hoverboard-firmware-hack-foc-serial-esc/Src/util.c

/**
  * This file is part of the hoverboard-firmware-hack project.
  *
  * Copyright (C) 2020-2021 Emanuel FERU <aerdronix@gmail.com>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation, either version 3 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

// Includes
#include <stdlib.h> // for abs()
#include <string.h>
#include "stm32f1xx_hal.h"
#include "defines.h"
#include "setup.h"
#include "config.h"
#include "comms.h"
#include "eeprom.h"
#include "util.h"
#include "BLDC_controller.h"
#include "rtwtypes.h"

#if defined(DEBUG_I2C_LCD) || defined(SUPPORT_LCD)
#include "hd44780.h"
#endif

/* =========================== Variable Definitions =========================== */

//------------------------------------------------------------------------
// Global variables set externally
//------------------------------------------------------------------------
extern volatile adc_buf_t adc_buffer;
extern I2C_HandleTypeDef hi2c2;
extern UART_HandleTypeDef huart2;
extern UART_HandleTypeDef huart3;

extern int16_t batVoltage;
extern uint8_t backwardDrive;
extern uint8_t buzzerFreq;              // global variable for the buzzer pitch. can be 1, 2, 3, 4, 5, 6, 7...
extern uint8_t buzzerPattern;           // global variable for the buzzer pattern. can be 1, 2, 3, 4, 5, 6, 7...

extern uint8_t enable;                  // global variable for motor enable

extern uint8_t nunchuk_data[6];
extern volatile uint32_t timeout;       // global variable for timeout
extern volatile uint32_t main_loop_counter;

#if defined(CONTROL_PPM_LEFT) || defined(CONTROL_PPM_RIGHT)
extern volatile uint16_t ppm_captured_value[PPM_NUM_CHANNELS+1];
#endif

#if defined(CONTROL_PWM_LEFT) || defined(CONTROL_PWM_RIGHT)
extern volatile uint16_t pwm_captured_ch1_value;
extern volatile uint16_t pwm_captured_ch2_value;
#endif

#ifdef BUTTONS_RIGHT
extern volatile uint8_t btn1;  // Blue
extern volatile uint8_t btn2;  // Green
#endif


//------------------------------------------------------------------------
// Global variables set here in util.c
//------------------------------------------------------------------------
// Matlab defines - from auto-code generation
//---------------
RT_MODEL rtM_Left_;                     /* Real-time model */
RT_MODEL rtM_Right_;                    /* Real-time model */
RT_MODEL *const rtM_Left  = &rtM_Left_;
RT_MODEL *const rtM_Right = &rtM_Right_;

extern P rtP_Left;                      /* Block parameters (auto storage) */
DW       rtDW_Left;                     /* Observable states */
ExtU     rtU_Left;                      /* External inputs */
ExtY     rtY_Left;                      /* External outputs */

P        rtP_Right;                     /* Block parameters (auto storage) */
DW       rtDW_Right;                    /* Observable states */
ExtU     rtU_Right;                     /* External inputs */
ExtY     rtY_Right;                     /* External outputs */
//---------------

int16_t  cmd1;                          // normalized input value. -1000 to 1000
int16_t  cmd2;                          // normalized input value. -1000 to 1000

int16_t  speedAvg;                      // average measured speed
int16_t  speedAvgAbs;                   // average measured speed in absolute
uint8_t  timeoutFlagADC    = 0;         // Timeout Flag for ADC Protection:    0 = OK, 1 = Problem detected (line disconnected or wrong ADC data)
uint8_t  timeoutFlagSerial = 0;         // Timeout Flag for Rx Serial command: 0 = OK, 1 = Problem detected (line disconnected or wrong Rx data)

uint8_t  ctrlModReqRaw = CTRL_MOD_REQ;
uint8_t  ctrlModReq    = CTRL_MOD_REQ;  // Final control mode request 

#if defined(DEBUG_I2C_LCD) || defined(SUPPORT_LCD)
LCD_PCF8574_HandleTypeDef lcd;
#endif

#if defined(CONTROL_NUNCHUK) || defined(SUPPORT_NUNCHUK)
uint8_t nunchuk_connected = 1;
#else
uint8_t nunchuk_connected = 0;
#endif

#ifdef VARIANT_TRANSPOTTER
float    setDistance;
uint16_t VirtAddVarTab[NB_OF_VAR] = {0x1337};     // Virtual address defined by the user: 0xFFFF value is prohibited
static   uint16_t saveValue       = 0;
static   uint8_t  saveValue_valid = 0;
#elif defined(CONTROL_ADC)
uint16_t VirtAddVarTab[NB_OF_VAR] = {0x1300, 1301, 1302, 1303, 1304, 1305, 1306, 1307, 1308};
#else
uint16_t VirtAddVarTab[NB_OF_VAR] = {0x1300};     // Dummy virtual address to avoid warnings
#endif


//------------------------------------------------------------------------
// Local variables
//------------------------------------------------------------------------
static int16_t INPUT_MAX;             // [-] Input target maximum limitation
static int16_t INPUT_MIN;             // [-] Input target minimum limitation

#ifdef CONTROL_ADC
  static uint8_t  cur_spd_valid = 0;
  static uint8_t  adc_cal_valid = 0;
  static uint16_t ADC1_MIN_CAL = ADC1_MIN;
  static uint16_t ADC1_MAX_CAL = ADC1_MAX;
  static uint16_t ADC2_MIN_CAL = ADC2_MIN;
  static uint16_t ADC2_MAX_CAL = ADC2_MAX;
  #ifdef ADC1_MID_POT
  static uint16_t ADC1_MID_CAL = ADC1_MID;
  #else
  static uint16_t ADC1_MID_CAL = 0;
  #endif
  #ifdef ADC1_MID_POT
  static uint16_t ADC2_MID_CAL = ADC2_MID;
  #else
  static uint16_t ADC2_MID_CAL = 0;
  #endif
#endif

#if defined(CONTROL_ADC) && defined(ADC_PROTECT_ENA)
static int16_t timeoutCntADC   = 0;  // Timeout counter for ADC Protection
#endif

#if defined(DEBUG_SERIAL_USART2) || defined(CONTROL_SERIAL_USART2) || defined(SIDEBOARD_SERIAL_USART2)
static uint8_t rx_buffer_L[SERIAL_BUFFER_SIZE];	// USART Rx DMA circular buffer
static uint32_t rx_buffer_L_len = ARRAY_LEN(rx_buffer_L);
#endif
#if defined(CONTROL_SERIAL_USART2) || defined(SIDEBOARD_SERIAL_USART2)
static uint16_t timeoutCntSerial_L  = 0;  		// Timeout counter for Rx Serial command
static uint8_t  timeoutFlagSerial_L = 0;  		// Timeout Flag for Rx Serial command: 0 = OK, 1 = Problem detected (line disconnected or wrong Rx data)
#endif
#if defined(SIDEBOARD_SERIAL_USART2)
SerialSideboard Sideboard_L;
SerialSideboard Sideboard_L_raw;
static uint32_t Sideboard_L_len = sizeof(Sideboard_L);
#endif

#if defined(DEBUG_SERIAL_USART3) || defined(CONTROL_SERIAL_USART3) || defined(SIDEBOARD_SERIAL_USART3)
static uint8_t rx_buffer_R[SERIAL_BUFFER_SIZE]; // USART Rx DMA circular buffer
static uint32_t rx_buffer_R_len = ARRAY_LEN(rx_buffer_R);
#endif
#if defined(CONTROL_SERIAL_USART3) || defined(SIDEBOARD_SERIAL_USART3)
static uint16_t timeoutCntSerial_R  = 0;  		// Timeout counter for Rx Serial command
static uint8_t  timeoutFlagSerial_R = 0;  		// Timeout Flag for Rx Serial command: 0 = OK, 1 = Problem detected (line disconnected or wrong Rx data)
#endif
#if defined(SIDEBOARD_SERIAL_USART3)
SerialSideboard Sideboard_R;
SerialSideboard Sideboard_R_raw;
static uint32_t Sideboard_R_len = sizeof(Sideboard_R);
#endif

#if defined(CONTROL_SERIAL_USART2) || defined(CONTROL_SERIAL_USART3)
static SerialCommand command;
static SerialCommand command_raw;
static uint32_t command_len = sizeof(command);
  #ifdef CONTROL_IBUS
  static uint16_t ibus_chksum;
  static uint16_t ibus_captured_value[IBUS_NUM_CHANNELS];
  #endif
#endif

