Momentum-Apps/lib/ST25RFAL002/source/st25r3916/st25r3916.c

/******************************************************************************
  * \attention
  *
  * <h2><center>&copy; COPYRIGHT 2020 STMicroelectronics</center></h2>
  *
  * Licensed under ST MYLIBERTY SOFTWARE LICENSE AGREEMENT (the "License");
  * You may not use this file except in compliance with the License.
  * You may obtain a copy of the License at:
  *
  *        www.st.com/myliberty
  *
  * Unless required by applicable law or agreed to in writing, software 
  * distributed under the License is distributed on an "AS IS" BASIS, 
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied,
  * AND SPECIFICALLY DISCLAIMING THE IMPLIED WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  *
******************************************************************************/


/*
 *      PROJECT:   ST25R3916 firmware
 *      Revision: 
 *      LANGUAGE:  ISO C99
 */

/*! \file
 *
 *  \author Gustavo Patricio
 *
 *  \brief ST25R3916 high level interface
 *
 */

/*
******************************************************************************
* INCLUDES
******************************************************************************
*/

#include "st25r3916.h"
#include "st25r3916_com.h"
#include "st25r3916_led.h"
#include "st25r3916_irq.h"
#include "utils.h"



/*
******************************************************************************
* LOCAL DEFINES
******************************************************************************
*/

#define ST25R3916_SUPPLY_THRESHOLD                3600U   /*!< Power supply measure threshold between 3.3V or 5V                   */
#define ST25R3916_NRT_MAX                         0xFFFFU /*!< Max Register value of NRT                                           */
                                                  
#define ST25R3916_TOUT_MEASURE_VDD                100U    /*!< Max duration time of Measure Power Supply command  Datasheet: 25us  */
#define ST25R3916_TOUT_MEASURE_AMPLITUDE          10U     /*!< Max duration time of Measure Amplitude command     Datasheet: 25us  */
#define ST25R3916_TOUT_MEASURE_PHASE              10U     /*!< Max duration time of Measure Phase command         Datasheet: 25us  */
#define ST25R3916_TOUT_MEASURE_CAPACITANCE        10U     /*!< Max duration time of Measure Capacitance command   Datasheet: 25us  */
#define ST25R3916_TOUT_CALIBRATE_CAP_SENSOR       4U      /*!< Max duration Calibrate Capacitive Sensor command   Datasheet: 3ms   */
#define ST25R3916_TOUT_ADJUST_REGULATORS          6U      /*!< Max duration time of Adjust Regulators command     Datasheet: 5ms   */
#define ST25R3916_TOUT_CA                         10U     /*!< Max duration time of Collision Avoidance command                    */
                                                  
#define ST25R3916_TEST_REG_PATTERN                0x33U   /*!< Register Read Write test pattern used during selftest               */
#define ST25R3916_TEST_WU_TOUT                    12U     /*!< Timeout used on WU timer during self test                           */
#define ST25R3916_TEST_TMR_TOUT                   20U     /*!< Timeout used during self test                                       */
#define ST25R3916_TEST_TMR_TOUT_DELTA             2U      /*!< Timeout used during self test                                       */
#define ST25R3916_TEST_TMR_TOUT_8FC               (ST25R3916_TEST_TMR_TOUT * 16950U) /*!< Timeout in 8/fc                          */

/*
******************************************************************************
* LOCAL CONSTANTS
******************************************************************************
*/

/*
******************************************************************************
* LOCAL VARIABLES
******************************************************************************
*/

static uint32_t gST25R3916NRT_64fcs;

/*
******************************************************************************
* LOCAL FUNCTION PROTOTYPES
******************************************************************************
*/

/*
 ******************************************************************************
 * LOCAL FUNCTION
 ******************************************************************************
 */

ReturnCode st25r3916ExecuteCommandAndGetResult( uint8_t cmd, uint8_t resReg, uint8_t tout, uint8_t* result )
{
    /* Clear and enable Direct Command interrupt */
    st25r3916GetInterrupt( ST25R3916_IRQ_MASK_DCT );
    st25r3916EnableInterrupts( ST25R3916_IRQ_MASK_DCT );

    st25r3916ExecuteCommand( cmd );

    st25r3916WaitForInterruptsTimed( ST25R3916_IRQ_MASK_DCT, tout );
    st25r3916DisableInterrupts( ST25R3916_IRQ_MASK_DCT );

    /* After execution read out the result if the pointer is not NULL */
    if( result != NULL )
    {
        st25r3916ReadRegister( resReg, result);
    }

    return ERR_NONE;

}

/*
******************************************************************************
* GLOBAL FUNCTIONS
******************************************************************************
*/

