield
 * @param[in] shieldId (from 0 to 2)
 * @retval None
 * @note Shield 0 uses PW1 based on timer 1
 * Shield 1 uses PWM 2 based on timer 2
 * Shield 2 uses PWM3 based timer 0
 **********************************************************/
void Easyspin::PwmInit(uint8_t shieldId)
{
    switch (shieldId) {
        case 0:
            /* PWM1 uses timer 1 */
            /* Initialise timer by setting waveform generation mode
            to PWM phase and Frequency correct: mode = 8
            (WGM10 = 0, WGM11 = 0, WGM12 = 0, WGM13 = 1) */

            /* Stop timer1 by clearing CSS bits and set WGM13 and WGM12 */
            //TCCR1B = 0x10;

            /* Set WGM10 and WGM11 */
            //TCCR1A =  0x00;

            /*  Disable Timer1 interrupt */
            //TIMSK1 = 0;
            //pwm1.period_us(400);
            //pwm1.pulsewidth_us(200);

            break;
        case  1:
            /* PWM2 uses timer 2 */
            /* Initialise timer by setting waveform generation mode
            to PWM phase correct: mode = 5
            (WGM0 = 1, WGM21 = 0, WGM22 = 1) */

            /* Stop timer2 by clearing CSS bits and set WGM22 */
            //TCCR2B = 0x08;

            /* Set WGM20 and WGM21 */
            //TCCR2A =  0x01;

            /*  Disable Timer2 interrupt */
            //TIMSK2 = 0;
            //pwm2.period_us(500);
            //pwm2.pulsewidth_us(100);
            break;


        case 2:
            /* PWM3 uses timer 0 */
            /* !!!!! Caution: Calling this configuration will break */
            /* all default Arduino's timing functions as delay(),millis()... */

            /* Initialise timer by setting waveform generation mode
            to PWM phase correct: mode = 5
            (WGM0 = 1, WGM21 = 0, WGM22 = 1) */

            /* Stop timer0 by clearing CSS bits and set WGM22 */
            //TCCR0B = 0x08;

            /* Set WGM00 and WGM01 */
            //TCCR0A =  0x01;

            /*  Disable Timer0 interrupt */
            //TIMSK0 = 0;
            //pwm3.period_ms(10);
            //pwm3.pulsewidth_ms(1);
            break;
        default:
            break;//ignore error
    }
}

/******************************************************//**
 * @brief Ticker1
 * @param[in]
 * @retval
 **********************************************************/
void Easyspin::tick1()
{
    class Easyspin* instancePtr = Easyspin::GetInstancePtr();
    pwm1 = !pwm1;
    if (instancePtr != NULL) {
        if (instancePtr->GetShieldState(0) != INACTIVE) {
            instancePtr->StepClockHandler(0);
        }
    }
}

/******************************************************//**
 * @brief Ticker2
 * @param[in]
 * @retval
 **********************************************************/
void Easyspin::tick2()
{
    class Easyspin* instancePtr = Easyspin::GetInstancePtr();
    pwm2 = !pwm2;
    if (instancePtr != NULL) {
        if (instancePtr->GetShieldState(1) != INACTIVE) {
            instancePtr->StepClockHandler(1);
        }
    }
}

/******************************************************//**
 * @brief  Sets the frequency of PWM1 used by shield 0
 * @param[in] newFreq in Hz
 * @retval None
 * @note The frequency is directly the current speed of the shield
 **********************************************************/
void Easyspin::Pwm1SetFreq(uint16_t newFreq)
{
    uint16_t us;
    us = (1000000 / (newFreq * 2));
    ticker1.attach_us(this, &Easyspin::tick1, us);
}

/******************************************************//**
 * @brief  Sets the frequency of PWM2 used by shield 1
 * @param[in] newFreq in Hz
 * @retval None
 * @note The frequency is directly the current speed of the shield
 **********************************************************/
void Easyspin::Pwm2SetFreq(uint16_t newFreq)
{
    uint16_t us;
    us = (1000000 / (newFreq * 2));
    ticker2.attach_us(this, &Easyspin::tick2, us);
}

