AMiRo-OS

/************************************************************************************//**

* \file         Demo\ARMCM3_STM32_Olimex_STM32P103_GCC\Boot\main.c

* \brief        Bootloader application source file.

* \ingroup      Boot_ARMCM3_STM32_Olimex_STM32P103_GCC

* \internal

*----------------------------------------------------------------------------------------

*                          C O P Y R I G H T

*----------------------------------------------------------------------------------------

*   Copyright (c) 2012  by Feaser    http://www.feaser.com    All rights reserved

*

*----------------------------------------------------------------------------------------

*                            L I C E N S E

*----------------------------------------------------------------------------------------

* This file is part of OpenBLT. OpenBLT 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.

*

* OpenBLT 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 OpenBLT.

* If not, see <http://www.gnu.org/licenses/>.

*

* A special exception to the GPL is included to allow you to distribute a combined work

* that includes OpenBLT without being obliged to provide the source code for any

* proprietary components. The exception text is included at the bottom of the license

* file <license.html>.

*

* \endinternal

****************************************************************************************/

/****************************************************************************************

* Include files

****************************************************************************************/

#include "boot.h"                                /* bootloader generic header          */

#include "timer.h"

#include "ARMCM3_STM32/types.h"

#include "AMiRo/amiroblt.h"

#include "helper.h"

#include "iodef.h"

/****************************************************************************************

* Defines

****************************************************************************************/

#define RESET_TIMEOUT_MS    100

/****************************************************************************************

* Function prototypes

****************************************************************************************/

static void Init(void);

static void initGpio();

static void initExti();

void configGpioForShutdown();

ErrorStatus handleColdReset();

ErrorStatus handleUartWakeup();

ErrorStatus handleAccelWakeup();

ErrorStatus shutdownDisambiguationProcedure(const uint8_t type);

void shutdownToTransportation(const blt_bool exec_disambiguation);

void shutdownToDeepsleep(const blt_bool exec_disambiguation);

void shutdownToHibernate(const blt_bool exec_disambiguation);

void shutdownAndRestart(const blt_bool exec_disambiguation);

volatile blBackupRegister_t backup_reg;

/****************************************************************************************

* Callback configuration

****************************************************************************************/

void blCallbackShutdownTransportation(void);

void blCallbackShutdownDeepsleep(void);

void blCallbackShutdownHibernate(void);

void blCallbackShutdownRestart(void);

void blCallbackHandleShutdownRequest(void);

const blCallbackTable_t cbtable __attribute__ ((section ("_callback_table"))) = {

  .magicNumber = BL_MAGIC_NUMBER,

  .vBootloader = {BL_VERSION_ID_AMiRoBLT_Beta, BL_VERSION_MAJOR, BL_VERSION_MINOR, 0},

  .vSSSP = {BL_VERSION_ID_SSSP, BL_SSSP_VERSION_MAJOR, BL_SSSP_VERSION_MINOR, 0},

  .vCompiler = {BL_VERSION_ID_GCC, __GNUC__, __GNUC_MINOR__, __GNUC_PATCHLEVEL__},  // currently only GCC is supported

  .cbShutdownHibernate = blCallbackShutdownHibernate,

  .cbShutdownDeepsleep = blCallbackShutdownDeepsleep,

  .cbShutdownTransportation = blCallbackShutdownTransportation,

  .cbShutdownRestart = blCallbackShutdownRestart,

  .cbHandleShutdownRequest = blCallbackHandleShutdownRequest,

  .cb5 = (void*)0,

  .cb6 = (void*)0,

  .cb7 = (void*)0,

  .cb8 = (void*)0,

  .cb9 = (void*)0,

  .cb10 = (void*)0,

  .cb11 = (void*)0

};

/************************************************************************************//**

** \brief     This is the entry point for the bootloader application and is called

**            by the reset interrupt vector after the C-startup routines executed.

** \return    Program return code.

**

****************************************************************************************/

int main(void)

{

  /* initialize the microcontroller */

  Init();

  /* activate some required clocks */

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE);

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB | RCC_APB2Periph_GPIOC | RCC_APB2Periph_GPIOD, ENABLE);

  /* initialize GPIOs and EXTI lines */

  initGpio();

  setLed(BLT_TRUE);

  initExti();

  /* initialize the timer */

  TimerInit();

  /* detect the primary reason for this wakeup/restart */

  backup_reg.wakeup_pri_reason =

      ((RCC_GetFlagStatus(RCC_FLAG_LPWRRST) == SET) ? BL_WAKEUP_PRI_RSN_LPWRRST : 0) |

      ((RCC_GetFlagStatus(RCC_FLAG_WWDGRST) == SET) ? BL_WAKEUP_PRI_RSN_WWDGRST : 0) |

      ((RCC_GetFlagStatus(RCC_FLAG_IWDGRST) == SET) ? BL_WAKEUP_PRI_RSN_IWDGRST : 0) |

      ((RCC_GetFlagStatus(RCC_FLAG_SFTRST) == SET) ? BL_WAKEUP_PRI_RSN_SFTRST : 0)   |

      ((RCC_GetFlagStatus(RCC_FLAG_PORRST) == SET) ? BL_WAKEUP_PRI_RSN_PORRST : 0)   |

      ((RCC_GetFlagStatus(RCC_FLAG_PINRST) == SET) ? BL_WAKEUP_PRI_RSN_PINRST : 0)   |

      ((PWR_GetFlagStatus(PWR_FLAG_WU) == SET) ? BL_WAKEUP_PRI_RSN_WKUP : 0);