ReturnCode st25r3916Initialize( void )
{
    uint16_t vdd_mV;
    ReturnCode ret;

    /* Set default state on the ST25R3916 */
    st25r3916ExecuteCommand( ST25R3916_CMD_SET_DEFAULT );

#ifndef RFAL_USE_I2C
    /* Increase MISO driving level as SPI can go up to 10MHz */
    st25r3916WriteRegister(ST25R3916_REG_IO_CONF2, ST25R3916_REG_IO_CONF2_io_drv_lvl);
#endif /* RFAL_USE_I2C */

    if( !st25r3916CheckChipID( NULL ) )
    {
        platformErrorHandle();
        return ERR_HW_MISMATCH;
    }

    st25r3916InitInterrupts();
    st25r3916ledInit();
    

    gST25R3916NRT_64fcs = 0;

#ifndef RFAL_USE_I2C
    /* Enable pull downs on MISO line */
    st25r3916SetRegisterBits(ST25R3916_REG_IO_CONF2, ( ST25R3916_REG_IO_CONF2_miso_pd1 | ST25R3916_REG_IO_CONF2_miso_pd2 ) );
#endif /* RFAL_USE_I2C */

    /* Disable internal overheat protection */
    st25r3916ChangeTestRegisterBits( 0x04, 0x10, 0x10 );

#ifdef ST25R_SELFTEST
    /******************************************************************************
     * Check communication interface: 
     *  - write a pattern in a register
     *  - reads back the register value
     *  - return ERR_IO in case the read value is different
     */
    st25r3916WriteRegister( ST25R3916_REG_BIT_RATE, ST25R3916_TEST_REG_PATTERN );
    if( !st25r3916CheckReg( ST25R3916_REG_BIT_RATE, (ST25R3916_REG_BIT_RATE_rxrate_mask | ST25R3916_REG_BIT_RATE_txrate_mask), ST25R3916_TEST_REG_PATTERN ) )
    {
        platformErrorHandle();
        return ERR_IO;
    }
    
    /* Restore default value */
    st25r3916WriteRegister( ST25R3916_REG_BIT_RATE, 0x00 );

    /*
     * Check IRQ Handling:
     *  - use the Wake-up timer to trigger an IRQ
     *  - wait the Wake-up timer interrupt
     *  - return ERR_TIMEOUT when the Wake-up timer interrupt is not received
     */
    st25r3916WriteRegister( ST25R3916_REG_WUP_TIMER_CONTROL, ST25R3916_REG_WUP_TIMER_CONTROL_wur|ST25R3916_REG_WUP_TIMER_CONTROL_wto);
    st25r3916EnableInterrupts( ST25R3916_IRQ_MASK_WT );
    st25r3916ExecuteCommand( ST25R3916_CMD_START_WUP_TIMER );
    if(st25r3916WaitForInterruptsTimed(ST25R3916_IRQ_MASK_WT, ST25R3916_TEST_WU_TOUT) == 0U )
    {
        platformErrorHandle();
        return ERR_TIMEOUT;
    }
    st25r3916DisableInterrupts( ST25R3916_IRQ_MASK_WT );
    st25r3916WriteRegister( ST25R3916_REG_WUP_TIMER_CONTROL, 0U );
    /*******************************************************************************/
#endif /* ST25R_SELFTEST */

    /* Enable Oscillator and wait until it gets stable */
    ret = st25r3916OscOn();
    if( ret != ERR_NONE )
    {
        platformErrorHandle();
        return ret;
    }

    /* Measure VDD and set sup3V bit according to Power supplied  */
    vdd_mV = st25r3916MeasureVoltage( ST25R3916_REG_REGULATOR_CONTROL_mpsv_vdd );
    st25r3916ChangeRegisterBits( ST25R3916_REG_IO_CONF2, ST25R3916_REG_IO_CONF2_sup3V, ((vdd_mV < ST25R3916_SUPPLY_THRESHOLD) ? ST25R3916_REG_IO_CONF2_sup3V_3V : ST25R3916_REG_IO_CONF2_sup3V_5V) );

    /* Make sure Transmitter and Receiver are disabled */
    st25r3916TxRxOff();

    
#ifdef ST25R_SELFTEST_TIMER
    /******************************************************************************
     * Check SW timer operation :
     *  - use the General Purpose timer to measure an amount of time
     *  - test whether an interrupt is seen when less time was given
     *  - test whether an interrupt is seen when sufficient time was given
     */
    
    st25r3916EnableInterrupts( ST25R3916_IRQ_MASK_GPE );
    st25r3916SetStartGPTimer( (uint16_t)ST25R3916_TEST_TMR_TOUT_8FC, ST25R3916_REG_TIMER_EMV_CONTROL_gptc_no_trigger);
    if( st25r3916WaitForInterruptsTimed( ST25R3916_IRQ_MASK_GPE, (ST25R3916_TEST_TMR_TOUT - ST25R3916_TEST_TMR_TOUT_DELTA)) != 0U )
    {
        platformErrorHandle();
        return ERR_SYSTEM;
    }
    
