AMiRo-OS

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

* \file         Demo\ARMCM4_STM32_Olimex_STM32E407_GCC\Boot\main.c

* \brief        Bootloader application source file.

* \ingroup      Boot_ARMCM4_STM32_Olimex_STM32E407_GCC

* \internal

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

*                          C O P Y R I G H T

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

*   Copyright (c) 2013  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 "stm32f4xx.h"                           /* STM32 registers                    */

#include "stm32f4xx_conf.h"                      /* STM32 peripheral drivers           */

#include "com.h"

#include "ARMCM4_STM32/types.h"

#include "AMiRo/amiroblt.h"

#include "AMiRo/helper.h"

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

* Defines

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

#define WKUP_GPIO               GPIOA

#define WKUP_PIN                GPIO_Pin_0

#define SYS_UART_TX_GPIO        GPIOA

#define SYS_UART_TX_PIN         GPIO_Pin_2

#define SYS_UART_RX_GPIO        GPIOA

#define SYS_UART_RX_PIN         GPIO_Pin_3

#define SYS_SPI_SS0_N_GPIO      GPIOA

#define SYS_SPI_SS0_N_PIN       GPIO_Pin_4

#define SYS_SPI_SCLK_GPIO       GPIOA

#define SYS_SPI_SCLK_PIN        GPIO_Pin_5

#define SYS_SPI_MISO_GPIO       GPIOA

#define SYS_SPI_MISO_PIN        GPIO_Pin_6

#define SYS_SPI_MOSI_GPIO       GPIOA

#define SYS_SPI_MOSI_PIN        GPIO_Pin_7

#define SYS_REG_EN_GPIO         GPIOA

#define SYS_REG_EN_PIN          GPIO_Pin_8

#define PROG_RX_GPIO            GPIOA

#define PROG_RX_PIN             GPIO_Pin_9

#define PROG_TX_GPIO            GPIOA

#define PROG_TX_PIN             GPIO_Pin_10

#define CAN_RX_GPIO             GPIOA

#define CAN_RX_PIN              GPIO_Pin_11

#define CAN_TX_GPIO             GPIOA

#define CAN_TX_PIN              GPIO_Pin_12

#define SWDIO_GPIO              GPIOA

#define SWDIO_PIN               GPIO_Pin_13

#define SWCLK_GPIO              GPIOA

#define SWCLK_PIN               GPIO_Pin_14

#define SYS_SPI_SS1_N_GPIO      GPIOA

#define SYS_SPI_SS1_N_PIN       GPIO_Pin_15

#define IR_INT1_N_GPIO          GPIOB

#define IR_INT1_N_PIN           GPIO_Pin_0

#define VSYS_SENSE_GPIO         GPIOB

#define VSYS_SENSE_PIN          GPIO_Pin_1

#define POWER_EN_GPIO           GPIOB

#define POWER_EN_PIN            GPIO_Pin_2

#define SYS_UART_DN_GPIO        GPIOB

#define SYS_UART_DN_PIN         GPIO_Pin_3

#define CHARGE_STAT2A_GPIO      GPIOB

#define CHARGE_STAT2A_PIN       GPIO_Pin_4

#define BUZZER_GPIO             GPIOB

#define BUZZER_PIN              GPIO_Pin_5

#define GAUGE_BATLOW2_GPIO      GPIOB

#define GAUGE_BATLOW2_PIN       GPIO_Pin_6

#define GAUGE_BATGD2_N_GPIO     GPIOB

#define GAUGE_BATGD2_N_PIN      GPIO_Pin_7

#define GAUGE_SCL2_GPIO         GPIOB

#define GAUGE_SCL2_PIN          GPIO_Pin_8

#define GAUGE_SDA2_GPIO         GPIOB

#define GAUGE_SDA2_PIN          GPIO_Pin_9

#define GAUGE_SCL1_GPIO         GPIOB

#define GAUGE_SCL1_PIN          GPIO_Pin_10

#define GAUGE_SDA1_GPIO         GPIOB

#define GAUGE_SDA1_PIN          GPIO_Pin_11

#define LED_GPIO                GPIOB

#define LED_PIN                 GPIO_Pin_12

#define BT_RTS_GPIO             GPIOB

#define BT_RTS_PIN              GPIO_Pin_13

#define BT_CTS_GPIO             GPIOB

#define BT_CTS_PIN              GPIO_Pin_14

#define SYS_UART_UP_GPIO        GPIOB

#define SYS_UART_UP_PIN         GPIO_Pin_15

#define CHARGE_STAT1A_GPIO      GPIOC

#define CHARGE_STAT1A_PIN       GPIO_Pin_0

#define GAUGE_BATLOW1_GPIO      GPIOC

#define GAUGE_BATLOW1_PIN       GPIO_Pin_1

#define GAUGE_BATGD1_N_GPIO     GPIOC

#define GAUGE_BATGD1_N_PIN      GPIO_Pin_2

#define CHARGE_EN1_N_GPIO       GPIOC

#define CHARGE_EN1_N_PIN        GPIO_Pin_3

#define IR_INT2_N_GPIO          GPIOC

#define IR_INT2_N_PIN           GPIO_Pin_4

#define TOUCH_INT_N_GPIO        GPIOC

#define TOUCH_INT_N_PIN         GPIO_Pin_5

#define SYS_DONE_GPIO           GPIOC

#define SYS_DONE_PIN            GPIO_Pin_6

#define SYS_PROG_N_GPIO         GPIOC

#define SYS_PROG_N_PIN          GPIO_Pin_7

#define PATH_DC_GPIO            GPIOC

#define PATH_DC_PIN             GPIO_Pin_8

#define SYS_SPI_DIR_GPIO        GPIOC

#define SYS_SPI_DIR_PIN         GPIO_Pin_9

#define BT_RX_GPIO              GPIOC

#define BT_RX_PIN               GPIO_Pin_10

#define BT_TX_GPIO              GPIOC

#define BT_TX_PIN               GPIO_Pin_11

#define SYS_SYNC_N_GPIO         GPIOC

#define SYS_SYNC_N_PIN          GPIO_Pin_12

#define SYS_PD_N_GPIO           GPIOC

#define SYS_PD_N_PIN            GPIO_Pin_13

#define SYS_WARMRST_N_GPIO      GPIOC

#define SYS_WARMRST_N_PIN       GPIO_Pin_14

#define BT_RST_GPIO             GPIOC

#define BT_RST_PIN              GPIO_Pin_15

#define OSC_IN_GPIO             GPIOD

#define OSC_IN_PIN              GPIO_Pin_0

#define OSC_OUT_GPIO            GPIOD

#define OSC_OUT_PIN             GPIO_Pin_1

#define CHARGE_EN2_N_GPIO       GPIOD

#define CHARGE_EN2_N_PIN        GPIO_Pin_2

#define HIBERNATE_TIME_MS       5000

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

* Function prototypes and static variables

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

static void Init(void);

static void initGpio();

static void initExti();

void configGpioForShutdown();

void systemPowerDown();