  /* when woken from standby mode, detect the secondary reason for thiswakeup/reset */

  if ( (backup_reg.wakeup_pri_reason & BL_WAKEUP_PRI_RSN_WKUP) && (PWR_GetFlagStatus(PWR_FLAG_SB) == SET) ) {

    if (GPIO_ReadInputDataBit(SYS_UART_UP_GPIO, SYS_UART_UP_PIN) == Bit_SET) {

      backup_reg.wakeup_sec_reason = BL_WAKEUP_SEC_RSN_UART;

    } else {

      backup_reg.wakeup_sec_reason = BL_WAKEUP_SEC_RSN_ACCEL;

    }

  } else {

    backup_reg.wakeup_sec_reason = BL_WAKEUP_SEC_RSN_UNKNOWN;

  }

  /* clear the flags */

  RCC_ClearFlag();

  PWR_ClearFlag(PWR_FLAG_WU);

  setLed(BLT_FALSE);

  /* wait 1ms for all signals to become stable */

  msleep(1);

  /* handle different wakeup/reset reasons */

  ErrorStatus status = ERROR;

  if (backup_reg.wakeup_pri_reason & BL_WAKEUP_PRI_RSN_WKUP) {

    /* the system was woken via WKUP pin */

    /* differenciate between two wakeup types */

    switch (backup_reg.wakeup_sec_reason) {

      case BL_WAKEUP_SEC_RSN_UART:

        status = handleUartWakeup();

        break;

      case BL_WAKEUP_SEC_RSN_ACCEL:

        status = handleAccelWakeup();

        break;

      default:

        status = ERROR;

        break;

    }

  } else if (backup_reg.wakeup_pri_reason & BL_WAKEUP_PRI_RSN_PINRST) {

    /* system was woken via NRST pin */

    status = handleColdReset();

  } else {

    /* system was woken/reset for an unexpected reason */

    blinkSOS(1);

    status = handleColdReset();

  }

  /* if something went wrong, signal this failure */

  if (status != SUCCESS) {

    blinkSOSinf();

  }

  return 0;

} /*** end of main ***/

/************************************************************************************//**

** \brief     Initializes the microcontroller.

** \return    none.

**

****************************************************************************************/

static void Init(void)

{

  volatile blt_int32u StartUpCounter = 0, HSEStatus = 0;

  blt_int32u pll_multiplier;

#if (BOOT_FILE_LOGGING_ENABLE > 0) && (BOOT_COM_UART_ENABLE == 0)

  GPIO_InitTypeDef  GPIO_InitStruct;

  USART_InitTypeDef USART_InitStruct;

#endif

  /* reset the RCC clock configuration to the default reset state (for debug purpose) */

  /* set HSION bit */

  RCC->CR |= (blt_int32u)0x00000001;

  /* reset SW, HPRE, PPRE1, PPRE2, ADCPRE and MCO bits */

  RCC->CFGR &= (blt_int32u)0xF8FF0000;

  /* reset HSEON, CSSON and PLLON bits */

  RCC->CR &= (blt_int32u)0xFEF6FFFF;

  /* reset HSEBYP bit */

  RCC->CR &= (blt_int32u)0xFFFBFFFF;

  /* reset PLLSRC, PLLXTPRE, PLLMUL and USBPRE/OTGFSPRE bits */

  RCC->CFGR &= (blt_int32u)0xFF80FFFF;

  /* disable all interrupts and clear pending bits  */

  RCC->CIR = 0x009F0000;

  /* enable HSE */

  RCC->CR |= ((blt_int32u)RCC_CR_HSEON);

  /* wait till HSE is ready and if Time out is reached exit */

  do

  {

    HSEStatus = RCC->CR & RCC_CR_HSERDY;

    StartUpCounter++;

  }

  while((HSEStatus == 0) && (StartUpCounter != 1500));

  /* check if time out was reached */

  if ((RCC->CR & RCC_CR_HSERDY) == RESET)

  {

    /* cannot continue when HSE is not ready */

    ASSERT_RT(BLT_FALSE);

  }

  /* enable flash prefetch buffer */

  FLASH->ACR |= FLASH_ACR_PRFTBE;

  /* reset flash wait state configuration to default 0 wait states */

  FLASH->ACR &= (blt_int32u)((blt_int32u)~FLASH_ACR_LATENCY);

#if (BOOT_CPU_SYSTEM_SPEED_KHZ > 48000)

  /* configure 2 flash wait states */

  FLASH->ACR |= (blt_int32u)FLASH_ACR_LATENCY_2;

#elif (BOOT_CPU_SYSTEM_SPEED_KHZ > 24000)

  /* configure 1 flash wait states */

  FLASH->ACR |= (blt_int32u)FLASH_ACR_LATENCY_1;

#endif

  /* HCLK = SYSCLK */

  RCC->CFGR |= (blt_int32u)RCC_CFGR_HPRE_DIV1;

  /* PCLK2 = HCLK/2 */

  RCC->CFGR |= (blt_int32u)RCC_CFGR_PPRE2_DIV2;

  /* PCLK1 = HCLK/2 */

  RCC->CFGR |= (blt_int32u)RCC_CFGR_PPRE1_DIV2;

  /* reset PLL configuration */

  RCC->CFGR &= (blt_int32u)((blt_int32u)~(RCC_CFGR_PLLSRC | RCC_CFGR_PLLXTPRE | \

                                          RCC_CFGR_PLLMULL));

  /* assert that the pll_multiplier is between 2 and 16 */

  ASSERT_CT((BOOT_CPU_SYSTEM_SPEED_KHZ/BOOT_CPU_XTAL_SPEED_KHZ) >= 2);