    /* Stop all activities to stop the GP timer */
    st25r3916ExecuteCommand( ST25R3916_CMD_STOP );                                     
    st25r3916ClearAndEnableInterrupts( ST25R3916_IRQ_MASK_GPE );
    st25r3916SetStartGPTimer( (uint16_t)ST25R3916_TEST_TMR_TOUT_8FC, ST25R3916_REG_TIMER_EMV_CONTROL_gptc_no_trigger );
    if(st25r3916WaitForInterruptsTimed( ST25R3916_IRQ_MASK_GPE, (ST25R3916_TEST_TMR_TOUT + ST25R3916_TEST_TMR_TOUT_DELTA)) == 0U )
    {
        platformErrorHandle();
        return ERR_SYSTEM;
    }
    
    /* Stop all activities to stop the GP timer */
    st25r3916ExecuteCommand( ST25R3916_CMD_STOP );
    /*******************************************************************************/
#endif /* ST25R_SELFTEST_TIMER */

    
    /* After reset all interrupts are enabled, so disable them at first */
    st25r3916DisableInterrupts( ST25R3916_IRQ_MASK_ALL );

    /* And clear them, just to be sure */
    st25r3916ClearInterrupts();

    return ERR_NONE;
}


/*******************************************************************************/
void st25r3916Deinitialize( void )
{
    st25r3916DisableInterrupts( ST25R3916_IRQ_MASK_ALL );    

    /* Disabe Tx and Rx, Keep OSC On */
    st25r3916TxRxOff();

    return;
}


/*******************************************************************************/
ReturnCode st25r3916OscOn( void )
{
    /* Check if oscillator is already turned on and stable                                                */
    /* Use ST25R3916_REG_OP_CONTROL_en instead of ST25R3916_REG_AUX_DISPLAY_osc_ok to be on the safe side */
    if( !st25r3916CheckReg( ST25R3916_REG_OP_CONTROL, ST25R3916_REG_OP_CONTROL_en, ST25R3916_REG_OP_CONTROL_en ) )
    {
        /* Clear any eventual previous oscillator IRQ */
        st25r3916GetInterrupt( ST25R3916_IRQ_MASK_OSC );

        /* Enable oscillator frequency stable interrupt */
        st25r3916EnableInterrupts( ST25R3916_IRQ_MASK_OSC );

        /* Enable oscillator and regulator output */
        st25r3916SetRegisterBits( ST25R3916_REG_OP_CONTROL, ST25R3916_REG_OP_CONTROL_en );

        /* Wait for the oscillator interrupt */
        st25r3916WaitForInterruptsTimed( ST25R3916_IRQ_MASK_OSC, ST25R3916_TOUT_OSC_STABLE );
        st25r3916DisableInterrupts( ST25R3916_IRQ_MASK_OSC );
    }
    
    if( !st25r3916CheckReg( ST25R3916_REG_AUX_DISPLAY, ST25R3916_REG_AUX_DISPLAY_osc_ok, ST25R3916_REG_AUX_DISPLAY_osc_ok ) )
    {
        return ERR_SYSTEM;
    }
    
    return ERR_NONE;
}


/*******************************************************************************/
uint8_t st25r3916MeasurePowerSupply( uint8_t mpsv )
{
    uint8_t result; 
   
    /* Set the source of direct command: Measure Power Supply Voltage */
    st25r3916ChangeRegisterBits( ST25R3916_REG_REGULATOR_CONTROL, ST25R3916_REG_REGULATOR_CONTROL_mpsv_mask, mpsv );

    /* Execute command: Measure Power Supply Voltage */
    st25r3916ExecuteCommandAndGetResult( ST25R3916_CMD_MEASURE_VDD, ST25R3916_REG_AD_RESULT, ST25R3916_TOUT_MEASURE_VDD, &result);

    return result;
}


/*******************************************************************************/
uint16_t st25r3916MeasureVoltage( uint8_t mpsv )
{
    uint8_t result; 
    uint16_t mV;

    result = st25r3916MeasurePowerSupply(mpsv);
   
