AMiRo-OS

 * @brief   Flag to set the module to be the first in the stack.

 * @details There must be only one module with this flag set to true in a system.

 */

#if !defined(OS_CFG_SSSP_STACK_START)

  #define AMIROOS_CFG_SSSP_STACK_START          true

#else

  #define AMIROOS_CFG_SSSP_STACK_START          OS_CFG_SSSP_STACK_START

#endif

/**

 * @brief   Flag to set the module to be the last in the stack.

 * @details There must be only one module with this flag set to true in a system.

 */

#if !defined(OS_CFG_SSSP_STACK_END)

  #define AMIROOS_CFG_SSSP_STACK_END            false

#else

  #define AMIROOS_CFG_SSSP_STACK_END            OS_CFG_SSSP_STACK_END

#endif

/**

 * @brief   Delay time (in microseconds) how long a SSSP signal must be active.

 */

#if !defined(OS_CFG_SSSP_SIGNALDELAY)

  #define AMIROOS_CFG_SSSP_SIGNALDELAY          1000

#else

  #define AMIROOS_CFG_SSSP_SIGNALDELAY          OS_CFG_SSSP_SIGNALDELAY

#endif

/**

#if (AMIROOS_CFG_TESTS_ENABLE != true) && !defined(OS_CFG_SHELL_ENABLE)

 * PA12 - CAN_TX                    (alternate pushpull 50MHz)

                                     PIN_CR(GPIOA_CAN_TX, PIN_MODE_OUTPUT_50M, PIN_CNF_ALTERNATE_PUSHPULL) |       \

apalControlGpio_t moduleSsspGpioUp = {

  /* GPIO */ &moduleGpioSysUartUp,

  /* meta */ {

    /* active state */ APAL_GPIO_ACTIVE_LOW,

    /* edge         */ APAL_GPIO_EDGE_FALLING,

    /* direction    */ APAL_GPIO_DIRECTION_BIDIRECTIONAL,

  },

};

 * @brief   UP signal GPIO.

 */

extern apalControlGpio_t moduleSsspGpioUp;

/**

 * @brief   Event flags for SYNC signal events.

 * @brief   Event flags for UP signal events.

 */

#define MODULE_SSSP_EVENTFLAGS_UP               MODULE_OS_IOEVENTFLAGS_SYSUARTUP

/**

#define MODULE_SSSP_STARTUP_2_2_IOEVENT_HOOK(mask, flags) {                   \

 * @brief   Flag to set the module to be the first in the stack.

 * @details There must be only one module with this flag set to true in a system.

 */

#if !defined(OS_CFG_SSSP_STACK_START)

  #define AMIROOS_CFG_SSSP_STACK_START          false

#else

  #define AMIROOS_CFG_SSSP_STACK_START          OS_CFG_SSSP_STACK_START

#endif

/**

 * @brief   Flag to set the module to be the last in the stack.

 * @details There must be only one module with this flag set to true in a system.

 */

#if !defined(OS_CFG_SSSP_STACK_END)

  #define AMIROOS_CFG_SSSP_STACK_END            true

#else

  #define AMIROOS_CFG_SSSP_STACK_END            OS_CFG_SSSP_STACK_END

#endif

/**

 * @brief   Delay time (in microseconds) how long a SSSP signal must be active.

 */

#if !defined(OS_CFG_SSSP_SIGNALDELAY)

  #define AMIROOS_CFG_SSSP_SIGNALDELAY          1000

#else

  #define AMIROOS_CFG_SSSP_SIGNALDELAY          OS_CFG_SSSP_SIGNALDELAY

#endif

/**

#if (AMIROOS_CFG_TESTS_ENABLE != true) && !defined(OS_CFG_SHELL_ENABLE)

apalControlGpio_t moduleSsspGpioDn = {

  /* GPIO */ &moduleGpioSysUartDn,

  /* meta */ {

    /* active state */ APAL_GPIO_ACTIVE_LOW,

    /* edge         */ APAL_GPIO_EDGE_FALLING,

    /* direction    */ APAL_GPIO_DIRECTION_BIDIRECTIONAL,

  },

};

 * @brief   DN signal GPIO.