  ASSERT_CT((BOOT_CPU_SYSTEM_SPEED_KHZ/BOOT_CPU_XTAL_SPEED_KHZ) <= 16);

  /* calculate multiplier value */

  pll_multiplier = BOOT_CPU_SYSTEM_SPEED_KHZ/BOOT_CPU_XTAL_SPEED_KHZ;

  /* convert to register value */

  pll_multiplier = (blt_int32u)((pll_multiplier - 2) << 18);

  /* set the PLL multiplier and clock source */

  RCC->CFGR |= (blt_int32u)(RCC_CFGR_PLLSRC_HSE | pll_multiplier);

  /* enable PLL */

  RCC->CR |= RCC_CR_PLLON;

  /* wait till PLL is ready */

  while((RCC->CR & RCC_CR_PLLRDY) == 0)

  {

  }

  /* select PLL as system clock source */

  RCC->CFGR &= (blt_int32u)((blt_int32u)~(RCC_CFGR_SW));

  RCC->CFGR |= (blt_int32u)RCC_CFGR_SW_PLL;

  /* wait till PLL is used as system clock source */

  while ((RCC->CFGR & (blt_int32u)RCC_CFGR_SWS) != (blt_int32u)0x08)

  {

  }

  /* remap JTAG pins */

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);

  AFIO->MAPR &= ~(blt_int32u)((blt_int32u)0x7 << 24);

  AFIO->MAPR |=  (blt_int32u)((blt_int32u)0x2 << 24);

  /* all input */

#if (BOOT_COM_CAN_ENABLE > 0 || BOOT_GATE_CAN_ENABLE > 0)

  /* enable clocks for CAN transmitter and receiver pins (GPIOB and AFIO) */

  RCC->APB2ENR |= (blt_int32u)(0x00000004 | 0x00000001);

  /* configure CAN Rx (GPIOA11) as alternate function input */

  /* first reset the configuration */

  GPIOA->CRH &= ~(blt_int32u)((blt_int32u)0xf << 12);

  /* CNF8[1:0] = %01 and MODE8[1:0] = %00 */

  GPIOA->CRH |= (blt_int32u)((blt_int32u)0x4 << 12);

  /* configure CAN Tx (GPIOA12) as alternate function push-pull */

  /* first reset the configuration */

  GPIOA->CRH &= ~(blt_int32u)((blt_int32u)0xf << 16);

  /* CNF9[1:0] = %11 and MODE9[1:0] = %11 */

  GPIOA->CRH |= (blt_int32u)((blt_int32u)0xb << 16);

  /* remap CAN1 pins to PortA */

  AFIO->MAPR &= ~(blt_int32u)((blt_int32u)0x3 << 13);

  AFIO->MAPR |=  (blt_int32u)((blt_int32u)0x0 << 13);

#endif

#if (BOOT_COM_UART_ENABLE > 0 || BOOT_GATE_UART_ENABLE > 0)

  /* enable clocks for USART1 peripheral, transmitter and receiver pins (GPIOA and AFIO) */

  RCC->APB2ENR |= (blt_int32u)(0x00004000 | 0x00000004 | 0x00000001);

  /* configure USART1 Tx (GPIOA9) as alternate function push-pull */

  /* first reset the configuration */

  GPIOA->CRH &= ~(blt_int32u)((blt_int32u)0xf << 4);

  /* CNF2[1:0] = %10 and MODE2[1:0] = %11 */

  GPIOA->CRH |= (blt_int32u)((blt_int32u)0xb << 4);

  /* configure USART1 Rx (GPIOA10) as alternate function input floating */

  /* first reset the configuration */

  GPIOA->CRH &= ~(blt_int32u)((blt_int32u)0xf << 8);

  /* CNF2[1:0] = %01 and MODE2[1:0] = %00 */

  GPIOA->CRH |= (blt_int32u)((blt_int32u)0x4 << 8);

#endif

} /*** end of Init ***/

/*

 * Initializes all GPIO used by the bootloader

 */

static void initGpio() {

  GPIO_InitTypeDef gpio_init;

  /*

   * OUTPUTS

   */

  /* initialize LED and push it up (inactive) */

  GPIO_SetBits(LED_GPIO, LED_PIN);

  gpio_init.GPIO_Pin    = LED_PIN;

  gpio_init.GPIO_Mode   = GPIO_Mode_Out_PP;

  gpio_init.GPIO_Speed  = GPIO_Speed_50MHz;

  GPIO_Init(LED_GPIO, &gpio_init);

  /* initialize SYS_PD_N and let it go (inactive) */

  GPIO_SetBits(SYS_PD_N_GPIO, SYS_PD_N_PIN);

  gpio_init.GPIO_Pin    = SYS_PD_N_PIN;

  gpio_init.GPIO_Mode   = GPIO_Mode_Out_OD;

  gpio_init.GPIO_Speed  = GPIO_Speed_50MHz;

  GPIO_Init(SYS_PD_N_GPIO, &gpio_init);

  /* initialize SYS_SYNC_N and pull it down (active) */

  GPIO_ResetBits(SYS_SYNC_N_GPIO, SYS_SYNC_N_PIN);

  gpio_init.GPIO_Pin    = SYS_SYNC_N_PIN;

  gpio_init.GPIO_Mode   = GPIO_Mode_Out_OD;

  gpio_init.GPIO_Speed  = GPIO_Speed_50MHz;

  GPIO_Init(SYS_SYNC_N_GPIO, &gpio_init);