    /* Convert cmd output into mV (each step represents 23.4 mV )*/
    mV  = ((uint16_t)result) * 23U;
    mV += (((((uint16_t)result) * 4U) + 5U) / 10U);

    return mV;
}


/*******************************************************************************/
ReturnCode st25r3916AdjustRegulators( uint16_t* result_mV )
{
    uint8_t result;

    /* Reset logic and set regulated voltages to be defined by result of Adjust Regulators command */
    st25r3916SetRegisterBits( ST25R3916_REG_REGULATOR_CONTROL, ST25R3916_REG_REGULATOR_CONTROL_reg_s );
    st25r3916ClrRegisterBits( ST25R3916_REG_REGULATOR_CONTROL, ST25R3916_REG_REGULATOR_CONTROL_reg_s );

    /* Execute Adjust regulators cmd and retrieve result */
    st25r3916ExecuteCommandAndGetResult( ST25R3916_CMD_ADJUST_REGULATORS, ST25R3916_REG_REGULATOR_RESULT, ST25R3916_TOUT_ADJUST_REGULATORS, &result );

    /* Calculate result in mV */
    result >>= ST25R3916_REG_REGULATOR_RESULT_reg_shift;
    
    if( result_mV != NULL )
    {
        if( st25r3916CheckReg( ST25R3916_REG_IO_CONF2, ST25R3916_REG_IO_CONF2_sup3V, ST25R3916_REG_IO_CONF2_sup3V )  )
        {
            result = MIN( result, (uint8_t)(result-5U) );/* In 3.3V mode [0,4] are not used                       */
            *result_mV = 2400U;                          /* Minimum regulated voltage 2.4V in case of 3.3V supply */
        }
        else
        {
            *result_mV = 3600U;                          /* Minimum regulated voltage 3.6V in case of 5V supply   */
        }
        
        *result_mV += (uint16_t)result * 100U;           /* 100mV steps in both 3.3V and 5V supply                */
    }
    return ERR_NONE;
}


/*******************************************************************************/
ReturnCode st25r3916MeasureAmplitude( uint8_t* result )
{
    return st25r3916ExecuteCommandAndGetResult( ST25R3916_CMD_MEASURE_AMPLITUDE, ST25R3916_REG_AD_RESULT, ST25R3916_TOUT_MEASURE_AMPLITUDE, result );
}


/*******************************************************************************/
ReturnCode st25r3916MeasurePhase( uint8_t* result )
{
    return st25r3916ExecuteCommandAndGetResult( ST25R3916_CMD_MEASURE_PHASE, ST25R3916_REG_AD_RESULT, ST25R3916_TOUT_MEASURE_PHASE, result );
}


/*******************************************************************************/
ReturnCode st25r3916MeasureCapacitance( uint8_t* result )
{
    return st25r3916ExecuteCommandAndGetResult( ST25R3916_CMD_MEASURE_CAPACITANCE, ST25R3916_REG_AD_RESULT, ST25R3916_TOUT_MEASURE_CAPACITANCE, result );
}


/*******************************************************************************/
ReturnCode st25r3916CalibrateCapacitiveSensor( uint8_t* result )
{
    ReturnCode ret;
    uint8_t    res;
    
    /* Clear Manual calibration values to enable automatic calibration mode */
    st25r3916ClrRegisterBits( ST25R3916_REG_CAP_SENSOR_CONTROL, ST25R3916_REG_CAP_SENSOR_CONTROL_cs_mcal_mask );
    
    /* Execute automatic calibration */
    ret = st25r3916ExecuteCommandAndGetResult( ST25R3916_CMD_CALIBRATE_C_SENSOR, ST25R3916_REG_CAP_SENSOR_RESULT, ST25R3916_TOUT_CALIBRATE_CAP_SENSOR, &res );
    
    /* Check wether the calibration was successull */
    if( ((res & ST25R3916_REG_CAP_SENSOR_RESULT_cs_cal_end) != ST25R3916_REG_CAP_SENSOR_RESULT_cs_cal_end) ||
        ((res & ST25R3916_REG_CAP_SENSOR_RESULT_cs_cal_err) == ST25R3916_REG_CAP_SENSOR_RESULT_cs_cal_err) || (ret != ERR_NONE) )
    {
        return ERR_IO;
    }
    
    if( result != NULL )
    {
        (*result) = (uint8_t)(res >> ST25R3916_REG_CAP_SENSOR_RESULT_cs_cal_shift);
    }
    
    return ERR_NONE;
}


/*******************************************************************************/
ReturnCode st25r3916SetBitrate(uint8_t txrate, uint8_t rxrate)
{
    uint8_t reg;