ErrorStatus handleColdReset();

ErrorStatus handleSoftwareReset();

ErrorStatus handleUartDnWakeup();

ErrorStatus handlePathDcWakeup();

ErrorStatus handleTouchWakeup();

ErrorStatus handleIwdgWakeup();

static void indicateHibernate();

static void AdcSingleMeasurement();

ADC_TypeDef* setupADC(ADC_TypeDef* adc, const uint16_t low_th, const uint16_t high_th);

uint16_t configIwdg(const uint16_t ms);

ErrorStatus shutdownDisambiguationProcedure(const uint8_t type);

void shutdownToTransportation();

void shutdownToDeepsleep();

void shutdownToHibernate();

void shutdownAndRestart();

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_Release, BL_VERSION_MAJOR, BL_VERSION_MINOR, 1},

  .vSSSP = {BL_VERSION_ID_SSSP, SSSP_VERSION_MAJOR, 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    none.

**

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

void main(void)

{

  /* initialize the microcontroller */

  Init();

  /* activate some required clocks */

  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA | RCC_AHB1Periph_GPIOB | RCC_AHB1Periph_GPIOC | RCC_AHB1Periph_GPIOD, ENABLE);

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE);

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);

  /* initialize GPIOs and EXTI lines */

  initGpio();

  setLed(BLT_TRUE);

  initExti();

  /* initialize the timer */

  TimerInit(); // do not use saTimerInit() in order to initialize the static variable.

  /* read the backup register */

  backup_reg.raw = RTC_ReadBackupRegister(BL_RTC_BACKUP_REG);

  /* 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)   |

      ((RCC_GetFlagStatus(RCC_FLAG_BORRST) == SET) ? BL_WAKEUP_PRI_RSN_BORRST : 0)   |

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

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

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

    if (GPIO_ReadInputDataBit(SYS_UART_DN_GPIO, SYS_UART_DN_PIN) == Bit_RESET) {

      backup_reg.wakeup_sec_reason = BL_WAKEUP_SEC_RSN_UART;

    } else if (GPIO_ReadInputDataBit(PATH_DC_GPIO, PATH_DC_PIN) == Bit_SET) {

      backup_reg.wakeup_sec_reason = BL_WAKEUP_SEC_RSN_PWRPLUG;

    } else {

      backup_reg.wakeup_sec_reason = BL_WAKEUP_SEC_RSN_TOUCH;

    }

  } else {

    backup_reg.wakeup_sec_reason = BL_WAKEUP_SEC_RSN_UNKNOWN;

  }

  /* store the information about this wakeup/restart in the backup register */

  PWR_BackupAccessCmd(ENABLE);

  RTC_WriteBackupRegister(BL_RTC_BACKUP_REG, backup_reg.raw);

  /* clear the flags */

  RCC_ClearFlag();

  PWR_ClearFlag(PWR_FLAG_WU);

  setLed(BLT_FALSE);

  /* handle different wakeup/reset reasons */

  ErrorStatus status = ERROR;

  if (backup_reg.wakeup_pri_reason & BL_WAKEUP_PRI_RSN_SFTRST) {

    /* system was reset by software */

    status = handleSoftwareReset();

  } else if (backup_reg.wakeup_pri_reason & BL_WAKEUP_PRI_RSN_WKUP) {

    /* system was woken via WKUP pin */

    /* differeciate between thre wakeup types */

    switch (backup_reg.wakeup_sec_reason) {

      case BL_WAKEUP_SEC_RSN_UART:

        status = handleUartDnWakeup();

        break;

      case BL_WAKEUP_SEC_RSN_PWRPLUG:

        status = handlePathDcWakeup();

        break;

      case BL_WAKEUP_SEC_RSN_TOUCH:

        status = handleTouchWakeup();

        break;

      default:

        status = ERROR;

        break;

    }

  } else if (backup_reg.wakeup_pri_reason & BL_WAKEUP_PRI_RSN_IWDGRST) {

    /* system was woken by IWDG */

    status = handleIwdgWakeup();

  } else if (backup_reg.wakeup_pri_reason == BL_WAKEUP_PRI_RSN_PINRST) {

    /* system was reset via NRST pin */

    status = handleColdReset();

  } else {

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

     * In this case the LED blinks "SOS" (... --- ...) and the system resets.

     */

    blinkSOS(1);

    status = ERROR;

    backup_reg.shutdown_pri_reason = BL_SHUTDOWN_PRI_RSN_RESTART;

    backup_reg.shutdown_sec_reason = BL_SHUTDOWN_SEC_RSN_UNKNOWN;

    RTC_WriteBackupRegister(BL_RTC_BACKUP_REG, backup_reg.raw);

    NVIC_SystemReset();

  }

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

  if (status != SUCCESS) {

    blinkSOSinf();

  }

  return;

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

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

** \brief     Initializes the microcontroller.

** \return    none.

**

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

static void Init(void)

{

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

  GPIO_InitTypeDef  GPIO_InitStructure;

#elif (BOOT_FILE_SYS_ENABLE > 0)

  GPIO_InitTypeDef  GPIO_InitStructure;

  USART_InitTypeDef USART_InitStructure;

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

  GPIO_InitTypeDef  GPIO_InitStructure;

#endif

  /* initialize the system and its clocks */

  SystemInit();

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

  /* enable UART peripheral clock */

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);

  /* enable GPIO peripheral clock for transmitter and receiver pins */

  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);

  /* connect the pin to the peripherals alternate function */

  GPIO_PinAFConfig(GPIOA, GPIO_PinSource9, GPIO_AF_USART1);

  GPIO_PinAFConfig(GPIOA, GPIO_PinSource10, GPIO_AF_USART1);

  /* configure USART Tx as alternate function  */

  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;

  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;

  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

  GPIO_Init(GPIOA, &GPIO_InitStructure);

  /* configure USART Rx as alternate function */

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;

  GPIO_Init(GPIOA, &GPIO_InitStructure);

#endif

#if (BOOT_COM_BLUETOOTH_UART_ENABLE > 0)

  /* enable UART peripheral clock */

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3, ENABLE);

  /* enable GPIO peripheral clock for transmitter and receiver pins */

  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC, ENABLE);

  /* connect the pin to the peripherals alternate function */

  GPIO_PinAFConfig(GPIOC, GPIO_PinSource10, GPIO_AF_USART3);

  GPIO_PinAFConfig(GPIOC, GPIO_PinSource11, GPIO_AF_USART3);

  /* configure USART Tx as alternate function  */

  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;

  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;

  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

  GPIO_Init(GPIOC, &GPIO_InitStructure);

  /* configure USART Rx as alternate function */

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;

  GPIO_Init(GPIOC, &GPIO_InitStructure);