  /* initialize SYS_WARMST_N and let it go (active) */

  GPIO_SetBits(SYS_WARMRST_N_GPIO, SYS_WARMRST_N_PIN);

  gpio_init.GPIO_Pin    = SYS_WARMRST_N_PIN;

  gpio_init.GPIO_Mode   = GPIO_Mode_Out_OD;

  gpio_init.GPIO_Speed  = GPIO_Speed_50MHz;

  GPIO_Init(SYS_WARMRST_N_GPIO, &gpio_init);

  /* initialize SYS_UART_UP and let it go (inactive) */

  GPIO_SetBits(SYS_UART_UP_GPIO, SYS_UART_UP_PIN);

  gpio_init.GPIO_Pin    = SYS_UART_UP_PIN;

  gpio_init.GPIO_Mode   = GPIO_Mode_Out_OD;

  gpio_init.GPIO_Speed  = GPIO_Speed_50MHz;

  GPIO_Init(SYS_UART_UP_GPIO, &gpio_init);

  /* initialize PATH_DCEN and pull it down (inactive) */

  GPIO_ResetBits(PATH_DCEN_GPIO, PATH_DCEN_PIN);

  gpio_init.GPIO_Pin    = PATH_DCEN_PIN;

  gpio_init.GPIO_Mode   = GPIO_Mode_Out_PP;

  gpio_init.GPIO_Speed  = GPIO_Speed_50MHz;

  GPIO_Init(PATH_DCEN_GPIO, &gpio_init);

  /*

   * INPUTS

   */

  /* initialize the input ACCEL_INT_N */

  gpio_init.GPIO_Pin    = ACCEL_INT_N_PIN;

  gpio_init.GPIO_Mode   = GPIO_Mode_IN_FLOATING;

  gpio_init.GPIO_Speed  = GPIO_Speed_50MHz;

  GPIO_Init(ACCEL_INT_N_GPIO, &gpio_init);

  return;

} /*** end of initGpio ***/

/*

 * Initialize all EXTI lines

 */

static void initExti() {

  /* configure EXTI lines */

  GPIO_EXTILineConfig(GPIO_PortSourceGPIOC, GPIO_PinSource1); // SYS_SYNC_N

  GPIO_EXTILineConfig(GPIO_PortSourceGPIOD, GPIO_PinSource2); // SYS_WARMRST_N

  GPIO_EXTILineConfig(GPIO_PortSourceGPIOC, GPIO_PinSource3); // PATH_DCSTAT

  GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource5); // COMPASS_DRDY

  GPIO_EXTILineConfig(GPIO_PortSourceGPIOC, GPIO_PinSource8); // SYS_PD_N

  GPIO_EXTILineConfig(GPIO_PortSourceGPIOC, GPIO_PinSource9); // SYS_REG_EN

  GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource12); // IR_INT

  GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource13); // GYRO_DRDY

  GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource14); // SYS_UART_UP

  GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource15); // ACCEL_INT_N

  return;

} /*** end of initExti ***/

/*

 * Signals, which type of low-power mode the system shall enter after the shutdown sequence.

 */

ErrorStatus shutdownDisambiguationProcedure(const uint8_t type) {

  GPIO_SetBits(SYS_SYNC_N_GPIO, SYS_SYNC_N_PIN);

  ErrorStatus ret_val = ERROR;

  switch (type) {

    case BL_SHUTDOWN_PRI_RSN_UNKNOWN:

    case BL_SHUTDOWN_PRI_RSN_HIBERNATE:

    case BL_SHUTDOWN_PRI_RSN_DEEPSLEEP:

    case BL_SHUTDOWN_PRI_RSN_TRANSPORT:

    {

      // broadcast a number of pulses, depending on the argument

      uint8_t pulse_counter = 0;

      for (pulse_counter = 0; pulse_counter < type; ++pulse_counter) {

        msleep(1);

        GPIO_ResetBits(SYS_SYNC_N_GPIO, SYS_SYNC_N_PIN);

        msleep(1);

        GPIO_SetBits(SYS_SYNC_N_GPIO, SYS_SYNC_N_PIN);

      }

      // wait for timeout

      msleep(10);

      ret_val = SUCCESS;

      break;

    }

    case BL_SHUTDOWN_PRI_RSN_RESTART:

    {

      // since there is no ambiguity for restart requests, no pulses are generated

      msleep(10);

      ret_val = SUCCESS;

      break;

    }

    default:

      ret_val = ERROR;

      break;

  }

  return ret_val;

} /*** end of shutdownDisambiguationProcedure ***/

/*

 * Final shutdown of the system to enter transportation mode.

 */

void shutdownToTransportation(const blt_bool exec_disambiguation) {

  /* configure some criticpal GPIOs as input

   * This is required, because otherwise some hardware might be powered through these signals */

  configGpioForShutdown();

  /* turn off the motors */

  GPIO_ResetBits(POWER_EN_GPIO, POWER_EN_PIN);

  /* deactivate the WKUP pin */

  PWR_WakeUpPinCmd(DISABLE);

  /* deactivate any RTC related events */

  RTC_ITConfig(RTC_IT_ALR | RTC_IT_OW | RTC_IT_SEC, DISABLE);

  RTC_ClearFlag(~0);

  /* disable the IWDG */

  IWDG_ReloadCounter();

  /* wait for all boards to be ready for shutdown */

  GPIO_SetBits(SYS_SYNC_N_GPIO, SYS_SYNC_N_PIN);

  if (GPIO_ReadInputDataBit(SYS_REG_EN_GPIO, SYS_REG_EN_PIN) == Bit_SET) {

    // this must skipped if the pullup voltage (VIO3.3) is not active

    setLed(BLT_TRUE);

    waitForSignal(SYS_SYNC_N_GPIO, SYS_SYNC_N_PIN, Bit_SET);

    setLed(BLT_FALSE);

  }

  if (exec_disambiguation == BLT_TRUE) {

    /* execute disambiguation procedure and signal all modules to enter transportation mode */

    if (shutdownDisambiguationProcedure(BL_SHUTDOWN_PRI_RSN_TRANSPORT) != SUCCESS) {

      blinkSOS(1);

      msleep(10);

    }

  }

  /* morse 'OK' via the LED to signal that shutdown was successful */

  blinkOK(1);

  /* enter standby mode */

  PWR_EnterSTANDBYMode();

  return;

} /*** end of shutdownToTransportation ***/

/*

 * Final shutdown of the system to enter deepsleep mode.