#if !defined(VARIANT_HOVERBOARD) && (defined(SIDEBOARD_SERIAL_USART2) || defined(SIDEBOARD_SERIAL_USART3))
static uint8_t  sensor1_prev;           // holds the previous sensor1 state
static uint8_t  sensor2_prev;           // holds the previous sensor2 state
static uint8_t  sensor1_index;          // holds the press index number for sensor1, when used as a button
static uint8_t  sensor2_index;          // holds the press index number for sensor2, when used as a button
#endif

#if defined(SUPPORT_BUTTONS) || defined(SUPPORT_BUTTONS_LEFT) || defined(SUPPORT_BUTTONS_RIGHT)
static uint8_t button1, button2;
#endif

#ifdef VARIANT_HOVERCAR
static uint8_t brakePressed;
#endif


/* =========================== Initialization Functions =========================== */

void BLDC_Init(void) {
  /* Set BLDC controller parameters */ 
  rtP_Left.b_selPhaABCurrMeas   = 1;            // Left motor measured current phases {Green, Blue} = {iA, iB} -> do NOT change
  rtP_Left.z_ctrlTypSel         = CTRL_TYP_SEL;
  rtP_Left.b_diagEna            = DIAG_ENA; 
  rtP_Left.i_max                = (I_MOT_MAX * A2BIT_CONV) << 4;        // fixdt(1,16,4)
  rtP_Left.n_max                = N_MOT_MAX << 4;                       // fixdt(1,16,4)
  rtP_Left.b_fieldWeakEna       = FIELD_WEAK_ENA; 
  rtP_Left.id_fieldWeakMax      = (FIELD_WEAK_MAX * A2BIT_CONV) << 4;   // fixdt(1,16,4)
  rtP_Left.a_phaAdvMax          = PHASE_ADV_MAX << 4;                   // fixdt(1,16,4)
  rtP_Left.r_fieldWeakHi        = FIELD_WEAK_HI << 4;                   // fixdt(1,16,4)
  rtP_Left.r_fieldWeakLo        = FIELD_WEAK_LO << 4;                   // fixdt(1,16,4)

  rtP_Right                     = rtP_Left;     // Copy the Left motor parameters to the Right motor parameters
  rtP_Right.b_selPhaABCurrMeas  = 0;            // Right motor measured current phases {Blue, Yellow} = {iB, iC} -> do NOT change

  /* Pack LEFT motor data into RTM */
  rtM_Left->defaultParam        = &rtP_Left;
  rtM_Left->dwork               = &rtDW_Left;
  rtM_Left->inputs              = &rtU_Left;
  rtM_Left->outputs             = &rtY_Left;

  /* Pack RIGHT motor data into RTM */
  rtM_Right->defaultParam       = &rtP_Right;
  rtM_Right->dwork              = &rtDW_Right;
  rtM_Right->inputs             = &rtU_Right;
  rtM_Right->outputs            = &rtY_Right;

  /* Initialize BLDC controllers */
  BLDC_controller_initialize(rtM_Left);
  BLDC_controller_initialize(rtM_Right);
}

void Input_Lim_Init(void) {     // Input Limitations - ! Do NOT touch !    
  if (rtP_Left.b_fieldWeakEna || rtP_Right.b_fieldWeakEna) {
    INPUT_MAX = MAX( 1000, FIELD_WEAK_HI);
    INPUT_MIN = MIN(-1000,-FIELD_WEAK_HI);
  } else {
    INPUT_MAX =  1000;
    INPUT_MIN = -1000;
  }
}

void Input_Init(void) {
  #if defined(CONTROL_PPM_LEFT) || defined(CONTROL_PPM_RIGHT)
    PPM_Init();
  #endif

 #if defined(CONTROL_PWM_LEFT) || defined(CONTROL_PWM_RIGHT)
    PWM_Init();
  #endif

  #ifdef CONTROL_NUNCHUK
    I2C_Init();
    Nunchuk_Init();
  #endif

  #if defined(DEBUG_SERIAL_USART2) || defined(CONTROL_SERIAL_USART2) || defined(FEEDBACK_SERIAL_USART2) || defined(SIDEBOARD_SERIAL_USART2)
    UART2_Init();
  #endif
  #if defined(DEBUG_SERIAL_USART3) || defined(CONTROL_SERIAL_USART3) || defined(FEEDBACK_SERIAL_USART3) || defined(SIDEBOARD_SERIAL_USART3)
    UART3_Init();
  #endif
  #if defined(DEBUG_SERIAL_USART2) || defined(CONTROL_SERIAL_USART2) || defined(SIDEBOARD_SERIAL_USART2)
    HAL_UART_Receive_DMA(&huart2, (uint8_t *)rx_buffer_L, sizeof(rx_buffer_L));
    UART_DisableRxErrors(&huart2);
  #endif
  #if defined(DEBUG_SERIAL_USART3) || defined(CONTROL_SERIAL_USART3) || defined(SIDEBOARD_SERIAL_USART3)
    HAL_UART_Receive_DMA(&huart3, (uint8_t *)rx_buffer_R, sizeof(rx_buffer_R));
    UART_DisableRxErrors(&huart3);
  #endif

  #ifdef CONTROL_ADC  

    uint16_t writeCheck, i_max, n_max;
    HAL_FLASH_Unlock();    
    EE_Init();            /* EEPROM Init */    
    EE_ReadVariable(VirtAddVarTab[0], &writeCheck);
    if (writeCheck == FLASH_WRITE_KEY) {
      EE_ReadVariable(VirtAddVarTab[1], &ADC1_MIN_CAL);
      EE_ReadVariable(VirtAddVarTab[2], &ADC1_MAX_CAL);
      EE_ReadVariable(VirtAddVarTab[3], &ADC1_MID_CAL);
      EE_ReadVariable(VirtAddVarTab[4], &ADC2_MIN_CAL);
      EE_ReadVariable(VirtAddVarTab[5], &ADC2_MAX_CAL);
      EE_ReadVariable(VirtAddVarTab[6], &ADC2_MID_CAL);
      EE_ReadVariable(VirtAddVarTab[7], &i_max);
      EE_ReadVariable(VirtAddVarTab[8], &n_max);
      rtP_Left.i_max  = i_max;
      rtP_Left.n_max  = n_max;
      rtP_Right.i_max = i_max;
      rtP_Right.n_max = n_max;
    }
    HAL_FLASH_Lock();

  #endif

  #ifdef VARIANT_TRANSPOTTER    
    enable = 1;
    
    HAL_FLASH_Unlock();    
    EE_Init();            /* EEPROM Init */
    EE_ReadVariable(VirtAddVarTab[0], &saveValue);
    HAL_FLASH_Lock();

    setDistance = saveValue / 1000.0;
    if (setDistance < 0.2) {
      setDistance = 1.0;
    }
  #endif

  #if defined(DEBUG_I2C_LCD) || defined(SUPPORT_LCD)
    I2C_Init();
    HAL_Delay(50);
    lcd.pcf8574.PCF_I2C_ADDRESS = 0x27;
    lcd.pcf8574.PCF_I2C_TIMEOUT = 5;
    lcd.pcf8574.i2c             = hi2c2;
    lcd.NUMBER_OF_LINES         = NUMBER_OF_LINES_2;
    lcd.type                    = TYPE0;

    if(LCD_Init(&lcd)!=LCD_OK) {
        // error occured
        //TODO while(1);
    }

    LCD_ClearDisplay(&lcd);
    HAL_Delay(5);
    LCD_SetLocation(&lcd, 0, 0);
    #ifdef VARIANT_TRANSPOTTER
      LCD_WriteString(&lcd, "TranspOtter V2.1");
    #else
      LCD_WriteString(&lcd, "Hover V2.0");
    #endif
    LCD_SetLocation(&lcd,  0, 1); LCD_WriteString(&lcd, "Initializing...");
  #endif