  /* Configure Bluetooth reset pin */

  GPIO_InitTypeDef  gpio_init;

  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC, ENABLE);

  gpio_init.GPIO_Pin   = BT_RST_PIN;

  gpio_init.GPIO_OType = GPIO_OType_OD;

  gpio_init.GPIO_PuPd = GPIO_PuPd_NOPULL;

  gpio_init.GPIO_Mode = GPIO_Mode_OUT;

  gpio_init.GPIO_Speed = GPIO_Speed_50MHz;

  GPIO_Init(BT_RST_GPIO, &gpio_init);

  /* Reset Bluetooth reset pin */

  GPIO_ResetBits(BT_RST_GPIO, BT_RST_PIN);

#endif

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

  /* enable clocks for CAN transmitter and receiver pins */

  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);

  /* select alternate function for the CAN pins */

  GPIO_PinAFConfig(GPIOA, GPIO_PinSource11, GPIO_AF_CAN1);

  GPIO_PinAFConfig(GPIOA, GPIO_PinSource12, GPIO_AF_CAN1);

  /* configure CAN RX and TX pins */

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;

  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

  GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_AF;

  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;

  GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_NOPULL;

  GPIO_Init(GPIOA, &GPIO_InitStructure);

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12;

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;

  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;

  GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_NOPULL;

  GPIO_Init(GPIOA, &GPIO_InitStructure);

#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;

  gpio_init.GPIO_Speed  = GPIO_Speed_50MHz;

  gpio_init.GPIO_OType  = GPIO_OType_PP;

  gpio_init.GPIO_PuPd   = GPIO_PuPd_NOPULL;

  GPIO_Init(LED_GPIO, &gpio_init);

  /* initialize SYS_PD_N and push it up (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;

  gpio_init.GPIO_Speed  = GPIO_Speed_50MHz;

  gpio_init.GPIO_OType  = GPIO_OType_OD;

  gpio_init.GPIO_PuPd   = GPIO_PuPd_NOPULL;

  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;

  gpio_init.GPIO_Speed  = GPIO_Speed_50MHz;

  gpio_init.GPIO_OType  = GPIO_OType_OD;

  gpio_init.GPIO_PuPd   = GPIO_PuPd_NOPULL;

  GPIO_Init(SYS_SYNC_N_GPIO, &gpio_init);

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

  GPIO_ResetBits(SYS_WARMRST_N_GPIO, SYS_WARMRST_N_PIN);

  gpio_init.GPIO_Pin    = SYS_WARMRST_N_PIN;

  gpio_init.GPIO_Mode   = GPIO_Mode_OUT;

  gpio_init.GPIO_Speed  = GPIO_Speed_50MHz;

  gpio_init.GPIO_OType  = GPIO_OType_OD;

  gpio_init.GPIO_PuPd   = GPIO_PuPd_NOPULL;

  GPIO_Init(SYS_WARMRST_N_GPIO, &gpio_init);

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

  GPIO_SetBits(SYS_UART_DN_GPIO, SYS_UART_DN_PIN);

  gpio_init.GPIO_Pin    = SYS_UART_DN_PIN;

  gpio_init.GPIO_Mode   = GPIO_Mode_OUT;

  gpio_init.GPIO_Speed  = GPIO_Speed_50MHz;

  gpio_init.GPIO_OType  = GPIO_OType_OD;

  gpio_init.GPIO_PuPd   = GPIO_PuPd_NOPULL;

  GPIO_Init(SYS_UART_DN_GPIO, &gpio_init);

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

  GPIO_ResetBits(POWER_EN_GPIO, POWER_EN_PIN);

  gpio_init.GPIO_Pin    = POWER_EN_PIN;

  gpio_init.GPIO_Mode   = GPIO_Mode_OUT;

  gpio_init.GPIO_Speed  = GPIO_Speed_50MHz;

  gpio_init.GPIO_OType  = GPIO_OType_PP;

  gpio_init.GPIO_PuPd   = GPIO_PuPd_NOPULL;

  GPIO_Init(POWER_EN_GPIO, &gpio_init);

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

  GPIO_ResetBits(SYS_REG_EN_GPIO, SYS_REG_EN_PIN);

  gpio_init.GPIO_Pin    = SYS_REG_EN_PIN;

  gpio_init.GPIO_Mode   = GPIO_Mode_OUT;

  gpio_init.GPIO_Speed  = GPIO_Speed_50MHz;

  gpio_init.GPIO_OType  = GPIO_OType_PP;

  gpio_init.GPIO_PuPd   = GPIO_PuPd_NOPULL;

  GPIO_Init(SYS_REG_EN_GPIO, &gpio_init);

  /* initialize CHARGE_EN1_N and CHARGE_EN2_N and push them up (inactive) */

  GPIO_SetBits(CHARGE_EN1_N_GPIO, CHARGE_EN1_N_PIN);

  GPIO_SetBits(CHARGE_EN2_N_GPIO, CHARGE_EN2_N_PIN);

  gpio_init.GPIO_Pin    = CHARGE_EN1_N_PIN;

  gpio_init.GPIO_Mode   = GPIO_Mode_OUT;

  gpio_init.GPIO_Speed  = GPIO_Speed_50MHz;

  gpio_init.GPIO_OType  = GPIO_OType_PP;

  gpio_init.GPIO_PuPd   = GPIO_PuPd_NOPULL;

  GPIO_Init(CHARGE_EN1_N_GPIO, &gpio_init);

  gpio_init.GPIO_Pin    = CHARGE_EN2_N_PIN;

  GPIO_Init(CHARGE_EN2_N_GPIO, &gpio_init);

  /*

   * INPUTS

   */

  /* initialize PATH_DC */

  gpio_init.GPIO_Pin    = PATH_DC_PIN;

  gpio_init.GPIO_Mode   = GPIO_Mode_IN;

  gpio_init.GPIO_Speed  = GPIO_Speed_50MHz;

  gpio_init.GPIO_OType  = GPIO_OType_PP;

  gpio_init.GPIO_PuPd   = GPIO_PuPd_NOPULL;

  GPIO_Init(PATH_DC_GPIO, &gpio_init);

  /* initialize TOUCH_INT_N */

  gpio_init.GPIO_Pin    = TOUCH_INT_N_PIN;

  gpio_init.GPIO_Mode   = GPIO_Mode_IN;

  gpio_init.GPIO_Speed  = GPIO_Speed_50MHz;

  gpio_init.GPIO_OType  = GPIO_OType_PP;

  gpio_init.GPIO_PuPd   = GPIO_PuPd_NOPULL;

  GPIO_Init(TOUCH_INT_N_GPIO, &gpio_init);

  /* initialize VSYS_SENSE as analog input */

  gpio_init.GPIO_Pin    = VSYS_SENSE_PIN;

  gpio_init.GPIO_Mode   = GPIO_Mode_AN;

  gpio_init.GPIO_Speed  = GPIO_Speed_50MHz;

  gpio_init.GPIO_OType  = GPIO_OType_PP;

  gpio_init.GPIO_PuPd   = GPIO_PuPd_NOPULL;