/******************************************************//**
 * @brief  Sets the frequency of PWM3 used by shield 2
 * @param[in] newFreq in Hz
 * @retval None
 * @note The frequency is directly the current speed of the shield
 **********************************************************/
void Easyspin::Pwm3SetFreq(uint16_t newFreq)
{

}

/******************************************************//**
 * @brief  Stops the PWM uses by the specified shield
 * @param[in] shieldId (from 0 to 2)
 * @retval None
 **********************************************************/
void Easyspin::PwmStop(uint8_t shieldId)
{
    switch (shieldId) {
        case 0:
            ticker1.detach();
            break;
        case  1:
            ticker2.detach();
            break;
        case 2:
            ticker3.detach();
            break;
        default:
            break;//ignore error
    }
}

/******************************************************//**
 * @brief  Sets the parameters of the shield to predefined values
 * from Easyspin_target_config.h
 * @param None
 * @retval None
 **********************************************************/
void Easyspin::SetShieldParamsToPredefinedValues(void)
{
    shieldPrm[0].acceleration = Easyspin_CONF_PARAM_ACC_SHIELD_0;
    shieldPrm[0].deceleration = Easyspin_CONF_PARAM_DEC_SHIELD_0;
    shieldPrm[0].maxSpeed = Easyspin_CONF_PARAM_MAX_SPEED_SHIELD_0;
    shieldPrm[0].minSpeed = Easyspin_CONF_PARAM_MIN_SPEED_SHIELD_0;

    shieldPrm[1].acceleration = Easyspin_CONF_PARAM_ACC_SHIELD_1;
    shieldPrm[1].deceleration = Easyspin_CONF_PARAM_DEC_SHIELD_1;
    shieldPrm[1].maxSpeed = Easyspin_CONF_PARAM_MAX_SPEED_SHIELD_1;
    shieldPrm[1].minSpeed = Easyspin_CONF_PARAM_MIN_SPEED_SHIELD_1;

    shieldPrm[2].acceleration = Easyspin_CONF_PARAM_ACC_SHIELD_2;
    shieldPrm[2].deceleration = Easyspin_CONF_PARAM_DEC_SHIELD_2;
    shieldPrm[2].maxSpeed = Easyspin_CONF_PARAM_MAX_SPEED_SHIELD_2;
    shieldPrm[2].minSpeed = Easyspin_CONF_PARAM_MIN_SPEED_SHIELD_2;

    for (uint8_t i = 0; i < numberOfShields; i++) {
        SetRegisterToPredefinedValues(i);
    }
}

/******************************************************//**
 * @brief Initialises the bridge parameters to start the movement
 * and enable the power bridge
 * @param[in] shieldId (from 0 to 2)
 * @retval None
 **********************************************************/
void Easyspin::StartMovement(uint8_t shieldId)
{
    /* Enable Easyspin powerstage */
    CmdEnable(shieldId);

    if (shieldPrm[shieldId].endAccPos != 0) {
        shieldPrm[shieldId].motionState = ACCELERATING;;
    } else {
        shieldPrm[shieldId].motionState = DECELERATING;
    }

    shieldPrm[shieldId].accu = 0;
    shieldPrm[shieldId].relativePos = 0;
    ApplySpeed(shieldId, shieldPrm[shieldId].minSpeed);
#ifdef _DEBUG_Easyspin
    snprintf(EasyspinStrOut, DEBUG_BUFFER_SIZE, "Stop->Acc: speed: %u relPos: %ld\n", shieldPrm[shieldId].minSpeed, shieldPrm[shieldId].relativePos) ;
    Serial.println(EasyspinStrOut);
#endif
}

/******************************************************//**
 * @brief Converts mA in compatible values for TVAL register
 * @param[in] Tval
 * @retval TVAL values
 **********************************************************/
inline uint8_t Easyspin::Tval_Current_to_Par(double Tval)
{
    return ((uint8_t)(((Tval - 31.25)/31.25)+0.5));
}

/******************************************************//**
 * @brief Convert time in us in compatible values
 * for TON_MIN register
 * @param[in] Tmin
 * @retval TON_MIN values
 **********************************************************/
inline uint8_t Easyspin::Tmin_Time_to_Par(double Tmin)
{
    return ((uint8_t)(((Tmin - 0.5)*2)+0.5));
}