  #if defined(VARIANT_TRANSPOTTER) && defined(SUPPORT_LCD)
    LCD_ClearDisplay(&lcd);
    HAL_Delay(5);
    LCD_SetLocation(&lcd,  0, 1); LCD_WriteString(&lcd, "Bat:");
    LCD_SetLocation(&lcd,  8, 1); LCD_WriteString(&lcd, "V");
    LCD_SetLocation(&lcd, 15, 1); LCD_WriteString(&lcd, "A");
    LCD_SetLocation(&lcd,  0, 0); LCD_WriteString(&lcd, "Len:");
    LCD_SetLocation(&lcd,  8, 0); LCD_WriteString(&lcd, "m(");
    LCD_SetLocation(&lcd, 14, 0); LCD_WriteString(&lcd, "m)");
  #endif
}

/**
  * @brief  Disable Rx Errors detection interrupts on UART peripheral (since we do not want DMA to be stopped)
  *         The incorrect data will be filtered based on the START_FRAME and checksum.
  * @param  huart: UART handle.
  * @retval None
  */
#if defined(DEBUG_SERIAL_USART2) || defined(CONTROL_SERIAL_USART2) || defined(SIDEBOARD_SERIAL_USART2) || \
    defined(DEBUG_SERIAL_USART3) || defined(CONTROL_SERIAL_USART3) || defined(SIDEBOARD_SERIAL_USART3)
void UART_DisableRxErrors(UART_HandleTypeDef *huart)
{
  /* Disable PE (Parity Error) interrupts */
  CLEAR_BIT(huart->Instance->CR1, USART_CR1_PEIE);

  /* Disable EIE (Frame error, noise error, overrun error) interrupts */
  CLEAR_BIT(huart->Instance->CR3, USART_CR3_EIE);
}
#endif


/* =========================== General Functions =========================== */

void poweronMelody(void) {
	for (int i = 8; i >= 0; i--) {
		buzzerFreq = (uint8_t)i;
		HAL_Delay(100);
	}
	buzzerFreq = 0;
}

void shortBeep(uint8_t freq) {
    buzzerFreq = freq;
    HAL_Delay(100);
    buzzerFreq = 0;
}

void shortBeepMany(uint8_t cnt) {
    for(uint8_t i = 0; i < cnt; i++) {
      shortBeep(i + 5);
    }
}

void longBeep(uint8_t freq) {
    buzzerFreq = freq;
    HAL_Delay(500);
    buzzerFreq = 0;
}

void calcAvgSpeed(void) {
    // Calculate measured average speed. The minus sign (-) is because motors spin in opposite directions
    #if   !defined(INVERT_L_DIRECTION) && !defined(INVERT_R_DIRECTION)
      speedAvg    = ( rtY_Left.n_mot - rtY_Right.n_mot) / 2;
    #elif !defined(INVERT_L_DIRECTION) &&  defined(INVERT_R_DIRECTION)
      speedAvg    = ( rtY_Left.n_mot + rtY_Right.n_mot) / 2;
    #elif  defined(INVERT_L_DIRECTION) && !defined(INVERT_R_DIRECTION)
      speedAvg    = (-rtY_Left.n_mot - rtY_Right.n_mot) / 2;
    #elif  defined(INVERT_L_DIRECTION) &&  defined(INVERT_R_DIRECTION)
      speedAvg    = (-rtY_Left.n_mot + rtY_Right.n_mot) / 2;
    #endif

    // Handle the case when SPEED_COEFFICIENT sign is negative (which is when most significant bit is 1)
    if (SPEED_COEFFICIENT & (1 << 16)) {
      speedAvg    = -speedAvg;
    } 
    speedAvgAbs   = abs(speedAvg);
}

 /*
 * Auto-calibration of the ADC Limits
 * This function finds the Minimum, Maximum, and Middle for the ADC input
 * Procedure:
 * - press the power button for more than 5 sec and release after the beep sound
 * - move the potentiometers freely to the min and max limits repeatedly
 * - release potentiometers to the resting postion
 * - press the power button to confirm or wait for the 20 sec timeout
 */
void adcCalibLim(void) {
  if (speedAvgAbs > 5) {    // do not enter this mode if motors are spinning
    return;
  }
  #ifdef CONTROL_ADC
    consoleLog("ADC calibration started... ");
    
    // Inititalization: MIN = a high values, MAX = a low value,
    int32_t adc1_fixdt = adc_buffer.l_tx2 << 16;
    int32_t adc2_fixdt = adc_buffer.l_rx2 << 16;
    uint16_t adc_cal_timeout = 0;
    uint16_t ADC1_MIN_temp   = 4095;
    uint16_t ADC1_MID_temp   = 0;
    uint16_t ADC1_MAX_temp   = 0;
    uint16_t ADC2_MIN_temp   = 4095;
    uint16_t ADC2_MID_temp   = 0;
    uint16_t ADC2_MAX_temp   = 0;
    
    adc_cal_valid = 1;

    // Extract MIN, MAX and MID from ADC while the power button is not pressed
    while (!HAL_GPIO_ReadPin(BUTTON_PORT, BUTTON_PIN) && adc_cal_timeout < 4000) {   // 20 sec timeout
      filtLowPass32(adc_buffer.l_tx2, FILTER, &adc1_fixdt);
      filtLowPass32(adc_buffer.l_rx2, FILTER, &adc2_fixdt);
      ADC1_MID_temp = (uint16_t)CLAMP(adc1_fixdt >> 16, 0, 4095);                   // convert fixed-point to integer
      ADC2_MID_temp = (uint16_t)CLAMP(adc2_fixdt >> 16, 0, 4095);
      ADC1_MIN_temp = MIN(ADC1_MIN_temp, ADC1_MID_temp);
      ADC1_MAX_temp = MAX(ADC1_MAX_temp, ADC1_MID_temp);      
      ADC2_MIN_temp = MIN(ADC2_MIN_temp, ADC2_MID_temp);
      ADC2_MAX_temp = MAX(ADC2_MAX_temp, ADC2_MID_temp);      
      adc_cal_timeout++;
      HAL_Delay(5);
    }

    // ADC calibration checks 
    #ifdef ADC_PROTECT_ENA
    if ((ADC1_MIN_temp + 150 - ADC_PROTECT_THRESH) > 0 && (ADC1_MAX_temp - 150 + ADC_PROTECT_THRESH) < 4095 && 
        (ADC2_MIN_temp + 150 - ADC_PROTECT_THRESH) > 0 && (ADC2_MAX_temp - 150 + ADC_PROTECT_THRESH) < 4095) {
      adc_cal_valid = 1;
    } else {
      adc_cal_valid = 0;
      consoleLog("FAIL (ADC out-of-range protection not possible)\n");
    }
    #endif

    // Add final ADC margin to have exact 0 and MAX at the minimum and maximum ADC value
    if (adc_cal_valid && (ADC1_MAX_temp - ADC1_MIN_temp) > 500 && (ADC2_MAX_temp - ADC2_MIN_temp) > 500) {
      ADC1_MIN_CAL = ADC1_MIN_temp + 150;
      ADC1_MID_CAL = ADC1_MID_temp;
      ADC1_MAX_CAL = ADC1_MAX_temp - 150;    
      ADC2_MIN_CAL = ADC2_MIN_temp + 150;
      ADC2_MID_CAL = ADC2_MID_temp;
      ADC2_MAX_CAL = ADC2_MAX_temp - 150;      
      consoleLog("OK\n");
    } else {
      adc_cal_valid = 0;
      consoleLog("FAIL (Pots travel too short)\n");
    }

  #endif
}


 /*
 * Update Maximum Motor Current Limit (via ADC1) and Maximum Speed Limit (via ADC2)
 * Procedure:
 * - press the power button for more than 5 sec and immediatelly after the beep sound press one more time shortly
 * - move and hold the pots to a desired limit position for Current and Speed
 * - press the power button to confirm or wait for the 10 sec timeout
 */
void updateCurSpdLim(void) {
  if (speedAvgAbs > 5) {    // do not enter this mode if motors are spinning
    return;
  }
  #ifdef CONTROL_ADC
    consoleLog("Torque and Speed limits update started... ");

    int32_t adc1_fixdt = adc_buffer.l_tx2 << 16;
    int32_t adc2_fixdt = adc_buffer.l_rx2 << 16;
    uint16_t cur_spd_timeout = 0;
    uint16_t cur_factor;    // fixdt(0,16,16)
    uint16_t spd_factor;    // fixdt(0,16,16)