 */

extern apalControlGpio_t moduleSsspGpioDn;

/**

 * @brief   Event flags for SYNC signal events.

 * @brief   Event flags for DN signal events.

 */

#define MODULE_SSSP_EVENTFLAGS_DN               MODULE_OS_IOEVENTFLAGS_SYSUARTDN

/**

#define MODULE_SSSP_STARTUP_2_2_IOEVENT_HOOK(mask, flags) {                   \

 * @brief   Flag to set the module to be the first in the stack.

 * @details There must be only one module with this flag set to true in a system.

 */

#if !defined(OS_CFG_SSSP_STACK_START)

  #define AMIROOS_CFG_SSSP_STACK_START          false

#else

  #define AMIROOS_CFG_SSSP_STACK_START          OS_CFG_SSSP_STACK_START

#endif

/**

 * @brief   Flag to set the module to be the last in the stack.

 * @details There must be only one module with this flag set to true in a system.

 */

#if !defined(OS_CFG_SSSP_STACK_END)

  #define AMIROOS_CFG_SSSP_STACK_END            false

#else

  #define AMIROOS_CFG_SSSP_STACK_END            OS_CFG_SSSP_STACK_END

#endif

/**

 * @brief   Delay time (in microseconds) how long a SSSP signal must be active.

 */

#if !defined(OS_CFG_SSSP_SIGNALDELAY)

  #define AMIROOS_CFG_SSSP_SIGNALDELAY          1000

#else

  #define AMIROOS_CFG_SSSP_SIGNALDELAY          OS_CFG_SSSP_SIGNALDELAY

#endif

/**

#if (AMIROOS_CFG_TESTS_ENABLE != true) && !defined(OS_CFG_SHELL_ENABLE)

 * PA12 - CAN_TX                        (alternate 9 pushpull floating)

                                         PIN_MODE_ALTERNATE(GPIOA_CAN_TX) |                           \

  /* btr  */ CAN_BTR_SJW(1) | CAN_BTR_TS2(3) | CAN_BTR_TS1(15) | CAN_BTR_BRP(1),

apalControlGpio_t moduleSsspGpioDn = {

  /* GPIO */ &moduleGpioSysUartDn,

  /* meta */ {

    /* active state */ APAL_GPIO_ACTIVE_LOW,

    /* edge         */ APAL_GPIO_EDGE_FALLING,

    /* direction    */ APAL_GPIO_DIRECTION_BIDIRECTIONAL,

  },

};

apalControlGpio_t moduleSsspGpioUp = {

  /* GPIO */ &moduleGpioSysUartUp,

  /* meta */ {

    /* active state */ APAL_GPIO_ACTIVE_LOW,

    /* edge         */ APAL_GPIO_EDGE_FALLING,

    /* direction    */ APAL_GPIO_DIRECTION_BIDIRECTIONAL,

  },

};

 * @brief   DN signal GPIO.

 */

extern apalControlGpio_t moduleSsspGpioDn;

/**

 * @brief   UP signal GPIO.

 */

extern apalControlGpio_t moduleSsspGpioUp;

/**

 * @brief   Event flags for SYNC signal events.

 * @brief   Event flags for UP signal events.

 */

#define MODULE_SSSP_EVENTFLAGS_UP               MODULE_OS_IOEVENTFLAGS_SYSUARTUP

/**

 * @brief   Event flags for DN signal events.