  GPIO_Init(VSYS_SENSE_GPIO, &gpio_init);

  /* initialize GPIOB4, since it is configured in alternate function mode on reset */

  gpio_init.GPIO_Pin    = CHARGE_STAT2A_PIN;

  gpio_init.GPIO_Mode   = GPIO_Mode_IN;

  gpio_init.GPIO_Speed  = GPIO_Speed_50MHz;

  gpio_init.GPIO_OType  = GPIO_OType_PP;

  gpio_init.GPIO_PuPd   = GPIO_PuPd_NOPULL;

  GPIO_Init(CHARGE_STAT2A_GPIO, &gpio_init);

  return;

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

/*

 * Initialize all EXTI lines

 */

static void initExti() {

  /* configure EXTI lines */

  SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOB, EXTI_PinSource0); // IR_INT1_N

  SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOC, EXTI_PinSource0); // CHARGE_STAT1A

  SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOC, EXTI_PinSource1); // GAUGE_BATLOW1

  SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOC, EXTI_PinSource2); // GAUGE_BATGD1_N

  SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOB, EXTI_PinSource3); // SYS_UART_DN

  SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOB, EXTI_PinSource4); // CHARGE_STAT2A

  SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOC, EXTI_PinSource4); // IR_INT2_N

  SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOC, EXTI_PinSource5); // TOUCH_INT_N

  SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOB, EXTI_PinSource6); // GAUGE_BATLOW2

  SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOB, EXTI_PinSource7); // GAUGE_BATGD2_N

  SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOC, EXTI_PinSource8); // PATH_DC

  SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOC, EXTI_PinSource9); // SYS_SPI_DIR

  SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOC, EXTI_PinSource12); // SYS_SYNC_N

  SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOC, EXTI_PinSource13); // SYS_PD_N

  SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOC, EXTI_PinSource14); // SYS_WARMRST_N

  SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOB, EXTI_PinSource15); // SYS_UART_UP

  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() {

  /* configure some criticpal GPIOs as input

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

  configGpioForShutdown();

  /* power down the system */

  systemPowerDown();

  /* deactivate the WKUP pin */

  PWR_WakeUpPinCmd(DISABLE);

  /* deactivate any RTC related events */

  RTC_WakeUpCmd(DISABLE);

  RTC_TamperCmd(RTC_Tamper_1, DISABLE);

  RTC_TimeStampCmd(RTC_TimeStampEdge_Rising, DISABLE);

  RTC_TimeStampCmd(RTC_TimeStampEdge_Falling, DISABLE);

  RTC_ClearFlag(~0);

  /* disable the IWDG */

  IWDG_ReloadCounter();

  /* write some information to the backup register */

  blBackupRegister_t backup;

  backup.shutdown_pri_reason = BL_SHUTDOWN_PRI_RSN_TRANSPORT;

  backup.shutdown_sec_reason = BL_SHUTDOWN_SEC_RSN_UNKNOWN;

  backup.wakeup_pri_reason = BL_WAKEUP_PRI_RSN_UNKNOWN;

  backup.wakeup_sec_reason = BL_WAKEUP_SEC_RSN_UNKNOWN;

  PWR_BackupAccessCmd(ENABLE);

  RTC_WriteBackupRegister(BL_RTC_BACKUP_REG, backup.raw);

  /* 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 deepseleep mode.

 */

void shutdownToDeepsleep() {

  /* configure some criticpal GPIOs as input

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

  configGpioForShutdown();

  /* power down the system */

  systemPowerDown();

  /* activate the WKUP pin */

  PWR_WakeUpPinCmd(ENABLE);

  /*

   * Configuration of RTC and IWDG belongs to the OS.

   */

  /* write some information to the backup register */

  blBackupRegister_t backup;

  backup.shutdown_pri_reason = BL_SHUTDOWN_PRI_RSN_DEEPSLEEP;

  backup.shutdown_sec_reason = BL_SHUTDOWN_SEC_RSN_UNKNOWN;

  backup.wakeup_pri_reason = BL_WAKEUP_PRI_RSN_UNKNOWN;

  backup.wakeup_sec_reason = BL_WAKEUP_SEC_RSN_UNKNOWN;

  PWR_BackupAccessCmd(ENABLE);

  RTC_WriteBackupRegister(BL_RTC_BACKUP_REG, backup.raw);

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

  blinkOK(1);

  /* enter standby mode or restart the system in case a power plug is already present */

  if (GPIO_ReadInputDataBit(PATH_DC_GPIO, PATH_DC_PIN) != Bit_SET) {

    PWR_EnterSTANDBYMode();

  } else {

    NVIC_SystemReset();

  }

  return;

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

/*

 * Final shutdown of the system to enter hibernate mode.

 */

void shutdownToHibernate() {

  /* configure some criticpal GPIOs as input

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

  configGpioForShutdown();

  /* power down the system */

  systemPowerDown();

  /* write some information to the backup register */

  blBackupRegister_t backup;

  backup.shutdown_pri_reason = BL_SHUTDOWN_PRI_RSN_HIBERNATE;

  backup.shutdown_sec_reason = BL_SHUTDOWN_SEC_RSN_UNKNOWN;

  backup.wakeup_pri_reason = BL_WAKEUP_PRI_RSN_UNKNOWN;

  backup.wakeup_sec_reason = BL_WAKEUP_SEC_RSN_UNKNOWN;

  PWR_BackupAccessCmd(ENABLE);

  RTC_WriteBackupRegister(BL_RTC_BACKUP_REG, backup.raw);

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

  blinkOK(1);

  /* reset the MCU */

  NVIC_SystemReset();

  return;

} /*** end of shutdownToHibernate ***/

/*

 * Final shutdown of the system and restart.