    // Wait for the power button press
    while (!HAL_GPIO_ReadPin(BUTTON_PORT, BUTTON_PIN) && cur_spd_timeout < 2000) {  // 10 sec timeout
      filtLowPass32(adc_buffer.l_tx2, FILTER, &adc1_fixdt);
      filtLowPass32(adc_buffer.l_rx2, FILTER, &adc2_fixdt);
      cur_spd_timeout++;
      HAL_Delay(5);      
    }

    // Calculate scaling factors
    cur_factor      = CLAMP((adc1_fixdt - (ADC1_MIN_CAL << 16)) / (ADC1_MAX_CAL - ADC1_MIN_CAL), 6553, 65535);    // ADC1, MIN_cur(10%) = 1.5 A 
    spd_factor      = CLAMP((adc2_fixdt - (ADC2_MIN_CAL << 16)) / (ADC2_MAX_CAL - ADC2_MIN_CAL), 3276, 65535);    // ADC2, MIN_spd(5%)  = 50 rpm

    // Update maximum limits
    rtP_Left.i_max  = (int16_t)((I_MOT_MAX * A2BIT_CONV * cur_factor) >> 12);    // fixdt(0,16,16) to fixdt(1,16,4)
    rtP_Left.n_max  = (int16_t)((N_MOT_MAX * spd_factor) >> 12);                 // fixdt(0,16,16) to fixdt(1,16,4)
    rtP_Right.i_max = rtP_Left.i_max;
    rtP_Right.n_max = rtP_Left.n_max;

    cur_spd_valid   = 1;
    consoleLog("OK\n");

  #endif
}

 /*
 * Save Configuration to Flash
 * This function makes sure data is not lost after power-off
 */
void saveConfig() {
  #ifdef VARIANT_TRANSPOTTER
    if (saveValue_valid) {
      HAL_FLASH_Unlock();
      EE_WriteVariable(VirtAddVarTab[0], saveValue);
      HAL_FLASH_Lock();
    }
  #endif
  #ifdef CONTROL_ADC
    if (adc_cal_valid || cur_spd_valid) {
      HAL_FLASH_Unlock();
      EE_WriteVariable(VirtAddVarTab[0], FLASH_WRITE_KEY);
      EE_WriteVariable(VirtAddVarTab[1], ADC1_MIN_CAL);
      EE_WriteVariable(VirtAddVarTab[2], ADC1_MAX_CAL);
      EE_WriteVariable(VirtAddVarTab[3], ADC1_MID_CAL);
      EE_WriteVariable(VirtAddVarTab[4], ADC2_MIN_CAL);
      EE_WriteVariable(VirtAddVarTab[5], ADC2_MAX_CAL);
      EE_WriteVariable(VirtAddVarTab[6], ADC2_MID_CAL);
      EE_WriteVariable(VirtAddVarTab[7], rtP_Left.i_max);
      EE_WriteVariable(VirtAddVarTab[8], rtP_Left.n_max);
      HAL_FLASH_Lock();
    }
  #endif 
}

 /*
 * Add Dead-band to a signal
 * This function realizes a dead-band around 0 and scales the input within a min and a max
 */
int addDeadBand(int16_t u, int16_t deadBand, int16_t min, int16_t max) {
#if defined(CONTROL_PPM_LEFT) || defined(CONTROL_PPM_RIGHT) || defined(CONTROL_PWM_LEFT) || defined(CONTROL_PWM_RIGHT)
  int outVal = 0;
  if(u > -deadBand && u < deadBand) {
    outVal = 0;
  } else if(u > 0) {
    outVal = (INPUT_MAX * CLAMP(u - deadBand, 0, max - deadBand)) / (max - deadBand);
  } else {
    outVal = (INPUT_MIN * CLAMP(u + deadBand, min + deadBand, 0)) / (min + deadBand);
  }
  return outVal;
#else
  return 0;
#endif
}



/* =========================== Poweroff Functions =========================== */

void poweroff(void) {
	buzzerPattern = 0;
	enable = 0;
	consoleLog("-- Motors disabled --\r\n");
	for (int i = 0; i < 8; i++) {
		buzzerFreq = (uint8_t)i;
		HAL_Delay(100);
	}
  saveConfig();
	HAL_GPIO_WritePin(OFF_PORT, OFF_PIN, GPIO_PIN_RESET);
	while(1) {}
}


void poweroffPressCheck(void) {
	#if defined(CONTROL_ADC)
    if(HAL_GPIO_ReadPin(BUTTON_PORT, BUTTON_PIN)) {
      enable = 0;
      uint16_t cnt_press = 0;
      while(HAL_GPIO_ReadPin(BUTTON_PORT, BUTTON_PIN)) {
        HAL_Delay(10);
        if (cnt_press++ == 5 * 100) { shortBeep(5); }          
      }
      if (cnt_press >= 5 * 100) {                         // Check if press is more than 5 sec
        HAL_Delay(300);        
        if (HAL_GPIO_ReadPin(BUTTON_PORT, BUTTON_PIN)) {  // Double press: Adjust Max Current, Max Speed
          while(HAL_GPIO_ReadPin(BUTTON_PORT, BUTTON_PIN)) { HAL_Delay(10); }  
          longBeep(8);
          updateCurSpdLim();
          shortBeep(5);
        } else {                                          // Long press: Calibrate ADC Limits
          longBeep(16); 
          adcCalibLim();
          shortBeep(5);
        }
      } else {                                            // Short press: power off
        poweroff();
      }
    }
  #elif defined(VARIANT_TRANSPOTTER)
    if(HAL_GPIO_ReadPin(BUTTON_PORT, BUTTON_PIN)) {
      enable = 0;
      while(HAL_GPIO_ReadPin(BUTTON_PORT, BUTTON_PIN)) { HAL_Delay(10); }
      shortBeep(5);
      HAL_Delay(300);
      if (HAL_GPIO_ReadPin(BUTTON_PORT, BUTTON_PIN)) {
        while(HAL_GPIO_ReadPin(BUTTON_PORT, BUTTON_PIN)) { HAL_Delay(10); }
        longBeep(5);
        HAL_Delay(350);
        poweroff();
      } else {
        setDistance += 0.25;
        if (setDistance > 2.6) {
          setDistance = 0.5;
        }
        shortBeep(setDistance / 0.25);
        saveValue = setDistance * 1000;
        saveValue_valid = 1;
      }
    }
  #else
    if (HAL_GPIO_ReadPin(BUTTON_PORT, BUTTON_PIN)) {
      enable = 0;                                             // disable motors
      while (HAL_GPIO_ReadPin(BUTTON_PORT, BUTTON_PIN)) {}    // wait until button is released
      poweroff();                                             // release power-latch
    }
  #endif
}



/* =========================== Read Command Function =========================== */

void readCommand(void) {

    #if defined(CONTROL_NUNCHUK) || defined(SUPPORT_NUNCHUK)
      if (nunchuk_connected != 0) {
        Nunchuk_Read();
        cmd1 = CLAMP((nunchuk_data[0] - 127) * 8, INPUT_MIN, INPUT_MAX); // x - axis. Nunchuk joystick readings range 30 - 230
        cmd2 = CLAMP((nunchuk_data[1] - 128) * 8, INPUT_MIN, INPUT_MAX); // y - axis
				
				#ifdef SUPPORT_BUTTONS
					button1 = (uint8_t)nunchuk_data[5] & 1;
					button2 = (uint8_t)(nunchuk_data[5] >> 1) & 1;
				#endif
      }
    #endif

    #if defined(CONTROL_PPM_LEFT) || defined(CONTROL_PPM_RIGHT)
      cmd1 = CLAMP(addDeadBand((ppm_captured_value[0] - 500) * 2, PPM_DEADBAND, PPM_CH1_MIN, PPM_CH1_MAX), INPUT_MIN, INPUT_MAX);
      cmd2 = CLAMP(addDeadBand((ppm_captured_value[1] - 500) * 2, PPM_DEADBAND, PPM_CH2_MIN, PPM_CH2_MAX), INPUT_MIN, INPUT_MAX);
			#ifdef SUPPORT_BUTTONS
				button1 = ppm_captured_value[5] > 500;
				button2 = 0;
      #elif defined(SUPPORT_BUTTONS_LEFT) || defined(SUPPORT_BUTTONS_RIGHT)
        button1 = !HAL_GPIO_ReadPin(BUTTON1_PORT, BUTTON1_PIN);
        button2 = !HAL_GPIO_ReadPin(BUTTON2_PORT, BUTTON2_PIN);
			#endif
      // float scale = ppm_captured_value[2] / 1000.0f;     // not used for now, uncomment if needed
    #endif