 */

void shutdownToDeepsleep(const blt_bool exec_disambiguation) {

  /* configure some criticpal GPIOs as input

   * This is required, because otherwise some hardware might be powered through these signals */

  configGpioForShutdown();

  /* turn off the motors */

  GPIO_ResetBits(POWER_EN_GPIO, POWER_EN_PIN);

  /* deactivate the WKUP pin */

  PWR_WakeUpPinCmd(ENABLE);

  /*

   * Configuration of RTC and IWDG belongs to the OS.

   */

  /* wait for all boards to be ready for shutdown */

  GPIO_SetBits(SYS_SYNC_N_GPIO, SYS_SYNC_N_PIN);

  if (GPIO_ReadInputDataBit(SYS_REG_EN_GPIO, SYS_REG_EN_PIN) == Bit_SET) {

    // this must skipped if the pullup voltage (VIO3.3) is not active

    setLed(BLT_TRUE);

    waitForSignal(SYS_SYNC_N_GPIO, SYS_SYNC_N_PIN, Bit_SET);

    setLed(BLT_FALSE);

  }

  if (exec_disambiguation == BLT_TRUE) {

    /* execute disambiguation procedure and signal all modules to enter deepsleep mode */

    if (shutdownDisambiguationProcedure(BL_SHUTDOWN_PRI_RSN_DEEPSLEEP) != SUCCESS) {

      blinkSOS(1);

      msleep(10);

    }

  }

  /* morse 'OK' via the LED to signal that shutdown was successful */

  blinkOK(1);

  /* enter standby mode */

  PWR_EnterSTANDBYMode();

  return;

} /*** end of shutdownToDeepsleep ***/

/*

 * Final shutdown of the system to enter hibernate mode.

 */

void shutdownToHibernate(const blt_bool exec_disambiguation) {

  /* configure some criticpal GPIOs as input

   * This is required, because otherwise some hardware might be powered through these signals */

  configGpioForShutdown();

  /* turn off the motors */

  GPIO_ResetBits(POWER_EN_GPIO, POWER_EN_PIN);

  /* deactivate the WKUP pin */

  PWR_WakeUpPinCmd(ENABLE);

  /*

   * Configuration of RTC and IWDG belongs to the OS.

   */

  /* wait for all boards to be ready for shutdown */

  GPIO_SetBits(SYS_SYNC_N_GPIO, SYS_SYNC_N_PIN);

  if (GPIO_ReadInputDataBit(SYS_REG_EN_GPIO, SYS_REG_EN_PIN) == Bit_SET) {

    // this must skipped if the pullup voltage (VIO3.3) is not active

    setLed(BLT_TRUE);

    waitForSignal(SYS_SYNC_N_GPIO, SYS_SYNC_N_PIN, Bit_SET);

    setLed(BLT_FALSE);

  }

  if (exec_disambiguation == BLT_TRUE) {

    /* execute disambiguation procedure and signal all modules to enter deepsleep mode */

    if (shutdownDisambiguationProcedure(BL_SHUTDOWN_PRI_RSN_HIBERNATE) != SUCCESS) {

      blinkSOS(1);

      msleep(10);

    }

  }

  /* morse 'OK' via the LED to signal that shutdown was successful */

  blinkOK(1);

  /* enter standby mode */

  PWR_EnterSTANDBYMode();

  return;

} /* end of shutdownToHibernate ***/

/*

 * Final shutdown of the system and restart.

 */

void shutdownAndRestart(const blt_bool exec_disambiguation) {

  /* configure some criticpal GPIOs as input

   * This is required, because otherwise some hardware might be powered through these signals */

  configGpioForShutdown();

  /* turn off the motors */

  GPIO_ResetBits(POWER_EN_GPIO, POWER_EN_PIN);

  /* prepare for low-power mode */

  PWR_WakeUpPinCmd(DISABLE); // disable WKUP pin

  RTC_ITConfig(RTC_IT_ALR | RTC_IT_OW | RTC_IT_SEC, DISABLE); // unset RTC events

  RTC_ClearFlag(~0); // clear pending RTC events

  IWDG_ReloadCounter(); // disable IWDG

  /* wait for all boards to be ready for shutdown */

  GPIO_SetBits(SYS_SYNC_N_GPIO, SYS_SYNC_N_PIN);

  if (GPIO_ReadInputDataBit(SYS_REG_EN_GPIO, SYS_REG_EN_PIN) == Bit_SET) {

    // this must skipped if the pullup voltage (VIO3.3) is not active

    setLed(BLT_TRUE);

    waitForSignal(SYS_SYNC_N_GPIO, SYS_SYNC_N_PIN, Bit_SET);

    setLed(BLT_FALSE);

  }

  if (exec_disambiguation == BLT_TRUE) {

    /* execute disambiguation procedure and signal all modules to restart in default mode */

    if (shutdownDisambiguationProcedure(BL_SHUTDOWN_PRI_RSN_RESTART) != SUCCESS) {

      blinkSOS(1);

      msleep(10);

    }

  }

  /* morse 'OK' via the LED to signal that shutdown was successful */

  blinkOK(1);

  /* enter standby mode */

  PWR_EnterSTANDBYMode();

  /*

   * Even though this module will not restart the system by its own, the PowerManagement will reset the system.