 */

#define MODULE_SSSP_EVENTFLAGS_DN               MODULE_OS_IOEVENTFLAGS_SYSUARTDN

/**

#define MODULE_SSSP_STARTUP_2_2_IOEVENT_HOOK(mask, flags) {                   \

#ifndef AMIROOS_CFG_SSSP_STACK_START

  #error "AMIROOS_CFG_SSSP_STACK_START not defined in aosconf.h"

#endif

#ifndef AMIROOS_CFG_SSSP_STACK_END

  #error "AMIROOS_CFG_SSSP_STACK_END not defined in aosconf.h"

#endif

#if (AMIROOS_CFG_SSSP_STACK_START == true) && (AMIROOS_CFG_SSSP_STACK_END == true)

  #warning "AMIROOS_CFG_SSSP_STACK_START and AMIROOS_CFG_SSSP_STACK_END both enabled in aosconf.h"

  #if (AMIROOS_CFG_SSSP_MASTER != true)

    #error "AMIROOS_CFG_SSSP_MASTER must be enabled in this case"

  #endif

#endif

#ifndef AMIROOS_CFG_SSSP_SIGNALDELAY

  #error "AMIROOS_CFG_SSSP_SIGNALDELAY not defined in aosconf.h"

#endif

/**

 * @brief   Printf function for messages only printed in debug builds.

 *

 * @param[in] fmt   Formatted string to print.

 */

#define aosDbgPrintf(fmt, ...)           chprintf((BaseSequentialStream*)&aos.iostream, fmt, ##__VA_ARGS__)

#define aosDbgPrintf(fmt, ...) {                          \

  (void)(fmt);                                            \

}

#define AOS_SYSTEM_SSSP_VERSION_MAJOR           1

#define AOS_SYSTEM_SSSP_VERSION_MINOR           4

/**

 * @brief   Timeout delay according to SSSP.

 * @details SSSP defines timeouts to be ten times longer than the signal delay time.

 */

#define AOS_SYSTEM_SSSP_TIMEOUT                 (10 * AMIROOS_CFG_SSSP_SIGNALDELAY)

 * @brief   Enumerator of the several stages of SSSP.

  AOS_SSSP_STARTUP_1_1  = 0x10, /**< Identifier of SSSP startup phase stage 1-1. */

  AOS_SSSP_STARTUP_1_2  = 0x11, /**< Identifier of SSSP startup phase stage 1-2. */

  AOS_SSSP_STARTUP_1_3  = 0x12, /**< Identifier of SSSP startup phase stage 1-3. */

  AOS_SSSP_STARTUP_2_1  = 0x14, /**< Identifier of SSSP startup phase stage 2-1. */

  AOS_SSSP_STARTUP_2_2  = 0x15, /**< Identifier of SSSP startup phase stage 2-2. */

  AOS_SSSP_STARTUP_3_1  = 0x18, /**< Identifier of SSSP startup phase stage 3-1. */

  AOS_SSSP_STARTUP_3_2  = 0x19, /**< Identifier of SSSP startup phase stage 3-2. */

  AOS_SSSP_STARTUP_3_3  = 0x1A, /**< Identifier of SSSP startup phase stage 3-3. */

  AOS_SSSP_STARTUP_3_4  = 0x1B, /**< Identifier of SSSP startup phase stage 3-4. */

  AOS_SSSP_OPERATION    = 0x20, /**< Identifier of SSSP operation pahse. */

  AOS_SSSP_SHUTDOWN_1_1 = 0x30, /**< Identifier of SSSP shutdown phase stage 1-1. */

  AOS_SSSP_SHUTDOWN_1_2 = 0x31, /**< Identifier of SSSP shutdown phase stage 1-2. */

  AOS_SSSP_SHUTDOWN_1_3 = 0x32, /**< Identifier of SSSP shutdown phase stage 1-3. */

  AOS_SSSP_SHUTDOWN_2_1 = 0x34, /**< Identifier of SSSP shutdown phase stage 2-1. */

  AOS_SSSP_SHUTDOWN_2_2 = 0x35, /**< Identifier of SSSP shutdown phase stage 2-2. */

  AOS_SSSP_SHUTDOWN_3   = 0x38, /**< Identifier of SSSP shutdown phase stage 3. */

 * @brief   Type to represent module IDs.