    #if defined(CONTROL_PWM_LEFT) || defined(CONTROL_PWM_RIGHT)
      cmd1 = CLAMP(addDeadBand((pwm_captured_ch1_value - 500) * 2, PWM_DEADBAND, PWM_CH1_MIN, PWM_CH1_MAX), INPUT_MIN, INPUT_MAX);
      cmd2 = CLAMP(addDeadBand((pwm_captured_ch2_value - 500) * 2, PWM_DEADBAND, PWM_CH2_MIN, PWM_CH2_MAX), INPUT_MIN, INPUT_MAX);
      #if defined(SUPPORT_BUTTONS_LEFT) || defined(SUPPORT_BUTTONS_RIGHT)
        button1 = !HAL_GPIO_ReadPin(BUTTON1_PORT, BUTTON1_PIN);
        button2 = !HAL_GPIO_ReadPin(BUTTON2_PORT, BUTTON2_PIN);
      #endif
    #endif

    #ifdef CONTROL_ADC
      // ADC values range: 0-4095, see ADC-calibration in config.h
      #ifdef ADC1_MID_POT
        cmd1 = CLAMP((adc_buffer.l_tx2 - ADC1_MID_CAL) * INPUT_MAX / (ADC1_MAX_CAL - ADC1_MID_CAL), 0, INPUT_MAX) 
              -CLAMP((ADC1_MID_CAL - adc_buffer.l_tx2) * INPUT_MAX / (ADC1_MID_CAL - ADC1_MIN_CAL), 0, INPUT_MAX);    // ADC1        
      #else
        cmd1 = CLAMP((adc_buffer.l_tx2 - ADC1_MIN_CAL) * INPUT_MAX / (ADC1_MAX_CAL - ADC1_MIN_CAL), 0, INPUT_MAX);    // ADC1
      #endif

      #ifdef ADC2_MID_POT
        cmd2 = CLAMP((adc_buffer.l_rx2 - ADC2_MID_CAL) * INPUT_MAX / (ADC2_MAX_CAL - ADC2_MID_CAL), 0, INPUT_MAX)  
              -CLAMP((ADC2_MID_CAL - adc_buffer.l_rx2) * INPUT_MAX / (ADC2_MID_CAL - ADC2_MIN_CAL), 0, INPUT_MAX);    // ADC2        
      #else
        cmd2 = CLAMP((adc_buffer.l_rx2 - ADC2_MIN_CAL) * INPUT_MAX / (ADC2_MAX_CAL - ADC2_MIN_CAL), 0, INPUT_MAX);    // ADC2
      #endif

      #ifdef ADC_PROTECT_ENA
        if (adc_buffer.l_tx2 >= (ADC1_MIN_CAL - ADC_PROTECT_THRESH) && adc_buffer.l_tx2 <= (ADC1_MAX_CAL + ADC_PROTECT_THRESH) && 
            adc_buffer.l_rx2 >= (ADC2_MIN_CAL - ADC_PROTECT_THRESH) && adc_buffer.l_rx2 <= (ADC2_MAX_CAL + ADC_PROTECT_THRESH)) {
          if (timeoutFlagADC) {                         // Check for previous timeout flag  
            if (timeoutCntADC-- <= 0)                   // Timeout de-qualification
              timeoutFlagADC  = 0;                      // Timeout flag cleared           
          } else {
            timeoutCntADC     = 0;                      // Reset the timeout counter         
          }
        } else {
          if (timeoutCntADC++ >= ADC_PROTECT_TIMEOUT) { // Timeout qualification
            timeoutFlagADC    = 1;                      // Timeout detected
            timeoutCntADC     = ADC_PROTECT_TIMEOUT;    // Limit timout counter value
          }
        }

        if (timeoutFlagADC) {                           // In case of timeout bring the system to a Safe State
          ctrlModReq  = 0;                              // OPEN_MODE request. This will bring the motor power to 0 in a controlled way
          cmd1        = 0;
          cmd2        = 0;
        } else {
          ctrlModReq  = ctrlModReqRaw;                  // Follow the Mode request
        }        
      #endif

      #if defined(SUPPORT_BUTTONS_LEFT) || defined(SUPPORT_BUTTONS_RIGHT)
        button1 = !HAL_GPIO_ReadPin(BUTTON1_PORT, BUTTON1_PIN);
        button2 = !HAL_GPIO_ReadPin(BUTTON2_PORT, BUTTON2_PIN);
      #endif
      timeout = 0;
    #endif

    #if defined(CONTROL_SERIAL_USART2) || defined(CONTROL_SERIAL_USART3)
        // Handle received data validity, timeout and fix out-of-sync if necessary
      #ifdef CONTROL_IBUS    
        for (uint8_t i = 0; i < (IBUS_NUM_CHANNELS * 2); i+=2) {
          ibus_captured_value[(i/2)] = CLAMP(command.channels[i] + (command.channels[i+1] << 8) - 1000, 0, INPUT_MAX); // 1000-2000 -> 0-1000
        }
        cmd1 = CLAMP((ibus_captured_value[0] - 500) * 2, INPUT_MIN, INPUT_MAX);
        cmd2 = CLAMP((ibus_captured_value[1] - 500) * 2, INPUT_MIN, INPUT_MAX); 
      #else
       if (IN_RANGE(command.steer, INPUT_MIN, INPUT_MAX) && IN_RANGE(command.speed, INPUT_MIN, INPUT_MAX)) {
        cmd1 = command.steer;
        cmd2 = command.speed;
       }
      #endif

      if (timeoutFlagSerial) {                          // In case of timeout bring the system to a Safe State
        ctrlModReq  = 0;                                // OPEN_MODE request. This will bring the motor power to 0 in a controlled way
        cmd1        = 0;
        cmd2        = 0;
      } else {
        ctrlModReq  = ctrlModReqRaw;                    // Follow the Mode request
      }

      #if defined(SUPPORT_BUTTONS_LEFT) || defined(SUPPORT_BUTTONS_RIGHT)
        button1 = !HAL_GPIO_ReadPin(BUTTON1_PORT, BUTTON1_PIN);
        button2 = !HAL_GPIO_ReadPin(BUTTON2_PORT, BUTTON2_PIN);
      #endif
      timeout = 0;
    #endif

    #if defined(CONTROL_SERIAL_USART2) || defined(SIDEBOARD_SERIAL_USART2)
      if (timeoutCntSerial_L++ >= SERIAL_TIMEOUT) {     // Timeout qualification
        timeoutFlagSerial_L = 1;                        // Timeout detected
        timeoutCntSerial_L  = SERIAL_TIMEOUT;           // Limit timout counter value
      }
      timeoutFlagSerial = timeoutFlagSerial_L;
    #endif
    #if defined(CONTROL_SERIAL_USART3) || defined(SIDEBOARD_SERIAL_USART3)
      if (timeoutCntSerial_R++ >= SERIAL_TIMEOUT) {     // Timeout qualification
        timeoutFlagSerial_R = 1;                        // Timeout detected
        timeoutCntSerial_R  = SERIAL_TIMEOUT;           // Limit timout counter value
      }
      timeoutFlagSerial = timeoutFlagSerial_R;
    #endif
    #if defined(SIDEBOARD_SERIAL_USART2) && defined(SIDEBOARD_SERIAL_USART3)
      timeoutFlagSerial = timeoutFlagSerial_L || timeoutFlagSerial_R;
    #endif

    #ifdef VARIANT_HOVERCAR      
        brakePressed = (uint8_t)(cmd1 > 50);
    #endif

    #ifdef VARIANT_TRANSPOTTER
      #ifdef GAMETRAK_CONNECTION_NORMAL
        cmd1 = adc_buffer.l_rx2;
        cmd2 = adc_buffer.l_tx2;
      #endif
      #ifdef GAMETRAK_CONNECTION_ALTERNATE
        cmd1 = adc_buffer.l_tx2;
        cmd2 = adc_buffer.l_rx2;
      #endif
    #endif