 */

void shutdownAndRestart() {

  /* configure some criticpal GPIOs as input

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

  configGpioForShutdown();

  /* power down the system */

  systemPowerDown();

  /* write some information to the backup register */

  blBackupRegister_t backup;

  backup.shutdown_pri_reason = BL_SHUTDOWN_PRI_RSN_RESTART;

  backup.shutdown_sec_reason = BL_SHUTDOWN_SEC_RSN_UNKNOWN;

  backup.wakeup_pri_reason = BL_WAKEUP_PRI_RSN_UNKNOWN;

  backup.wakeup_sec_reason = BL_WAKEUP_SEC_RSN_UNKNOWN;

  PWR_BackupAccessCmd(ENABLE);

  RTC_WriteBackupRegister(BL_RTC_BACKUP_REG, backup.raw);

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

  blinkOK(1);

  /* reset the MCU */

  NVIC_SystemReset();

  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;

  gpio_init.GPIO_Speed  = GPIO_Speed_50MHz;

  gpio_init.GPIO_OType  = GPIO_OType_PP;

  gpio_init.GPIO_PuPd   = GPIO_PuPd_NOPULL;

  /* configure SYS_UART_TX */

  gpio_init.GPIO_Pin = SYS_UART_TX_PIN;

  GPIO_Init(SYS_UART_TX_GPIO, &gpio_init);

  /* configure all SYS_SPI signals */

  gpio_init.GPIO_Pin = SYS_SPI_SS0_N_PIN;

  GPIO_Init(SYS_SPI_SS0_N_GPIO, &gpio_init);

  gpio_init.GPIO_Pin = SYS_SPI_SCLK_PIN;

  GPIO_Init(SYS_SPI_SCLK_GPIO, &gpio_init);

  gpio_init.GPIO_Pin = SYS_SPI_MISO_PIN;

  GPIO_Init(SYS_SPI_MISO_GPIO, &gpio_init);

  gpio_init.GPIO_Pin = SYS_SPI_MOSI_PIN;

  GPIO_Init(SYS_SPI_MOSI_GPIO, &gpio_init);

  gpio_init.GPIO_Pin = SYS_SPI_SS1_N_PIN;

  GPIO_Init(SYS_SPI_SS1_N_GPIO, &gpio_init);

  gpio_init.GPIO_Pin = SYS_SPI_DIR_PIN;

  GPIO_Init(SYS_SPI_DIR_GPIO, &gpio_init);

  /* configure CAN_TX */

  gpio_init.GPIO_Pin = CAN_TX_PIN;

  GPIO_Init(CAN_TX_GPIO, &gpio_init);

  /* configure all Bluetooth signals */

  gpio_init.GPIO_Pin = BT_CTS_PIN;

  GPIO_Init(BT_CTS_GPIO, &gpio_init);

  gpio_init.GPIO_Pin = BT_RX_PIN;

  GPIO_Init(BT_RX_GPIO, &gpio_init);

  return;

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

/*

 * Disables all regulated voltages and finally cuts power to the rest of the system.

 */

void systemPowerDown() {

  setLed(BLT_TRUE);

  /* make sure that all other modules are shut down */

  msleep(10);

  /* reset slave modules */

  GPIO_ResetBits(SYS_WARMRST_N_GPIO, SYS_WARMRST_N_PIN);

  /* disable voltage regulators */

  GPIO_ResetBits(SYS_REG_EN_GPIO, SYS_REG_EN_PIN);

  /* cut power */

  GPIO_ResetBits(POWER_EN_GPIO, POWER_EN_PIN);

  /* make sure, all capacitors are discharged */

  msleep(100);

  setLed(BLT_FALSE);

  return;

} /*** end of systemPowerDown ***/

/*

 * Cofigures the independent watchdog (IWDG) to fire after the specified time when it is enabled.

 * The argument is the requested time in milliseconds.

 * The time that was actually set for the IWDG is returned by the function (again in milliseconds).

 * In some cases the returned value might differ from the requested one, but if so, it will alwyas be smaller.

 * Although the IWDG provides higher resolutions than milliseconds, these are not supported by this function.

 */

uint16_t configIwdg(const uint16_t ms) {

  /* apply an upper bound to the ms argument */

  uint16_t ms_capped = (ms >= 0x8000) ? 0x7FFF : ms;

  /* detect the best fitting prescaler and compute the according reload value */

  uint8_t prescaler = 0;

  uint16_t reload_val = 0;

  if (ms_capped >= 0x4000) {

    prescaler = IWDG_Prescaler_256;

    reload_val = ms_capped >> 3;  // note: this corresponds to a floor function

    ms_capped = reload_val << 3;  // this applies the floor function to ms_capped

  } else if (ms_capped >= 0x2000) {

    prescaler = IWDG_Prescaler_128;

    reload_val = ms_capped >> 2;  // note: this corresponds to a floor function

    ms_capped = reload_val << 2;  // this applies the floor function to ms_capped

  } else if (ms_capped >= 0x1000) {

    ms_capped &= ~(0x0001);

    prescaler = IWDG_Prescaler_64;

    reload_val = ms_capped >> 1;  // note: this corresponds to a floor function

    ms_capped = reload_val << 1;  // this applies the floor function to ms_capped

  } else {

    prescaler = IWDG_Prescaler_32;

    reload_val = ms_capped;

  }

  /* configure the IWDG */

  if (reload_val > 0) {

    IWDG_WriteAccessCmd(IWDG_WriteAccess_Enable);

    IWDG_SetPrescaler(prescaler);

    IWDG_SetReload(reload_val);

    IWDG_WriteAccessCmd(IWDG_WriteAccess_Disable);

  }

  return ms_capped;

} /*** end of configIWDG ***/

/*

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

 * In this case, everything is started up.

 * If an attempt for an OS update is detected, flashing mode is entered.

 * Otherwise, the system will boot the OS.

 */

ErrorStatus handleColdReset() {

  /* activate system power and wait some time to ensure stable voltages */

  setLed(BLT_TRUE);

  GPIO_SetBits(POWER_EN_GPIO, POWER_EN_PIN);

  msleep(10);

  GPIO_SetBits(SYS_REG_EN_GPIO, SYS_REG_EN_PIN);

  msleep(10);

  setLed(BLT_FALSE);

  /* drive SYS_WARMRST_N high (inactive) */

  GPIO_SetBits(SYS_WARMRST_N_GPIO, SYS_WARMRST_N_PIN);

  /* enable CAN clock

   * Note that CAN1 shares reception filters with CAN1 so for CAN2 the CAN1 peripheral also needs to be enabled. */

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_CAN2 | RCC_APB1Periph_CAN1, ENABLE);

  /* wait 1ms to make sure that all modules are running and started the bootloader */

  msleep(1);

  /* 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;

    }

  }

  return ERROR;

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

/*

 * System was reset by software.

 * Depending on the argument, which was read from the 1st backup register (see main function) the effect of this function differs.

 * There are three cases that can occur:

 * - The system was reset to enter hibernate mode.

 *   In this case the system will enter a medium power saving mode (hibernate mode), but can be charged via the charging pins.

 *   The system can be woken up in the same way as in deepsleep mode (cf. blCallbackShutdownDeepsleep() function).

 * - The system was reset to reboot.

 *   In this case the system will restart in the same way as after a cold reset.

 * - The reason is unknown.

 *   This case will cause an error.