   */

  return;

} /*** end of shutdownAndRestart***/

/*

 * Configures some GPIO pins as inputs for safety reasons.

 * Under certain circumstances, these pins might power hardware that is supposed to be shut down.

 */

void configGpioForShutdown() {

  /* setup the configuration */

  GPIO_InitTypeDef gpio_init;

  gpio_init.GPIO_Mode   = GPIO_Mode_IN_FLOATING;

  gpio_init.GPIO_Speed  = GPIO_Speed_50MHz;

  /* configure SYS_UART_TX */

  gpio_init.GPIO_Pin = SYS_UART_TX_PIN;

  GPIO_Init(SYS_UART_TX_GPIO, &gpio_init);

  /* configure CAN_TX */

  gpio_init.GPIO_Pin = CAN_TX_PIN;

  GPIO_Init(CAN_TX_GPIO, &gpio_init);

  /* configure all MOTION (SPI) signals */

  gpio_init.GPIO_Pin = MOTION_SCLK_PIN;

  GPIO_Init(MOTION_SCLK_GPIO, &gpio_init);

  gpio_init.GPIO_Pin = MOTION_MISO_PIN;

  GPIO_Init(MOTION_MISO_GPIO, &gpio_init);

  gpio_init.GPIO_Pin = MOTION_MOSI_PIN;

  GPIO_Init(MOTION_MOSI_GPIO, &gpio_init);

  gpio_init.GPIO_Pin = ACCEL_SS_N_PIN;

  GPIO_Init(ACCEL_SS_N_GPIO, &gpio_init);

  gpio_init.GPIO_Pin = GYRO_SS_N_PIN;

  GPIO_Init(GYRO_SS_N_GPIO, &gpio_init);

  return;

} /*** end of configGpioForShutdown ***/

/*

 * System was reset via the NRST pin or the reason could not be detected.

 * In this case, there are three possibilities how to act:

 * 1) When the SYS_WARMRST_N signal becomes inactive, flashing mode is entered and the system will try to load the OS.

 * 2) When the SYS_UART_UP signal becomes active (low), the system will enter hibernate mode to enable charging via the pins.

 * 3) If none of both happens and a timeout occurs, the system enters deepsleep mode.

 */

ErrorStatus handleColdReset() {

  /* wait until either the SYS_WARMRST_N signal goes up, or SYS_UART_UP goes down */

  enum CRST_SIG {CRST_SIG_SYS_WARMRST_N,

                 CRST_SIG_SYS_UART_UP,

                 CRST_SIG_TIMEOUT

                } sig;

  uint32_t loopStartTime = 0;

  saTimerUpdate(&loopStartTime);

  uint32_t currentTime = loopStartTime;

  setLed(BLT_TRUE);

  while (1) {

    /* read the input signals */

    if (GPIO_ReadInputDataBit(SYS_REG_EN_GPIO, SYS_REG_EN_PIN) == Bit_SET &&

        GPIO_ReadInputDataBit(SYS_WARMRST_N_GPIO, SYS_WARMRST_N_PIN) == Bit_SET) {

      sig = CRST_SIG_SYS_WARMRST_N;

      break;

    }

    if (GPIO_ReadInputDataBit(SYS_UART_UP_GPIO, SYS_UART_UP_PIN) == Bit_RESET) {

      sig = CRST_SIG_SYS_UART_UP;

      break;

    }

    /* check for a timeout */

    saTimerUpdate(&currentTime);

    if (currentTime > loopStartTime + RESET_TIMEOUT_MS) {

      sig = CRST_SIG_TIMEOUT;

      break;

    }

  }

  setLed(BLT_FALSE);

  /* depending on the signal, react accordingly */

  switch (sig) {

    /* activation of the slave modules signales to boot the OS */

    case CRST_SIG_SYS_WARMRST_N:

    {

      /* enable CAN clock */

      RCC_APB1PeriphClockCmd(RCC_APB1Periph_CAN1, ENABLE);

      /* initialize the bootloader */

      BootInit();

      /* start the infinite program loop */

      uint32_t loopStartTime = 0;

      saTimerUpdate(&loopStartTime);

      uint32_t currentTime = loopStartTime;

      while (1)

      {

//        /* make the LED "double-blink" */

//        saTimerUpdate(&currentTime);

//        if (currentTime < loopStartTime + 50) {

//          setLed(BLT_TRUE);

//        } else if (currentTime < loopStartTime + 50+100) {

//          setLed(BLT_FALSE);

//        } else if (currentTime < loopStartTime + 50+100+50) {

//          setLed(BLT_TRUE);

//        } else if ( currentTime < loopStartTime + 50+100+50+300) {

//          setLed(BLT_FALSE);

//        } else {

//          loopStartTime = currentTime;

//        }

        /* run the bootloader task */

        BootTask();

        /* check the SYS_PD_N signal */

        if (GPIO_ReadInputDataBit(SYS_PD_N_GPIO, SYS_PD_N_PIN) == Bit_RESET) {

          blCallbackHandleShutdownRequest();

          return SUCCESS;

        }

      }

      break;

    }

    /* activation of the UART_UP signal indicates that this module shall enter hibernate mode */

    case CRST_SIG_SYS_UART_UP:

    {

      /* indicate that the MCU is busy */

      GPIO_ResetBits(SYS_UART_UP_GPIO, SYS_UART_UP_PIN);

      /* enable the charging pins */

      GPIO_SetBits(PATH_DCEN_GPIO, PATH_DCEN_PIN);

      /* wait some time so the systen voltage (VSYS) is stable if it is supplied via the pins */

      msleep(10);

      /* indicate that the MCU is not busy anymore */

      GPIO_SetBits(SYS_UART_UP_GPIO, SYS_UART_UP_PIN);

      /* configure the accelerometer external interrupt as event */

      EXTI_InitTypeDef exti;

      exti.EXTI_Line = EXTI_Line15;

      exti.EXTI_Mode = EXTI_Mode_Event;

      exti.EXTI_Trigger = EXTI_Trigger_Falling;

      exti.EXTI_LineCmd = ENABLE;

      EXTI_Init(&exti);

      /* sleep until something happens */

      __WFE();

      /* clear all pending EXTI events */

      EXTI_DeInit();

      EXTI_ClearFlag(EXTI_Line15);

      /* handle accelerometer wakeup

       * note: In fact, the only events that will occur at this point are an interrupt event from the accelerometer, or a

       * system reset from the PowerManagement via the NRST pin. Thus, if the following code is reached, it must have

       * been the accelerometer.

       */

      /* as as after a normal wakeup from the accelerometer */

      return handleAccelWakeup();

      break;

    }

    /* if a timeout occurred, the system enters deepsleep mode */

    case CRST_SIG_TIMEOUT:

    {

      /* reconfigure the LED_GPIO as input so it will not light up (and thus save energy) */

      GPIO_InitTypeDef gpio_init;

      gpio_init.GPIO_Pin    = LED_PIN;

      gpio_init.GPIO_Mode   = GPIO_Mode_IN_FLOATING;

      gpio_init.GPIO_Speed  = GPIO_Speed_50MHz;

      GPIO_Init(LED_GPIO, &gpio_init);

      /* reconfigure SYS_PD_N as input so the callback will not indicate a shutdown */

      gpio_init.GPIO_Pin    = SYS_PD_N_PIN;

      gpio_init.GPIO_Mode   = GPIO_Mode_IN_FLOATING;

      gpio_init.GPIO_Speed  = GPIO_Speed_50MHz;

      GPIO_Init(SYS_PD_N_GPIO, &gpio_init);

      blCallbackShutdownDeepsleep();

      break;

    }

    default:

      break;

  }

  return ERROR;

} /*** end of handleColdReset ***/

/*

 * System was woken up via the WKUP pin and the SYS_UART_UP signal was found to be responsible.

 * In this case, the system starts as after a cold reset.

 */

ErrorStatus handleUartWakeup() {

  return handleColdReset();

} /*** end of handleUartWakeup ***/

/*

 * System was woken up via the WKUP pin and the ACCEL_INT_N signal was found to be responsible.

 * The SYS_UART_UP signal is used to wake the PowerManagement before a normal cold reset is performed.

 */

ErrorStatus handleAccelWakeup() {

  /* wakeup the PowerManegement (ensure that the pulse is detected) */

  GPIO_ResetBits(SYS_UART_UP_GPIO, SYS_UART_UP_PIN);

  msleep(1);

  GPIO_SetBits(SYS_UART_UP_GPIO, SYS_UART_UP_PIN);

  return handleColdReset();

} /*** end of handleAccelWakeu ***/

/*

 * Callback function that handles the system shutdown and enters transportation mode.

 * When called from a multithreaded environment, it must be ensured that no other thread will preempt this function.

 * In transportation low-power mode the system can only be woken up by pulling down the NRST signal.

 * Furthermore, the system can not be charged when in transportation mode.

 */

void blCallbackShutdownTransportation(void) {

  /* make sure that the required clocks are activated */

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE);

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB | RCC_APB2Periph_GPIOC | RCC_APB2Periph_GPIOD, ENABLE);

  /* set/keep the SYS_SYNC and SYS_PD signals active */

  GPIO_ResetBits(SYS_SYNC_N_GPIO, SYS_SYNC_N_PIN);

  GPIO_ResetBits(SYS_PD_N_GPIO, SYS_PD_N_PIN);

  setLed(BLT_TRUE);

  saTimerInit();

  shutdownToTransportation(BLT_TRUE);

  return;

} /*** end of blCallbackShutdownTransportation ***/

/*

 * Callback function that handles the system shutdown and enters deepsleep mode.

 * When called from a multithreaded environment, it must be ensured that no other thread will preempt this function.

 * In deepsleep low-power mode the system can only be woken up via the NRST or the WKUP signal, or the RTC or IWDG, if configured.

 */

void blCallbackShutdownDeepsleep(void) {

  /* make sure that the required clocks are activated */

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE);

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB | RCC_APB2Periph_GPIOC | RCC_APB2Periph_GPIOD, ENABLE);

  /* set/keep the SYS_SYNC and SYS_PD signals active */

  GPIO_ResetBits(SYS_SYNC_N_GPIO, SYS_SYNC_N_PIN);

  GPIO_ResetBits(SYS_PD_N_GPIO, SYS_PD_N_PIN);

  saTimerInit();

  shutdownToDeepsleep(BLT_TRUE);

  return;

} /*** end of blCallbackShutdownDeepsleep ***/

/*

 * Callback function that handles the system shutdown and enters hibernate mode.

 * When called from a multithreaded environment, it must be ensured that no other thread will preempt this function.