}


/*
 * Check for new data received on USART2 with DMA: refactored function from https://github.com/MaJerle/stm32-usart-uart-dma-rx-tx
 * - this function is called for every USART IDLE line detection, in the USART interrupt handler
 */
void usart2_rx_check(void)
{
  #if defined(DEBUG_SERIAL_USART2) || defined(CONTROL_SERIAL_USART2) || defined(SIDEBOARD_SERIAL_USART2)  
  static uint32_t old_pos;
  uint32_t pos;
  pos = rx_buffer_L_len - __HAL_DMA_GET_COUNTER(huart2.hdmarx);         // Calculate current position in buffer
  #endif

  #if defined(DEBUG_SERIAL_USART2)
  if (pos != old_pos) {                                                 // Check change in received data		
    if (pos > old_pos) {                                                // "Linear" buffer mode: check if current position is over previous one
      usart_process_debug(&rx_buffer_L[old_pos], pos - old_pos);        // Process data
    } else {                                                            // "Overflow" buffer mode
      usart_process_debug(&rx_buffer_L[old_pos], rx_buffer_L_len - old_pos); // First Process data from the end of buffer            
      if (pos > 0) {                                                    // Check and continue with beginning of buffer				
        usart_process_debug(&rx_buffer_L[0], pos);                      // Process remaining data 			
      }
    }
  }
	#endif // DEBUG_SERIAL_USART2

  #ifdef CONTROL_SERIAL_USART2
  uint8_t *ptr;	
  if (pos != old_pos) {                                                 // Check change in received data
    ptr = (uint8_t *)&command_raw;                                      // Initialize the pointer with command_raw address
    if (pos > old_pos && (pos - old_pos) == command_len) {              // "Linear" buffer mode: check if current position is over previous one AND data length equals expected length
      memcpy(ptr, &rx_buffer_L[old_pos], command_len);                  // Copy data. This is possible only if command_raw is contiguous! (meaning all the structure members have the same size)
      usart_process_command(&command_raw, &command, 2);                 // Process data
    } else if ((rx_buffer_L_len - old_pos + pos) == command_len) {      // "Overflow" buffer mode: check if data length equals expected length
      memcpy(ptr, &rx_buffer_L[old_pos], rx_buffer_L_len - old_pos);    // First copy data from the end of buffer
      if (pos > 0) {                                                    // Check and continue with beginning of buffer
        ptr += rx_buffer_L_len - old_pos;                               // Move to correct position in command_raw		
        memcpy(ptr, &rx_buffer_L[0], pos);                              // Copy remaining data
      }
      usart_process_command(&command_raw, &command, 2);                 // Process data
    }
  }
  #endif // CONTROL_SERIAL_USART2

	#ifdef SIDEBOARD_SERIAL_USART2
  uint8_t *ptr;	
  if (pos != old_pos) {                                                 // Check change in received data
    ptr = (uint8_t *)&Sideboard_L_raw;                                  // Initialize the pointer with Sideboard_raw address
    if (pos > old_pos && (pos - old_pos) == Sideboard_L_len) {          // "Linear" buffer mode: check if current position is over previous one AND data length equals expected length
      memcpy(ptr, &rx_buffer_L[old_pos], Sideboard_L_len);              // Copy data. This is possible only if Sideboard_raw is contiguous! (meaning all the structure members have the same size)
      usart_process_sideboard(&Sideboard_L_raw, &Sideboard_L, 2);       // Process data
    } else if ((rx_buffer_L_len - old_pos + pos) == Sideboard_L_len) {  // "Overflow" buffer mode: check if data length equals expected length
      memcpy(ptr, &rx_buffer_L[old_pos], rx_buffer_L_len - old_pos);    // First copy data from the end of buffer
      if (pos > 0) {                                                    // Check and continue with beginning of buffer
        ptr += rx_buffer_L_len - old_pos;                               // Move to correct position in Sideboard_raw		
        memcpy(ptr, &rx_buffer_L[0], pos);                              // Copy remaining data
      }
      usart_process_sideboard(&Sideboard_L_raw, &Sideboard_L, 2);       // Process data
    }
  }
  #endif // SIDEBOARD_SERIAL_USART2

  #if defined(DEBUG_SERIAL_USART2) || defined(CONTROL_SERIAL_USART2) || defined(SIDEBOARD_SERIAL_USART2)
  old_pos = pos;                                                        // Update old position
  if (old_pos == rx_buffer_L_len) {                                     // Check and manually update if we reached end of buffer
    old_pos = 0;
  }
	#endif
}


/*
 * Check for new data received on USART3 with DMA: refactored function from https://github.com/MaJerle/stm32-usart-uart-dma-rx-tx
 * - this function is called for every USART IDLE line detection, in the USART interrupt handler
 */
void usart3_rx_check(void)
{
  #if defined(DEBUG_SERIAL_USART3) || defined(CONTROL_SERIAL_USART3) || defined(SIDEBOARD_SERIAL_USART3)
  static uint32_t old_pos;
  uint32_t pos;  
  pos = rx_buffer_R_len - __HAL_DMA_GET_COUNTER(huart3.hdmarx);         // Calculate current position in buffer
  #endif

  #if defined(DEBUG_SERIAL_USART3)
  if (pos != old_pos) {                                                 // Check change in received data		
    if (pos > old_pos) {                                                // "Linear" buffer mode: check if current position is over previous one
      usart_process_debug(&rx_buffer_R[old_pos], pos - old_pos);        // Process data
    } else {                                                            // "Overflow" buffer mode
      usart_process_debug(&rx_buffer_R[old_pos], rx_buffer_R_len - old_pos); // First Process data from the end of buffer            
      if (pos > 0) {                                                    // Check and continue with beginning of buffer				
        usart_process_debug(&rx_buffer_R[0], pos);                      // Process remaining data 			
      }
    }
  }
	#endif // DEBUG_SERIAL_USART3

  #ifdef CONTROL_SERIAL_USART3
  uint8_t *ptr;	
  if (pos != old_pos) {                                                 // Check change in received data
    ptr = (uint8_t *)&command_raw;                                      // Initialize the pointer with command_raw address
    if (pos > old_pos && (pos - old_pos) == command_len) {              // "Linear" buffer mode: check if current position is over previous one AND data length equals expected length
      memcpy(ptr, &rx_buffer_R[old_pos], command_len);                  // Copy data. This is possible only if command_raw is contiguous! (meaning all the structure members have the same size)
      usart_process_command(&command_raw, &command, 3);                 // Process data
    } else if ((rx_buffer_R_len - old_pos + pos) == command_len) {      // "Overflow" buffer mode: check if data length equals expected length
      memcpy(ptr, &rx_buffer_R[old_pos], rx_buffer_R_len - old_pos);    // First copy data from the end of buffer
      if (pos > 0) {                                                    // Check and continue with beginning of buffer
        ptr += rx_buffer_R_len - old_pos;                               // Move to correct position in command_raw		
        memcpy(ptr, &rx_buffer_R[0], pos);                              // Copy remaining data
      }
      usart_process_command(&command_raw, &command, 3);                 // Process data
    }
  }
  #endif // CONTROL_SERIAL_USART3

	#ifdef SIDEBOARD_SERIAL_USART3
  uint8_t *ptr;
  if (pos != old_pos) {                                                 // Check change in received data
    ptr = (uint8_t *)&Sideboard_R_raw;                                  // Initialize the pointer with Sideboard_raw address
    if (pos > old_pos && (pos - old_pos) == Sideboard_R_len) {          // "Linear" buffer mode: check if current position is over previous one AND data length equals expected length
      memcpy(ptr, &rx_buffer_R[old_pos], Sideboard_R_len);              // Copy data. This is possible only if Sideboard_raw is contiguous! (meaning all the structure members have the same size)
      usart_process_sideboard(&Sideboard_R_raw, &Sideboard_R, 3);       // Process data
    } else if ((rx_buffer_R_len - old_pos + pos) == Sideboard_R_len) {  // "Overflow" buffer mode: check if data length equals expected length
      memcpy(ptr, &rx_buffer_R[old_pos], rx_buffer_R_len - old_pos);    // First copy data from the end of buffer
      if (pos > 0) {                                                    // Check and continue with beginning of buffer
        ptr += rx_buffer_R_len - old_pos;                               // Move to correct position in Sideboard_raw		
        memcpy(ptr, &rx_buffer_R[0], pos);                              // Copy remaining data
      }
      usart_process_sideboard(&Sideboard_R_raw, &Sideboard_R, 3);       // Process data
    }
  }
  #endif // SIDEBOARD_SERIAL_USART3