 */

ErrorStatus handleSoftwareReset() {

  /* action depends on original shutdown reason */

  switch (backup_reg.shutdown_pri_reason) {

    case BL_SHUTDOWN_PRI_RSN_HIBERNATE:

    {

      /* activate the WKUP pin */

      PWR_WakeUpPinCmd(ENABLE);

      /* deactivate any RTC related events */

      RTC_WakeUpCmd(DISABLE);

      RTC_TamperCmd(RTC_Tamper_1, DISABLE);

      RTC_TimeStampCmd(RTC_TimeStampEdge_Rising, DISABLE);

      RTC_TimeStampCmd(RTC_TimeStampEdge_Falling, DISABLE);

      /* configure the IWDG to wake the system from standby mode */

      uint16_t iwdg_ms = 1;

      if (GPIO_ReadInputDataBit(PATH_DC_GPIO, PATH_DC_PIN) != Bit_SET) {

        /* if a power plug is detected, fire immediately (1ms), else fire after the defined hibernate time */

        iwdg_ms = HIBERNATE_TIME_MS;

      }

      configIwdg(iwdg_ms);

      IWDG_Enable();

      /* enter standby mode */

      PWR_EnterSTANDBYMode();

      return SUCCESS;

      break;

    }

    case BL_SHUTDOWN_PRI_RSN_RESTART:

    {

      return handleColdReset();

      break;

    }

    case BL_SHUTDOWN_PRI_RSN_DEEPSLEEP:

    {

      if (GPIO_ReadInputDataBit(PATH_DC_GPIO, PATH_DC_PIN) == Bit_SET) {

        return handlePathDcWakeup();

      } else {

        blCallbackShutdownDeepsleep();

      }

      break;

    }

    default:

      return ERROR;

  }

  return ERROR;

} /*** end of handleSoftwareReset ***/

/*

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

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

 * this function is identical to handleTouchWakeup().

 */

ErrorStatus handleUartDnWakeup() {

  return handleColdReset();

} /*** end of hanldeUartDnWakeup ***/

/*

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

 * If the system was woken from deepsleep mode, it will enter hibernate mode to enable charging as long as the power plug is present.

 * In any other case, the system will just enter the previous low-power mode again.

 */

ErrorStatus handlePathDcWakeup() {

  /* reenter the previous low-power mode */

  switch (backup_reg.shutdown_pri_reason) {

    case BL_SHUTDOWN_PRI_RSN_HIBERNATE:

      blCallbackShutdownHibernate();

      return SUCCESS;

      break;

    case BL_SHUTDOWN_PRI_RSN_DEEPSLEEP:

      /* visualize that the power plug was detected

       * This is helpful for feedback, and required for the follwing reason:

       * When the power plug is detected, it takes some additional time for the ADC to detect a high voltage.

       * If the ADC detects a low voltage at the first attempt, the system will enter hibernate mode.

       * Thus, the ADC will measure the voltage again after several seconds and charging will start.

       * However, this behaviour does not meet the user expection.

       * Hence, the voltage has some to adapt at this point

       */

      setLed(BLT_TRUE);

      msleep(500);

      setLed(BLT_FALSE);

      return handleIwdgWakeup();

      break;

    case BL_SHUTDOWN_PRI_RSN_TRANSPORT:

      blCallbackShutdownTransportation();

      return SUCCESS;

      break;

    default:

      return ERROR;

      break;

  }

  return ERROR;

} /*** end of handlePathDcWakeup ***/

/*

 * System was woken up via the WKUP pin and the touch sensors were found to be responsible.

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

 * This function is identical to handleUartDnWakeup().

 */

ErrorStatus handleTouchWakeup() {

  return handleColdReset();

} /*** end of handleTouchWakeup ***/

/*

 * System was woken up via the IWDG.

 * In this case the ADC is configured and VSYS is measured once.

 * If VSYS is found to be high enough to charge the batteries, the system will stay active until VSYS drops or an EXTI event occurs.

 * Otherwise, the system will configure the IWDG to wake the system again after five seconds and enter standby mode.

 */

ErrorStatus handleIwdgWakeup() {

  /* handle different situations, depending on the backup data */

  if ((backup_reg.shutdown_pri_reason == BL_SHUTDOWN_PRI_RSN_HIBERNATE) ||

      (backup_reg.shutdown_pri_reason == BL_SHUTDOWN_PRI_RSN_DEEPSLEEP)) {

    /* handle periodic wakeup in hibernate mode and in deepsleep mode when a power plug was detetced */

    /* if in hibernate mode, indicate the DiWheelDrive to enter hibernate mode as well, so it will activate the charging pins */

    if (backup_reg.shutdown_pri_reason == BL_SHUTDOWN_PRI_RSN_HIBERNATE) {

      indicateHibernate();

    }

    /* measure the current voltage of VSYS */

    AdcSingleMeasurement();

    /* evaluate the value

     * The ADC value represents the analog voltage between Vref- (= GND = 0.0V) and Vref+ (= VDD = 3.3V) as 12-bit value.

     * Hence, the value read from the register is first scaled to [0V .. 3.3V].

     * Then, an additional factor 5.33 is applied to account the downscaling on the board.

     * Actually, the factor should be 5.0, but due to too large resistors it was corrected to 5.33.

     */

    if ( (((float)(ADC_GetConversionValue(ADC1)) / (float)(0x0FFF)) * 3.3f * 5.33f) < 9.0f ) {

      /* VSYS was found to be < 9V */

      /* re-enter power saving mode

       * If the system was shut down to deepsleep mode and the power plug was removed, re-enter deepsleep mode.

       * (This could be done earlier in this function, but since charging via the pins of the DeWheelDrive may be

       *  supported in the future, this is done after measuring VSYS)

       */

      if (backup_reg.shutdown_pri_reason == BL_SHUTDOWN_PRI_RSN_DEEPSLEEP &&

          GPIO_ReadInputDataBit(PATH_DC_GPIO, PATH_DC_PIN) == Bit_RESET) {

        blCallbackShutdownDeepsleep();

      } else {

        /* reconfigure the IWDG and power down for five seconds */

        configIwdg(HIBERNATE_TIME_MS);

        IWDG_Enable();

        /* enter standby mode */

        PWR_EnterSTANDBYMode();

      }

      return SUCCESS;

    } else {

      /* VSYS was found to be >= 9V */

      setLed(BLT_TRUE);

      /* charge the battieries */

      GPIO_ResetBits(CHARGE_EN1_N_GPIO, CHARGE_EN1_N_PIN);

      GPIO_ResetBits(CHARGE_EN2_N_GPIO, CHARGE_EN2_N_PIN);

      /* configure analog watchdoch to fire as soon as the voltage drops below 9V */

      ADC_DeInit();

      setupADC(ADC1, (uint16_t)(9.0f / 5.33f / 3.3f * (float)0x0FFF), 0x0FFF);

      EXTI_InitTypeDef exti;

      /* configure UART_DN EXTI */

      exti.EXTI_Line = EXTI_Line3;

      exti.EXTI_Mode = EXTI_Mode_Interrupt;

      exti.EXTI_Trigger = EXTI_Trigger_Falling;

      exti.EXTI_LineCmd = ENABLE;

      EXTI_Init(&exti);