    st25r3916ReadRegister( ST25R3916_REG_BIT_RATE, &reg );
    if( rxrate != ST25R3916_BR_DO_NOT_SET )
    {
        if(rxrate > ST25R3916_BR_848)
        {
            return ERR_PARAM;
        }

        reg = (uint8_t)(reg & ~ST25R3916_REG_BIT_RATE_rxrate_mask);     /* MISRA 10.3 */
        reg |= rxrate << ST25R3916_REG_BIT_RATE_rxrate_shift;
    }
    if( txrate != ST25R3916_BR_DO_NOT_SET )
    {
        if(txrate > ST25R3916_BR_6780)
        {
            return ERR_PARAM;
        }
        
        reg = (uint8_t)(reg & ~ST25R3916_REG_BIT_RATE_txrate_mask);     /* MISRA 10.3 */
        reg |= txrate<<ST25R3916_REG_BIT_RATE_txrate_shift;

    }
    return st25r3916WriteRegister( ST25R3916_REG_BIT_RATE, reg );    
}


/*******************************************************************************/
ReturnCode st25r3916PerformCollisionAvoidance( uint8_t FieldONCmd, uint8_t pdThreshold, uint8_t caThreshold, uint8_t nTRFW )
{
    uint8_t    treMask;
    uint32_t   irqs;
    ReturnCode err;
    
    if( (FieldONCmd != ST25R3916_CMD_INITIAL_RF_COLLISION) && (FieldONCmd != ST25R3916_CMD_RESPONSE_RF_COLLISION_N) )
    {
        return ERR_PARAM;
    }
    
    err = ERR_INTERNAL;
    
    
    /* Check if new thresholds are to be applied */
    if( (pdThreshold != ST25R3916_THRESHOLD_DO_NOT_SET) || (caThreshold != ST25R3916_THRESHOLD_DO_NOT_SET) )
    {
        treMask = 0;
        
        if(pdThreshold != ST25R3916_THRESHOLD_DO_NOT_SET)
        {
            treMask |= ST25R3916_REG_FIELD_THRESHOLD_ACTV_trg_mask;
        }
        
        if(caThreshold != ST25R3916_THRESHOLD_DO_NOT_SET)
        {
            treMask |= ST25R3916_REG_FIELD_THRESHOLD_ACTV_rfe_mask;
        }
            
        /* Set Detection Threshold and|or Collision Avoidance Threshold */
        st25r3916ChangeRegisterBits( ST25R3916_REG_FIELD_THRESHOLD_ACTV, treMask, (pdThreshold & ST25R3916_REG_FIELD_THRESHOLD_ACTV_trg_mask) | (caThreshold & ST25R3916_REG_FIELD_THRESHOLD_ACTV_rfe_mask ) );
    }
    
    /* Set n x TRFW */
    st25r3916ChangeRegisterBits( ST25R3916_REG_AUX, ST25R3916_REG_AUX_nfc_n_mask, nTRFW );
        
    /*******************************************************************************/
    /* Enable and clear CA specific interrupts and execute command */
    st25r3916GetInterrupt( (ST25R3916_IRQ_MASK_CAC | ST25R3916_IRQ_MASK_CAT | ST25R3916_IRQ_MASK_APON) );
    st25r3916EnableInterrupts( (ST25R3916_IRQ_MASK_CAC | ST25R3916_IRQ_MASK_CAT | ST25R3916_IRQ_MASK_APON) );
    
    st25r3916ExecuteCommand( FieldONCmd );
    
    /*******************************************************************************/
    /* Wait for initial APON interrupt, indicating anticollision avoidance done and ST25R3916's 
     * field is now on, or a CAC indicating a collision */   
    irqs = st25r3916WaitForInterruptsTimed( ( ST25R3916_IRQ_MASK_CAC | ST25R3916_IRQ_MASK_APON ), ST25R3916_TOUT_CA );    
   
    if( (ST25R3916_IRQ_MASK_CAC & irqs) != 0U )        /* Collision occurred */
    {        
        err = ERR_RF_COLLISION;
    }
    else if( (ST25R3916_IRQ_MASK_APON & irqs) != 0U )
    {
        /* After APON wait for CAT interrupt, indication field was switched on minimum guard time has been fulfilled */            
        irqs = st25r3916WaitForInterruptsTimed( ( ST25R3916_IRQ_MASK_CAT ), ST25R3916_TOUT_CA );        
                
        if( (ST25R3916_IRQ_MASK_CAT & irqs) != 0U )                             /* No Collision detected, Field On */
        {
            err = ERR_NONE;
        }
    }
    else
    {
        /* MISRA 15.7 - Empty else */
    }