 */

typedef uint16_t aos_ssspmoduleid_t;

/**

    /**

     * @brief   Module identifier.

     * @details A value of 0 indicates an uninitialized ID.

     *          The vlaues 0 and ~0 are reserved und must not be set.

     */

    aos_ssspmoduleid_t moduleId;

 *

 * @param[in] fmt   Formatted string to print.

 * @brief   Event mask to idetify CAN events.

 */

#define CANEVENT_MASK                           EVENT_MASK(2)

/**

 * @brief   Event mask to idetify timeout events.

 */

#define TIMEOUTEVENT_MASK                       EVENT_MASK(3)

/**

 * @brief   Event mask to idetify signal delay events.

 */

#define DELAYEVENT_MASK                         EVENT_MASK(4)

/**

 * @brief   CAN message identifier for initialization of the SSSP stack initialization sequence.

 */

#define SSSP_STACKINIT_CANMSGID_INIT            0x003

/**

 * @brief   CAN message identifier for transmitting module IDs during the SSSP stack initialization sequence.

 */

#define SSSP_STACKINIT_CANMSGID_MODULEID        0x002

/**

 * @brief   CAN message identifier for abortion of the SSSP stack initialization sequence.

 */

#define SSSP_STACKINIT_CANMSGID_ABORT           0x001

/**

static inline void _unexpectedEventError(const eventmask_t mask, const eventflags_t flags)

  (void)(mask);

  (void)(flags);

}

/**

 * @brief   Callback function to be used during SSSP stack initialization sequence.

 *

 * @param[in] par   A pointer to an @p event_source_t to be fired.

 */

static void _ssspTimerCallback(void* par)

{

  aosDbgCheck(par != NULL);

  chSysLockFromISR();

  chEvtBroadcastI((event_source_t*)par);

  chSysUnlockFromISR();

 * @brief   Helper function to serialize 32 bit data.

 *

 * @param[out]  dst   Pointer to the output buffer.

 * @param[in]   src   32 bit data to be serielized.

 */

inline void _canSerialize32(uint8_t* dst, const uint32_t src)

{

  aosDbgCheck(dst != NULL);

  for (uint8_t byte = 0; byte < 4; ++byte) {

    dst[byte] = (uint8_t)((src >> (byte * 8)) & 0xFF);

  }

  return;

}

/**

 * @brief   Helper function to deserialize 32 bit data.

 *

 * @param[in] src   Pointer to the buffer of data to be deserialzed.

 *

 * @return    The deserialized 32 bit data.

 */

inline uint32_t _canDeserialize32(uint8_t* src)

{

  aosDbgCheck(src != NULL);

  return ((uint32_t)src[0]) | (((uint32_t)src[1]) << 8) | (((uint32_t)src[2]) << 16) | (((uint32_t)src[3]) << 24);

}

/**

 * @brief   Implementation of the SSSP module stack initialization sequence (startup phase 3).

 *

 * @return Shutdown value.

 * @retval AOS_SHUTDOWN_NONE      No shutdown signal received

 * @retval AOS_SHUTDOWN_PASSIVE   Shutdown signal received.

 */

aos_shutdown_t _ssspModuleStackInitialization(void)

{

  // local types

  /**

   * @brief   States for the internal state machine to implement SSSP startup stage 3.