  #if defined(DEBUG_SERIAL_USART3) || defined(CONTROL_SERIAL_USART3) || defined(SIDEBOARD_SERIAL_USART3)
  old_pos = pos;                                                        // Update old position
  if (old_pos == rx_buffer_R_len) {                                     // Check and manually update if we reached end of buffer
    old_pos = 0;
  }
	#endif
}

/*
 * Process Rx debug user command input
 */
#if defined(DEBUG_SERIAL_USART2) || defined(DEBUG_SERIAL_USART3)
void usart_process_debug(uint8_t *userCommand, uint32_t len)
{
	for (; len > 0; len--, userCommand++) {
		if (*userCommand != '\n' && *userCommand != '\r') { 	// Do not accept 'new line' and 'carriage return' commands
      consoleLog("-- Command received --\r\n");						
			// handle_input(*userCommand);                      // -> Create this function to handle the user commands
		}
  }
}
#endif // SERIAL_DEBUG

/*
 * Process command Rx data
 * - if the command_in data is valid (correct START_FRAME and checksum) copy the command_in to command_out
 */
#if defined(CONTROL_SERIAL_USART2) || defined(CONTROL_SERIAL_USART3)
void usart_process_command(SerialCommand *command_in, SerialCommand *command_out, uint8_t usart_idx)
{
  #ifdef CONTROL_IBUS
    if (command_in->start == IBUS_LENGTH && command_in->type == IBUS_COMMAND) {
      ibus_chksum = 0xFFFF - IBUS_LENGTH - IBUS_COMMAND;
      for (uint8_t i = 0; i < (IBUS_NUM_CHANNELS * 2); i++) {
        ibus_chksum -= command_in->channels[i];
      }
      if (ibus_chksum == (uint16_t)((command_in->checksumh << 8) + command_in->checksuml)) {
        *command_out = *command_in;
        if (usart_idx == 2) {             // Sideboard USART2
          #ifdef CONTROL_SERIAL_USART2
          timeoutCntSerial_L  = 0;        // Reset timeout counter
          timeoutFlagSerial_L = 0;        // Clear timeout flag
          #endif
        } else if (usart_idx == 3) {      // Sideboard USART3
          #ifdef CONTROL_SERIAL_USART3
          timeoutCntSerial_R  = 0;        // Reset timeout counter
          timeoutFlagSerial_R = 0;        // Clear timeout flag
          #endif
        }
      }
    }
  #else
  uint16_t checksum;
	if (command_in->start == SERIAL_START_FRAME) {
		checksum = (uint16_t)(command_in->start ^ command_in->steer ^ command_in->speed);
		if (command_in->checksum == checksum) {					
			*command_out = *command_in;
      if (usart_idx == 2) {             // Sideboard USART2
        #ifdef CONTROL_SERIAL_USART2
        timeoutCntSerial_L  = 0;        // Reset timeout counter
        timeoutFlagSerial_L = 0;        // Clear timeout flag
        #endif
      } else if (usart_idx == 3) {      // Sideboard USART3
        #ifdef CONTROL_SERIAL_USART3
        timeoutCntSerial_R  = 0;        // Reset timeout counter
        timeoutFlagSerial_R = 0;        // Clear timeout flag
        #endif
      }
    }
  }
  #endif
}
#endif

/*
 * Process Sideboard Rx data
 * - if the Sideboard_in data is valid (correct START_FRAME and checksum) copy the Sideboard_in to Sideboard_out
 */
#if defined(SIDEBOARD_SERIAL_USART2) || defined(SIDEBOARD_SERIAL_USART3)
void usart_process_sideboard(SerialSideboard *Sideboard_in, SerialSideboard *Sideboard_out, uint8_t usart_idx)
{	
  uint16_t checksum;
	if (Sideboard_in->start == SERIAL_START_FRAME) {
		checksum = (uint16_t)(Sideboard_in->start ^ Sideboard_in->roll ^ Sideboard_in->pitch ^ Sideboard_in->yaw ^ Sideboard_in->sensors);
		if (Sideboard_in->checksum == checksum) {					
			*Sideboard_out = *Sideboard_in;
      if (usart_idx == 2) {             // Sideboard USART2
        #ifdef SIDEBOARD_SERIAL_USART2
        timeoutCntSerial_L  = 0;        // Reset timeout counter
        timeoutFlagSerial_L = 0;        // Clear timeout flag
        #endif
      } else if (usart_idx == 3) {      // Sideboard USART3
        #ifdef SIDEBOARD_SERIAL_USART3
        timeoutCntSerial_R  = 0;        // Reset timeout counter
        timeoutFlagSerial_R = 0;        // Clear timeout flag
        #endif
      }
    }
	}
}
#endif


/* =========================== Sideboard Functions =========================== */

/*
 * Sideboard LEDs Handling
 * This function manages the leds behavior connected to the sideboard
 */
void sideboardLeds(uint8_t *leds) {
  #if defined(SIDEBOARD_SERIAL_USART2) || defined(SIDEBOARD_SERIAL_USART3)
    // Enable flag: use LED4 (bottom Blue)
    // enable == 1, turn on led
    // enable == 0, blink led
    if (enable) {
      *leds |= LED4_SET;
    } else if (!enable && (main_loop_counter % 20 == 0)) {
      *leds ^= LED4_SET;
    }

    // Backward Drive: use LED5 (upper Blue)
    // backwardDrive == 1, blink led
    // backwardDrive == 0, turn off led
    if (backwardDrive && (main_loop_counter % 50 == 0)) {
      *leds ^= LED5_SET;
    }

    // Brake: use LED5 (upper Blue)
    // brakePressed == 1, turn on led
    // brakePressed == 0, turn off led
    #ifdef VARIANT_HOVERCAR
      if (brakePressed) {
        *leds |= LED5_SET;
      } else if (!brakePressed && !backwardDrive) {
        *leds &= ~LED5_SET;
      }
    #endif

    // Battery Level Indicator: use LED1, LED2, LED3
    if (main_loop_counter % BAT_BLINK_INTERVAL == 0) {              //  | RED (LED1) | YELLOW (LED3) | GREEN (LED2) |
      if (batVoltage < BAT_DEAD) {                                  //  |     0      |       0       |      0       |
        *leds &= ~LED1_SET & ~LED3_SET & ~LED2_SET;          
      } else if (batVoltage < BAT_LVL1) {                           //  |     B      |       0       |      0       |
        *leds ^= LED1_SET;
        *leds &= ~LED3_SET & ~LED2_SET;
      } else if (batVoltage < BAT_LVL2) {                           //  |     1      |       0       |      0       |
        *leds |= LED1_SET;
        *leds &= ~LED3_SET & ~LED2_SET;
      } else if (batVoltage < BAT_LVL3) {                           //  |     0      |       B       |      0       |
        *leds ^= LED3_SET;
        *leds &= ~LED1_SET & ~LED2_SET;
      } else if (batVoltage < BAT_LVL4) {                           //  |     0      |       1       |      0       |
        *leds |= LED3_SET;
        *leds &= ~LED1_SET & ~LED2_SET;
      } else if (batVoltage < BAT_LVL5) {                           //  |     0      |       0       |      B       |
        *leds ^= LED2_SET;
        *leds &= ~LED1_SET & ~LED3_SET;
      } else {                                                      //  |     0      |       0       |      1       |
        *leds |= LED2_SET;
        *leds &= ~LED1_SET & ~LED3_SET;
      }
    }

    // Error handling
    // Critical error:  LED1 on (RED)     + high pitch beep (hadled in main)
    // Soft error:      LED3 on (YELLOW)  + low  pitch beep (hadled in main)
    if (rtY_Left.z_errCode || rtY_Right.z_errCode) {
      *leds |= LED1_SET;
      *leds &= ~LED3_SET & ~LED2_SET;
    }
    if (timeoutFlagADC || timeoutFlagSerial) {
      *leds |= LED3_SET;
      *leds &= ~LED1_SET & ~LED2_SET;
    }
  #endif
}