    /* Clear any previous External Field events and disable CA specific interrupts */
    st25r3916GetInterrupt( (ST25R3916_IRQ_MASK_EOF | ST25R3916_IRQ_MASK_EON) );
    st25r3916DisableInterrupts( (ST25R3916_IRQ_MASK_CAC | ST25R3916_IRQ_MASK_CAT | ST25R3916_IRQ_MASK_APON) );
    
    return err;
}


/*******************************************************************************/
void st25r3916SetNumTxBits( uint16_t nBits )
{
    st25r3916WriteRegister( ST25R3916_REG_NUM_TX_BYTES2, (uint8_t)((nBits >> 0) & 0xFFU) );
    st25r3916WriteRegister( ST25R3916_REG_NUM_TX_BYTES1, (uint8_t)((nBits >> 8) & 0xFFU) );
}


/*******************************************************************************/
uint16_t st25r3916GetNumFIFOBytes( void )
{
    uint8_t  reg;
    uint16_t result;
    
    
    st25r3916ReadRegister( ST25R3916_REG_FIFO_STATUS2, &reg );
    reg    = ((reg & ST25R3916_REG_FIFO_STATUS2_fifo_b_mask) >> ST25R3916_REG_FIFO_STATUS2_fifo_b_shift);
    result = ((uint16_t)reg << 8);
    
    st25r3916ReadRegister( ST25R3916_REG_FIFO_STATUS1, &reg );
    result |= (((uint16_t)reg) & 0x00FFU);

    return result;
}


/*******************************************************************************/
uint8_t st25r3916GetNumFIFOLastBits( void )
{
    uint8_t  reg;
    
    st25r3916ReadRegister( ST25R3916_REG_FIFO_STATUS2, &reg );
    
    return ((reg & ST25R3916_REG_FIFO_STATUS2_fifo_lb_mask) >> ST25R3916_REG_FIFO_STATUS2_fifo_lb_shift);
}


/*******************************************************************************/
uint32_t st25r3916GetNoResponseTime( void )
{
    return gST25R3916NRT_64fcs;
}


/*******************************************************************************/
ReturnCode st25r3916SetNoResponseTime( uint32_t nrt_64fcs )
{    
    ReturnCode err;
    uint8_t    nrt_step;    
    uint32_t   tmpNRT;

    tmpNRT = nrt_64fcs;       /* MISRA 17.8 */
    err    = ERR_NONE;
    
    gST25R3916NRT_64fcs = tmpNRT;                                      /* Store given NRT value in 64/fc into local var       */
    nrt_step = ST25R3916_REG_TIMER_EMV_CONTROL_nrt_step_64fc;          /* Set default NRT in steps of 64/fc                   */
    
    
    if( tmpNRT > ST25R3916_NRT_MAX )                                   /* Check if the given NRT value fits using 64/fc steps */
    {
        nrt_step  = ST25R3916_REG_TIMER_EMV_CONTROL_nrt_step_4096_fc;  /* If not, change NRT set to 4096/fc                   */
        tmpNRT = ((tmpNRT + 63U) / 64U);                               /* Calculate number of steps in 4096/fc                */
        
        if( tmpNRT > ST25R3916_NRT_MAX )                               /* Check if the NRT value fits using 64/fc steps       */
        {
            tmpNRT = ST25R3916_NRT_MAX;                                /* Assign the maximum possible                         */
            err = ERR_PARAM;                                           /* Signal parameter error                              */
        }
        gST25R3916NRT_64fcs = (64U * tmpNRT);
    }

    /* Set the ST25R3916 NRT step units and the value */
    st25r3916ChangeRegisterBits( ST25R3916_REG_TIMER_EMV_CONTROL, ST25R3916_REG_TIMER_EMV_CONTROL_nrt_step, nrt_step );
    st25r3916WriteRegister( ST25R3916_REG_NO_RESPONSE_TIMER1, (uint8_t)(tmpNRT >> 8U) );
    st25r3916WriteRegister( ST25R3916_REG_NO_RESPONSE_TIMER2, (uint8_t)(tmpNRT & 0xFFU) );

    return err;
}


/*******************************************************************************/
ReturnCode st25r3916SetStartNoResponseTimer( uint32_t nrt_64fcs )
{
    ReturnCode err;
    
    err = st25r3916SetNoResponseTime( nrt_64fcs );
    if(err == ERR_NONE)
    {
        st25r3916ExecuteCommand( ST25R3916_CMD_START_NO_RESPONSE_TIMER );
    }
    
    return err;
}


/*******************************************************************************/
void st25r3916SetGPTime( uint16_t gpt_8fcs )
{
    st25r3916WriteRegister( ST25R3916_REG_GPT1, (uint8_t)(gpt_8fcs >> 8) );
    st25r3916WriteRegister( ST25R3916_REG_GPT2, (uint8_t)(gpt_8fcs & 0xFFU) );
}