      /* configure TOUCH_INT_N EXTI */

      exti.EXTI_Line = EXTI_Line5;

      exti.EXTI_Mode = EXTI_Mode_Interrupt;

      exti.EXTI_Trigger = EXTI_Trigger_Falling;

      exti.EXTI_LineCmd = ENABLE;

      EXTI_Init(&exti);

      /* configure PATH_DC EXTI */

      if (backup_reg.shutdown_pri_reason == BL_SHUTDOWN_PRI_RSN_DEEPSLEEP) {

        exti.EXTI_Line = EXTI_Line8;

        exti.EXTI_Mode = EXTI_Mode_Interrupt;

        exti.EXTI_Trigger = EXTI_Trigger_Falling;

        exti.EXTI_LineCmd = ENABLE;

        EXTI_Init(&exti);

      }

      /* configure the NVIC so ADC and EXTI will be handled */

      NVIC_InitTypeDef nvic;

      nvic.NVIC_IRQChannel = ADC_IRQn;

      nvic.NVIC_IRQChannelPreemptionPriority = 6;

      nvic.NVIC_IRQChannelSubPriority = 6;

      nvic.NVIC_IRQChannelCmd = ENABLE;

      NVIC_Init(&nvic);

      nvic.NVIC_IRQChannel = EXTI3_IRQn;

      nvic.NVIC_IRQChannelPreemptionPriority = 6;

      nvic.NVIC_IRQChannelSubPriority = 6;

      nvic.NVIC_IRQChannelCmd = ENABLE;

      NVIC_Init(&nvic);

      NVIC_EnableIRQ(EXTI3_IRQn);

      nvic.NVIC_IRQChannel = EXTI9_5_IRQn;

      nvic.NVIC_IRQChannelPreemptionPriority = 6;

      nvic.NVIC_IRQChannelSubPriority = 6;

      nvic.NVIC_IRQChannelCmd = ENABLE;

      NVIC_Init(&nvic);

      NVIC_EnableIRQ(EXTI9_5_IRQn);

      /* activate the ADC */

      ADC_SoftwareStartConv(ADC1);

      /* sleep until something happens */

      __WFI();

      /* disable the chargers */

      GPIO_SetBits(CHARGE_EN1_N_GPIO, CHARGE_EN1_N_PIN);

      GPIO_SetBits(CHARGE_EN2_N_GPIO, CHARGE_EN2_N_PIN);

      setLed(BLT_FALSE);

      /* evaluate wakeup reason */

      // note: since I (tschoepp) don't know the difference between 'pending' and 'active' IRQs, both flags are ORed.

      uint8_t wkup_rsn = BL_WAKEUP_SEC_RSN_UNKNOWN;

      if ((NVIC_GetActive(ADC_IRQn) != 0 || NVIC_GetPendingIRQ(ADC_IRQn) != 0) &&

          ADC_GetITStatus(ADC1, ADC_IT_AWD) == SET &&

          ADC_GetFlagStatus(ADC1, ADC_FLAG_AWD) == SET) {

        wkup_rsn |= BL_WAKEUP_SEC_RSN_VSYSLOW;

      }

      if ((NVIC_GetActive(EXTI3_IRQn) != 0 || NVIC_GetPendingIRQ(EXTI3_IRQn) != 0) &&

          EXTI_GetFlagStatus(EXTI_Line3) == SET) {

        wkup_rsn |= BL_WAKEUP_SEC_RSN_UART;

      }

      if ((NVIC_GetActive(EXTI9_5_IRQn) != 0 || NVIC_GetPendingIRQ(EXTI9_5_IRQn) != 0) &&

          EXTI_GetFlagStatus(EXTI_Line5) == SET) {

        wkup_rsn |= BL_WAKEUP_SEC_RSN_TOUCH;

      }

      if ((NVIC_GetActive(EXTI9_5_IRQn) != 0 || NVIC_GetPendingIRQ(EXTI9_5_IRQn) != 0) &&

          EXTI_GetFlagStatus(EXTI_Line8) == SET) {

        wkup_rsn |= BL_WAKEUP_SEC_RSN_PWRPLUG;

      }

      /* since only the first interrupt will be handles, clear any pending ones */

      NVIC_DisableIRQ(ADC_IRQn);

      NVIC_DisableIRQ(EXTI3_IRQn);

      NVIC_DisableIRQ(EXTI9_5_IRQn);

      NVIC_ClearPendingIRQ(ADC_IRQn);

      NVIC_ClearPendingIRQ(EXTI3_IRQn);

      NVIC_ClearPendingIRQ(EXTI9_5_IRQn);

      /* clear all pending EXTI events */

      EXTI_DeInit();

      EXTI_ClearFlag(EXTI_Line3);

      EXTI_ClearFlag(EXTI_Line5);

      EXTI_ClearFlag(EXTI_Line8);

      /* make sure the LED was visibly turned off */

      msleep(100);

      /* depending on the wakup reason, handle accordingly */

      if (wkup_rsn & BL_WAKEUP_SEC_RSN_TOUCH) {

        /* the system was interrupted via the TOUCH_INT_N signal */

        /* act as if this was a normal touch wakeup */

        backup_reg.wakeup_pri_reason = BL_WAKEUP_PRI_RSN_WKUP;

        backup_reg.wakeup_sec_reason = BL_WAKEUP_SEC_RSN_TOUCH;

        RTC_WriteBackupRegister(BL_RTC_BACKUP_REG, backup_reg.raw);

        return handleTouchWakeup();

      } else if (wkup_rsn & BL_WAKEUP_SEC_RSN_UART) {

        /* the system was interrupted via the SYS_UARTDN signal */

        /* act as if this was a normal UART wakeup */

        backup_reg.wakeup_pri_reason = BL_WAKEUP_PRI_RSN_WKUP;

        backup_reg.wakeup_sec_reason = BL_WAKEUP_SEC_RSN_UART;

        RTC_WriteBackupRegister(BL_RTC_BACKUP_REG, backup_reg.raw);

        return handleUartDnWakeup();

      } else if (wkup_rsn & BL_WAKEUP_SEC_RSN_VSYSLOW) {

        /* VSYS has dropped below 9V */

        /* depending on the original reason for shutdown, act differenty */

        switch (backup_reg.shutdown_pri_reason) {

          case BL_SHUTDOWN_PRI_RSN_HIBERNATE:

          {

            blCallbackShutdownHibernate();

            return SUCCESS;

          }

          case BL_SHUTDOWN_PRI_RSN_DEEPSLEEP:

          {

            NVIC_SystemReset();

            return SUCCESS;

          }

          default:

            return ERROR;

        }

      } else if (wkup_rsn & BL_WAKEUP_SEC_RSN_PWRPLUG) {

        /* system was interrupted because the power plug was removed

         * note: when a power cord is plugged in, this will not trigger an interrupt because the NVIC is configured for a falling edge only */

        if (backup_reg.shutdown_pri_reason == BL_SHUTDOWN_PRI_RSN_DEEPSLEEP) {

          blCallbackShutdownDeepsleep();

          return SUCCESS;

        } else {

          /* this state is undefined, because the PATH_DC inerrupt is only configured when the primary shutdown reason was to enter deepsleep mode */

          return ERROR;

        }

      } else {

        /* the system was interrupted for an unknown reason */

        return ERROR;

      }

    } // end of ADC evaluation

  } else {

    /* since it is unknown why the IWDG was configured, act as after a cold reset */

    return handleColdReset();

  }

  return ERROR;

} /*** end of handleIwdgWakeup ***/

/*

 * Indicates the DiWheelDrive module to enter hibernate mode at wakeup.