/*
 * Sideboard Sensor Handling
 * This function manages the sideboards photo sensors.
 * In non-hoverboard variants, the sensors are used as push buttons.
 */
void sideboardSensors(uint8_t sensors) {
  #if !defined(VARIANT_HOVERBOARD) && (defined(SIDEBOARD_SERIAL_USART2) || defined(SIDEBOARD_SERIAL_USART3))
    uint8_t sensor1_rising_edge, sensor2_rising_edge;
    sensor1_rising_edge  = (sensors & SENSOR1_SET) && !sensor1_prev;
    sensor2_rising_edge  = (sensors & SENSOR2_SET) && !sensor2_prev;
    sensor1_prev         =  sensors & SENSOR1_SET;
    sensor2_prev         =  sensors & SENSOR2_SET;

    // Control MODE and Control Type Handling: use Sensor1 as push button
    if (sensor1_rising_edge) {
      sensor1_index++;
      if (sensor1_index > 4) { sensor1_index = 0; }
      switch (sensor1_index) {
        case 0:     // FOC VOLTAGE
          rtP_Left.z_ctrlTypSel  = 2;
          rtP_Right.z_ctrlTypSel = 2;
          ctrlModReqRaw          = 1;
          break;
        case 1:     // FOC SPEED
          ctrlModReqRaw          = 2;
          break;
        case 2:     // FOC TORQUE
          ctrlModReqRaw          = 3;
          break;
        case 3:     // SINUSOIDAL
          rtP_Left.z_ctrlTypSel  = 1;
          rtP_Right.z_ctrlTypSel = 1;
          break;
        case 4:     // COMMUTATION
          rtP_Left.z_ctrlTypSel  = 0;
          rtP_Right.z_ctrlTypSel = 0;
          break;    
      }
      shortBeepMany(sensor1_index + 1);
    }

    // Field Weakening: use Sensor2 as push button
    if (sensor2_rising_edge) {
      sensor2_index++;
      if (sensor2_index > 1) { sensor2_index = 0; }
      switch (sensor2_index) {
        case 0:     // FW Disabled
          rtP_Left.b_fieldWeakEna  = 0; 
          rtP_Right.b_fieldWeakEna = 0;
          Input_Lim_Init();
          break;
        case 1:     // FW Enabled
          rtP_Left.b_fieldWeakEna  = 1; 
          rtP_Right.b_fieldWeakEna = 1;
          Input_Lim_Init();
          break; 
      }
      shortBeepMany(sensor2_index + 1);            
    }
  #endif
}



/* =========================== Filtering Functions =========================== */

  /* Low pass filter fixed-point 32 bits: fixdt(1,32,16)
  * Max:  32767.99998474121
  * Min: -32768
  * Res:  1.52587890625e-05
  * 
  * Inputs:       u     = int16 or int32
  * Outputs:      y     = fixdt(1,32,16)
  * Parameters:   coef  = fixdt(0,16,16) = [0,65535U]
  * 
  * Example: 
  * If coef = 0.8 (in floating point), then coef = 0.8 * 2^16 = 52429 (in fixed-point)
  * filtLowPass16(u, 52429, &y);
  * yint = (int16_t)(y >> 16); // the integer output is the fixed-point ouput shifted by 16 bits
  */
 void filtLowPass32(int32_t u, uint16_t coef, int32_t *y) {
  int64_t tmp;  
  tmp = ((int64_t)((u << 4) - (*y >> 12)) * coef) >> 4;
  tmp = CLAMP(tmp, -2147483648LL, 2147483647LL);  // Overflow protection: 2147483647LL = 2^31 - 1
  *y = (int32_t)tmp + (*y);
}
  // Old filter
  // Inputs:       u     = int16
  // Outputs:      y     = fixdt(1,32,20)
  // Parameters:   coef  = fixdt(0,16,16) = [0,65535U]
  // yint = (int16_t)(y >> 20); // the integer output is the fixed-point ouput shifted by 20 bits
  // void filtLowPass32(int16_t u, uint16_t coef, int32_t *y) {
  //   int32_t tmp;  
  //   tmp = (int16_t)(u << 4) - (*y >> 16);  
  //   tmp = CLAMP(tmp, -32768, 32767);  // Overflow protection  
  //   *y  = coef * tmp + (*y);
  // }


  /* rateLimiter16(int16_t u, int16_t rate, int16_t *y);
  * Inputs:       u     = int16
  * Outputs:      y     = fixdt(1,16,4)
  * Parameters:   rate  = fixdt(1,16,4) = [0, 32767] Do NOT make rate negative (>32767)
  */
void rateLimiter16(int16_t u, int16_t rate, int16_t *y) {
  int16_t q0;
  int16_t q1;

  q0 = (u << 4)  - *y;

  if (q0 > rate) {
    q0 = rate;
  } else {
    q1 = -rate;
    if (q0 < q1) {
      q0 = q1;
    }
  }

  *y = q0 + *y;
}


  /* mixerFcn(rtu_speed, rtu_steer, &rty_speedR, &rty_speedL); 
  * Inputs:       rtu_speed, rtu_steer                  = fixdt(1,16,4)
  * Outputs:      rty_speedR, rty_speedL                = int16_t
  * Parameters:   SPEED_COEFFICIENT, STEER_COEFFICIENT  = fixdt(0,16,14)
  */
void mixerFcn(int16_t rtu_speed, int16_t rtu_steer, int16_t *rty_speedR, int16_t *rty_speedL) {
  int16_t prodSpeed;
  int16_t prodSteer;
  int32_t tmp;

  prodSpeed   = (int16_t)((rtu_speed * (int16_t)SPEED_COEFFICIENT) >> 14);
  prodSteer   = (int16_t)((rtu_steer * (int16_t)STEER_COEFFICIENT) >> 14);

  tmp         = prodSpeed - prodSteer;  
  tmp         = CLAMP(tmp, -32768, 32767);  // Overflow protection
  *rty_speedR = (int16_t)(tmp >> 4);        // Convert from fixed-point to int 
  *rty_speedR = CLAMP(*rty_speedR, INPUT_MIN, INPUT_MAX);

  tmp         = prodSpeed + prodSteer;
  tmp         = CLAMP(tmp, -32768, 32767);  // Overflow protection
  *rty_speedL = (int16_t)(tmp >> 4);        // Convert from fixed-point to int
  *rty_speedL = CLAMP(*rty_speedL, INPUT_MIN, INPUT_MAX);
}



/* =========================== Multiple Tap Function =========================== */

  /* multipleTapDet(int16_t u, uint32_t timeNow, MultipleTap *x)
  * This function detects multiple tap presses, such as double tapping, triple tapping, etc.
  * Inputs:       u = int16_t (input signal); timeNow = uint32_t (current time)  
  * Outputs:      x->b_multipleTap (get the output here)
  */
void multipleTapDet(int16_t u, uint32_t timeNow, MultipleTap *x) {
  uint8_t 	b_timeout;
  uint8_t 	b_hyst;
  uint8_t 	b_pulse;
  uint8_t 	z_pulseCnt;
  uint8_t   z_pulseCntRst;
  uint32_t 	t_time; 

  // Detect hysteresis
  if (x->b_hysteresis) {
    b_hyst = (u > MULTIPLE_TAP_LO);
  } else {
    b_hyst = (u > MULTIPLE_TAP_HI);
  }

  // Detect pulse
  b_pulse = (b_hyst != x->b_hysteresis);

  // Save time when first pulse is detected
  if (b_hyst && b_pulse && (x->z_pulseCntPrev == 0)) {
    t_time = timeNow;
  } else {
    t_time = x->t_timePrev;
  }

  // Create timeout boolean
  b_timeout = (timeNow - t_time > MULTIPLE_TAP_TIMEOUT);

  // Create pulse counter
  if ((!b_hyst) && (x->z_pulseCntPrev == 0)) {
    z_pulseCnt = 0U;
  } else {
    z_pulseCnt = b_pulse;
  }

  // Reset counter if we detected complete tap presses OR there is a timeout
  if ((x->z_pulseCntPrev >= MULTIPLE_TAP_NR) || b_timeout) {
    z_pulseCntRst = 0U;
  } else {
    z_pulseCntRst = x->z_pulseCntPrev;
  }
  z_pulseCnt = z_pulseCnt + z_pulseCntRst;

  // Check if complete tap presses are detected AND no timeout
  if ((z_pulseCnt >= MULTIPLE_TAP_NR) && (!b_timeout)) {
    x->b_multipleTap = !x->b_multipleTap;	// Toggle output
  }

  // Update states
  x->z_pulseCntPrev = z_pulseCnt;
  x->b_hysteresis 	= b_hyst;
  x->t_timePrev 	  = t_time;
}