/*******************************************************************************/
ReturnCode st25r3916SetStartGPTimer( uint16_t gpt_8fcs, uint8_t trigger_source )
{
    st25r3916SetGPTime( gpt_8fcs );
    st25r3916ChangeRegisterBits( ST25R3916_REG_TIMER_EMV_CONTROL, ST25R3916_REG_TIMER_EMV_CONTROL_gptc_mask, trigger_source );
    
    /* If there's no trigger source, start GPT immediately */
    if( trigger_source == ST25R3916_REG_TIMER_EMV_CONTROL_gptc_no_trigger )
    {
        st25r3916ExecuteCommand( ST25R3916_CMD_START_GP_TIMER );
    }

    return ERR_NONE;
}


/*******************************************************************************/
bool st25r3916CheckChipID( uint8_t *rev )
{
    uint8_t ID;
    
    ID = 0;    
    st25r3916ReadRegister( ST25R3916_REG_IC_IDENTITY, &ID );
    
    /* Check if IC Identity Register contains ST25R3916's IC type code */
    if( (ID & ST25R3916_REG_IC_IDENTITY_ic_type_mask) != ST25R3916_REG_IC_IDENTITY_ic_type_st25r3916 )
    {
        return false;
    }
        
    if(rev != NULL)
    {
        *rev = (ID & ST25R3916_REG_IC_IDENTITY_ic_rev_mask);
    }
    
    return true;
}


/*******************************************************************************/
ReturnCode st25r3916GetRegsDump( t_st25r3916Regs* regDump )
{
    uint8_t regIt;
    
    if(regDump == NULL)
    {
        return ERR_PARAM;
    }
    
    /* Dump Registers on space A */
    for( regIt = ST25R3916_REG_IO_CONF1; regIt <= ST25R3916_REG_IC_IDENTITY; regIt++ )
    {
        st25r3916ReadRegister(regIt, &regDump->RsA[regIt] );
    }
    
    regIt = 0;
    
    /* Read non-consecutive Registers on space B */
    st25r3916ReadRegister( ST25R3916_REG_EMD_SUP_CONF,      &regDump->RsB[regIt++] );
    st25r3916ReadRegister( ST25R3916_REG_SUBC_START_TIME,   &regDump->RsB[regIt++] );
    st25r3916ReadRegister( ST25R3916_REG_P2P_RX_CONF,       &regDump->RsB[regIt++] );
    st25r3916ReadRegister( ST25R3916_REG_CORR_CONF1,        &regDump->RsB[regIt++] );
    st25r3916ReadRegister( ST25R3916_REG_CORR_CONF2,        &regDump->RsB[regIt++] );
    st25r3916ReadRegister( ST25R3916_REG_SQUELCH_TIMER,     &regDump->RsB[regIt++] );
    st25r3916ReadRegister( ST25R3916_REG_FIELD_ON_GT,       &regDump->RsB[regIt++] );
    st25r3916ReadRegister( ST25R3916_REG_AUX_MOD,           &regDump->RsB[regIt++] );
    st25r3916ReadRegister( ST25R3916_REG_TX_DRIVER_TIMING,  &regDump->RsB[regIt++] );
    st25r3916ReadRegister( ST25R3916_REG_RES_AM_MOD,        &regDump->RsB[regIt++] );
    st25r3916ReadRegister( ST25R3916_REG_TX_DRIVER_STATUS,  &regDump->RsB[regIt++] );
    st25r3916ReadRegister( ST25R3916_REG_REGULATOR_RESULT,  &regDump->RsB[regIt++] );
    st25r3916ReadRegister( ST25R3916_REG_OVERSHOOT_CONF1,   &regDump->RsB[regIt++] );
    st25r3916ReadRegister( ST25R3916_REG_OVERSHOOT_CONF2,   &regDump->RsB[regIt++] );
    st25r3916ReadRegister( ST25R3916_REG_UNDERSHOOT_CONF1,  &regDump->RsB[regIt++] );
    st25r3916ReadRegister( ST25R3916_REG_UNDERSHOOT_CONF2,  &regDump->RsB[regIt++] );