 * This function should be called quite at the beginning of the according handleXXXReset/Wakeup() methods.

 */

static void indicateHibernate() {

  /* signal the DiWheelDrive to enter hibernate mode as well, so it will activate the charging pins */

  GPIO_ResetBits(SYS_UART_DN_GPIO, SYS_UART_DN_PIN);

  msleep(10); // this must be that long, because the DiWheelDrive sleeps some time before evaluating any signals

  GPIO_SetBits(SYS_UART_DN_GPIO, SYS_UART_DN_PIN);

  /* if the DiWheeDrive needs some time for setup it may pull down the signal */

  waitForSignal(SYS_UART_DN_GPIO, SYS_UART_DN_PIN, Bit_SET);

  return;

} /*** end of indicateHibernate ***/

/*

 *Performs a one-shot measurement of the VSYS voltage.

 */

static void AdcSingleMeasurement() {

  /* reset and initialize ADC for single-shot measurement */

//    ADC_DeInit();

  setupADC(ADC1, 0, 0);

  /* initialize the NVIC so ADC interrupts are handled */

  NVIC_InitTypeDef nvic;

  nvic.NVIC_IRQChannel = ADC_IRQn;

  nvic.NVIC_IRQChannelPreemptionPriority = 6;

  nvic.NVIC_IRQChannelSubPriority = 6;

  nvic.NVIC_IRQChannelCmd = ENABLE;

  NVIC_Init(&nvic);

  /* measure the voltage once */

  setLed(BLT_TRUE);

  ADC_ClearITPendingBit(ADC1, ADC_IT_EOC);

  ADC_ClearFlag(ADC1, ADC_FLAG_EOC);

  NVIC_EnableIRQ(ADC_IRQn);

  ADC_SoftwareStartConv(ADC1);

  while (ADC_GetITStatus(ADC1, ADC_IT_EOC) != SET && ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC) != SET) {

    __WFI();

  }

  NVIC_DisableIRQ(ADC_IRQn);

  ADC_ClearITPendingBit(ADC1, ADC_IT_EOC);

  ADC_ClearFlag(ADC1, ADC_FLAG_EOC);

  NVIC_ClearPendingIRQ(ADC_IRQn);

  setLed(BLT_FALSE);

  return;

} /*** end of AdcSingleMeasurement ***/

/*

 * Configures the ADC for measuring VSYS.

 * ADCx is the ADC object to initialize.

 * low_th and high_th are the threshold values for the analog watchdor (must be 12-bit!).

 * If low_th >= high_th, the ADC is configured for single-shot measurements.

 * Otherwise, the watchdog is configured with the corresponding thresholds.

 */

ADC_TypeDef* setupADC(ADC_TypeDef* adc, const uint16_t low_th, const uint16_t high_th) {

  /* evaluate the arguments */

  blt_bool awd_enable = BLT_FALSE;

  if (low_th < high_th) {

    awd_enable = BLT_TRUE;

  }

  /* enable the clock */

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);

  /* enable the ADC (wakes it from low-power mode) */

  ADC_Cmd(adc, ENABLE);

  /* initialize the common registers */

  ADC_CommonInitTypeDef adc_cinit;

  ADC_CommonStructInit(&adc_cinit);

  adc_cinit.ADC_Prescaler = ADC_Prescaler_Div8; // clock as slow as possible

  ADC_CommonInit(&adc_cinit);

  /* initialize the ADC */

  ADC_InitTypeDef adc_init;

  ADC_StructInit(&adc_init);

  adc_init.ADC_ContinuousConvMode = (awd_enable == BLT_TRUE) ? ENABLE : DISABLE;

  ADC_Init(adc, &adc_init);

  /* disable internal sensors */

  ADC_TempSensorVrefintCmd(DISABLE);

  ADC_VBATCmd(DISABLE);

  /* configure ADC channel and speed */

  ADC_RegularChannelConfig(adc, ADC_Channel_9, 1, ADC_SampleTime_480Cycles);

  ADC_EOCOnEachRegularChannelCmd(adc, (awd_enable == BLT_TRUE) ? DISABLE : ENABLE);

  ADC_DiscModeCmd(adc, DISABLE);

  /* disable DMA */

  ADC_DMACmd(adc, DISABLE);

  /* disable injected mode */

  ADC_AutoInjectedConvCmd(adc, DISABLE);

  ADC_InjectedDiscModeCmd(adc, DISABLE);

  /* configure the analog watchdog */

  if (awd_enable == BLT_TRUE) {

    ADC_AnalogWatchdogSingleChannelConfig(adc, ADC_Channel_9);

    ADC_AnalogWatchdogThresholdsConfig(adc, high_th, low_th);

    ADC_AnalogWatchdogCmd(adc, ADC_AnalogWatchdog_SingleRegEnable);

  } else {

    ADC_AnalogWatchdogCmd(adc, ADC_AnalogWatchdog_None);

  }

  /* configure the interrupts to be generated by the ADC */

  ADC_ITConfig(adc, ADC_IT_EOC, (awd_enable == BLT_TRUE) ? DISABLE : ENABLE);

  ADC_ITConfig(adc, ADC_IT_AWD, (awd_enable == BLT_TRUE) ? ENABLE : DISABLE);

  ADC_ITConfig(adc, ADC_IT_JEOC, DISABLE);

  ADC_ITConfig(adc, ADC_IT_OVR, DISABLE);

  return adc;

}

/*

 * 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_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA | RCC_AHB1Periph_GPIOB | RCC_AHB1Periph_GPIOC | RCC_AHB1Periph_GPIOD, ENABLE);

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, 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);

  /* initialized the standalone timer */

  saTimerInit();

  setLed(BLT_TRUE);

  /* 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);

  }

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

  if (shutdownDisambiguationProcedure(BL_SHUTDOWN_PRI_RSN_TRANSPORT) != SUCCESS) {

    blinkSOS(1);

    msleep(10);

  }

  shutdownToTransportation();

  return;

} /*** end of bLCallbackTransportation ***/

/*

 * 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.

 * When a power plug is detected, the system will switch to hibernate mode, to provide charging capabilities (cf. handlePathDcWakeup()).

 * As soon as the plug is removed again, however, the system will return to deppsleep mode (cf. handleIwdgWakeup()).

 */