 */

void blCallbackShutdownHibernate(void) {

  /* make sure that the required clocks are activated */

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE);

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB | RCC_APB2Periph_GPIOC | RCC_APB2Periph_GPIOD, ENABLE);

  /* set/keep the SYS_SYNC and SYS_PD signals active */

  GPIO_ResetBits(SYS_SYNC_N_GPIO, SYS_SYNC_N_PIN);

  GPIO_ResetBits(SYS_PD_N_GPIO, SYS_PD_N_PIN);

  saTimerInit();

  shutdownToHibernate(BLT_TRUE);

  return;

} /*** end of blCallbackShutdownHibernate ***/

/*

 * Callback function that handles the system shutdown and initializes a restart.

 * When called from a multithreaded environment, it must be ensured that no other thread will preempt this function.

 */

void blCallbackShutdownRestart(void) {

  /* make sure that the required clocks are activated */

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE);

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB | RCC_APB2Periph_GPIOC | RCC_APB2Periph_GPIOD, ENABLE);

  /* set/keep the SYS_SYNC and SYS_PD signal active */

  GPIO_ResetBits(SYS_SYNC_N_GPIO, SYS_SYNC_N_PIN);

  GPIO_ResetBits(SYS_PD_N_GPIO, SYS_PD_N_PIN);

  /* ensure that all modules had a chance to detect the pulse on SYS_PD_N */

  saTimerInit();

  msleep(1);

  GPIO_SetBits(SYS_PD_N_GPIO, SYS_PD_N_PIN);

  msleep(1);

  shutdownAndRestart(BLT_TRUE);

  return;

} /*** end of blCallbackRestart ***/

/*

 * Callback function that handles a system shutdown/restart request from another module.

 * Depending on the result of the disambiguation procedure, the module will enter the according low-power mode or restart.

 * When called from a multithreaded environment, it must be ensured that no other thread will preempt this function.

 */

void blCallbackHandleShutdownRequest(void) {

  /* make sure that the required clocks are activated */

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE);

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB | RCC_APB2Periph_GPIOC | RCC_APB2Periph_GPIOD, ENABLE);

  /* set/keep the SYS_SYNC and SYS_PD signal active */

  GPIO_ResetBits(SYS_SYNC_N_GPIO, SYS_SYNC_N_PIN);

  GPIO_ResetBits(SYS_PD_N_GPIO, SYS_PD_N_PIN);

  /* initialized the standalone timer */

  saTimerInit();

  setLed(BLT_TRUE);

  /* deactivate SYS_PD_N and ensure that all modules had a chance to detect the falling edge */

  msleep(1);

  GPIO_SetBits(SYS_PD_N_GPIO, SYS_PD_N_PIN);

  msleep(1);

  /* wait for all boards to be ready for shutdown */

  GPIO_SetBits(SYS_SYNC_N_GPIO, SYS_SYNC_N_PIN);

  if (GPIO_ReadOutputDataBit(SYS_REG_EN_GPIO, SYS_REG_EN_PIN) == Bit_SET) {

    // this must skipped if the pullup voltage (VIO3.3) is not active

    setLed(BLT_TRUE);

    waitForSignal(SYS_SYNC_N_GPIO, SYS_SYNC_N_PIN, Bit_SET);

    setLed(BLT_FALSE);

  }

  /* check ths SYS_PD_N signal, whether the system shall shutdown or restart */

  blt_bool shutdown_nrestart = (GPIO_ReadInputDataBit(SYS_PD_N_GPIO, SYS_PD_N_PIN) == Bit_RESET) ? BLT_TRUE : BLT_FALSE;

  /* disambiguation procedure (passive) */

  uint32_t pulse_counter = 0;

  while (waitForSignalTimeout(SYS_SYNC_N_GPIO, SYS_SYNC_N_PIN, Bit_RESET, 10)) {

    waitForSignal(SYS_SYNC_N_GPIO, SYS_SYNC_N_PIN, Bit_SET);

    ++pulse_counter;

  }

  /* evaluate and hanlde disambiguation result */

  if (shutdown_nrestart == BLT_TRUE) {

    /* shutdown request */

    /* handle special cases */

    if (pulse_counter == BL_SHUTDOWN_PRI_RSN_UNKNOWN) {

      /* no pulse at all was received */

      pulse_counter = BL_SHUTDOWN_PRI_RSN_DEFAULT;

    } else if (pulse_counter != BL_SHUTDOWN_PRI_RSN_HIBERNATE &&

               pulse_counter != BL_SHUTDOWN_PRI_RSN_DEEPSLEEP &&

               pulse_counter != BL_SHUTDOWN_PRI_RSN_TRANSPORT) {

      /* invalid number of pulses received */

      blinkSOS(1);

      pulse_counter = BL_SHUTDOWN_PRI_RSN_DEFAULT;

    }

    switch (pulse_counter) {

      case BL_SHUTDOWN_PRI_RSN_HIBERNATE:

        shutdownToHibernate(BLT_FALSE);

        break;

      case BL_SHUTDOWN_PRI_RSN_DEEPSLEEP:

        shutdownToDeepsleep(BLT_FALSE);

        break;

      case BL_SHUTDOWN_PRI_RSN_TRANSPORT:

        shutdownToTransportation(BLT_FALSE);

        break;

    }

  } else {

    /* restart request */

    /* there is no ambiguity for restart, so it is ignored */

    shutdownAndRestart(BLT_FALSE);

  }

  /* if this code is reached, the system did neither shut down, nor restart.

   * This must never be the case!

   */

  blinkSOSinf();

  return;

} /*** end of blCallbackHandleShutdownRequest ***/

/*********************************** end of main.c *************************************/