    return ERR_NONE;
}


/*******************************************************************************/
bool st25r3916IsCmdValid( uint8_t cmd )
{
    if( !((cmd >= ST25R3916_CMD_SET_DEFAULT)             && (cmd <= ST25R3916_CMD_RESPONSE_RF_COLLISION_N))   && 
        !((cmd >= ST25R3916_CMD_GOTO_SENSE)              && (cmd <= ST25R3916_CMD_GOTO_SLEEP))                &&
        !((cmd >= ST25R3916_CMD_MASK_RECEIVE_DATA)       && (cmd <= ST25R3916_CMD_MEASURE_AMPLITUDE))         &&
        !((cmd >= ST25R3916_CMD_RESET_RXGAIN)            && (cmd <= ST25R3916_CMD_ADJUST_REGULATORS))         &&
        !((cmd >= ST25R3916_CMD_CALIBRATE_DRIVER_TIMING) && (cmd <= ST25R3916_CMD_START_PPON2_TIMER))         &&
         (cmd != ST25R3916_CMD_SPACE_B_ACCESS)           && (cmd != ST25R3916_CMD_STOP_NRT)                      )
    {
        return false;
    }
    return true;
}


/*******************************************************************************/
ReturnCode st25r3916StreamConfigure(const struct st25r3916StreamConfig *config)
{
    uint8_t smd;
    uint8_t mode;

    smd = 0;
    
    if( config->useBPSK != 0U )
    {
        mode = ST25R3916_REG_MODE_om_bpsk_stream;
        if( (config->din<2U) || (config->din>4U) ) /* not in fc/4 .. fc/16 */
        {
            return ERR_PARAM;
        }
        smd |= ((4U - config->din) << ST25R3916_REG_STREAM_MODE_scf_shift);
    }
    else
    {
        mode = ST25R3916_REG_MODE_om_subcarrier_stream;
        if( (config->din<3U) || (config->din>6U) ) /* not in fc/8 .. fc/64 */
        {
            return ERR_PARAM;
        }
        smd |= ((6U - config->din) << ST25R3916_REG_STREAM_MODE_scf_shift);
        if( config->report_period_length == 0U )
        {
            return ERR_PARAM;
        }
    }

    if( (config->dout<1U) || (config->dout>7U) ) /* not in fc/2 .. fc/128 */
    {
        return ERR_PARAM;
    }
    smd |= (7U - config->dout) << ST25R3916_REG_STREAM_MODE_stx_shift;

    if( config->report_period_length > 3U )
    {
        return ERR_PARAM;
    }
    smd |= (config->report_period_length << ST25R3916_REG_STREAM_MODE_scp_shift);

    st25r3916WriteRegister(ST25R3916_REG_STREAM_MODE, smd);
    st25r3916ChangeRegisterBits(ST25R3916_REG_MODE, ST25R3916_REG_MODE_om_mask, mode);

    return ERR_NONE;
}


/*******************************************************************************/
ReturnCode st25r3916GetRSSI( uint16_t *amRssi, uint16_t *pmRssi )
{
    /*******************************************************************************/
    /* MISRA 8.9 An object should be defined at block scope if its identifier only appears in a single function */
    /*< ST25R3916  RSSI Display Reg values:      0   1   2   3   4   5   6    7    8   9    a     b    c    d  e  f */
    static const uint16_t st25r3916Rssi2mV[] = { 0 ,20 ,27 ,37 ,52 ,72 ,99 ,136 ,190 ,262 ,357 ,500 ,686 ,950, 1150, 1150 };

    /* ST25R3916 2/3 stage gain reduction [dB]          0    0    0    0    0    3    6    9   12   15   18  na na na na na */
    static const uint16_t st25r3916Gain2Percent[] = { 100, 100, 100, 100, 100, 141, 200, 281, 398, 562, 794, 1, 1, 1, 1, 1 };
    /*******************************************************************************/

    uint8_t  rssi;
    uint8_t  gainRed;
    
    st25r3916ReadRegister( ST25R3916_REG_RSSI_RESULT, &rssi );
    st25r3916ReadRegister( ST25R3916_REG_GAIN_RED_STATE, &gainRed );
    
    if( amRssi != NULL )
    {
        *amRssi = (uint16_t) ( ( (uint32_t)st25r3916Rssi2mV[ (rssi >> ST25R3916_REG_RSSI_RESULT_rssi_am_shift) ] * (uint32_t)st25r3916Gain2Percent[ (gainRed >> ST25R3916_REG_GAIN_RED_STATE_gs_am_shift) ] ) / 100U );
    }
    
    if( pmRssi != NULL )
    {
        *pmRssi = (uint16_t) ( ( (uint32_t)st25r3916Rssi2mV[ (rssi & ST25R3916_REG_RSSI_RESULT_rssi_pm_mask) ] * (uint32_t)st25r3916Gain2Percent[ (gainRed & ST25R3916_REG_GAIN_RED_STATE_gs_pm_mask) ] ) / 100U );
    }
    
    return ERR_NONE;
}