   */

  typedef enum {

    STAGE_3_1,                  /**< Initiation of SSSP startup stage 3. */

    STAGE_3_2,                  /**< Starting the sequence and broadcasting the first ID. */

    STAGE_3_3_WAITFORFIRSTID,   /**< Waiting for first ID after initiation. */

    STAGE_3_3_WAITFORIDORSIG,   /**< Waiting for next ID or activation of neighbor signal. */

    STAGE_3_3_WAITFORID,        /**< Waiting for next ID (after the module has set its own ID). */

    STAGE_3_4_FINISH,           /**< Successful finish of stage 3. */

    STAGE_3_4_ABORT_ACTIVE,     /**< Aborting stage 3 (active). */

    STAGE_3_4_ABORT,            /**< Aborting stage 3 (passive). */

  } sssp_modulestackinitstage_t;

  typedef struct {

    bool loop     : 1;

    bool wfe      : 1;

    bool wfe_next : 1;

  } flags_t;

  // local variables

  aos_shutdown_t shutdown = AOS_SHUTDOWN_NONE;

  sssp_modulestackinitstage_t stage = STAGE_3_1;

  eventmask_t eventmask = 0;

  eventflags_t ioflags;

  event_source_t eventSourceTimeout;

  event_source_t eventSourceDelay;

  event_listener_t eventListenerTimeout;

  event_listener_t eventListenerDelay;

  event_listener_t eventListenerCan;

  virtual_timer_t timerTimeout;

  virtual_timer_t timerDelay;

  CANTxFrame canTxFrame;

  CANRxFrame canRxFrame;

#if (AMIROOS_CFG_SSSP_STACK_START != true) || (AMIROOS_CFG_DBG == true)

  aos_ssspmoduleid_t lastid = 0;

#endif

  flags_t flags;

  // initialize local varibles

  chEvtObjectInit(&eventSourceTimeout);

  chEvtObjectInit(&eventSourceDelay);

  chVTObjectInit(&timerTimeout);

  chVTObjectInit(&timerDelay);

  canTxFrame.RTR = CAN_RTR_DATA;

  canTxFrame.IDE = CAN_IDE_STD;

  flags.loop = true;

  flags.wfe = false; // do not wait for events in the initial iteration of the FSM loop

  flags.wfe_next = true;

  // initialize system variables

  aos.sssp.stage = AOS_SSSP_STARTUP_3_1;

  aos.sssp.moduleId = 0;

  // listen to events (timout, delay, CAN receive)

  chEvtRegisterMask(&eventSourceTimeout, &eventListenerTimeout, TIMEOUTEVENT_MASK);

  chEvtRegisterMask(&eventSourceDelay, &eventListenerDelay, DELAYEVENT_MASK);

  chEvtRegisterMask(&MODULE_HAL_CAN.rxfull_event, &eventListenerCan, CANEVENT_MASK);

  /*

   * FSM in a loop.

   *

   * This is a fully event-based FSM for the module stack initialization

   * sequence, defined by SSSP as startup stage 3. There are five different

   * events that can occur at this point:

   *  I/O events: The input level of an input pin has changed. Such events must

   *              be handled differently depending on the current state. Most

   *              of the time, however, such events can be ignored.

   *  OS events:  Such events are only available after this stage completed and

   *              thus should never occur. However, there is an optional hook

   *              to handle such events, nevertheless.

   *  CAN events: At least one CAN message was received. Note that this event

   *              will only fire again if all input buffers have been cleared.

   *  timeouts:   If some module does not support the sequence of there is any

   *              issue, such a case is detected via timeouts and must be

   *              handled accordingly (see abort state). In some cases, it is

   *              possible that a timeout event occurres 'simultaneously' with

   *              some other event. This can be caused by several timing issues

   *              and is a valid situation. As a result, any other events

   *              should be handled before the timeout event. If the other

   *              events are expected and valid, this implementation requires

   *              the timeout event flag to be cleared explicitely. Otherwise

   *              it is evaluated at the end of each iteration of the loop.

   *  delays:     Depending on the current state, delays are required by SSSP

   *              for timing of the sequential activation of signals.

   */

  aosDbgPrintf("SSSP stack initialization sequence:\n");

  while (flags.loop) {

#if (AMIROOS_CFG_DBG == true)

    switch (stage) {

      case STAGE_3_1:

        aosDbgPrintf(">>> 3-1\n");

        break;

      case STAGE_3_2:

        aosDbgPrintf(">>> 3-2\n");

        break;

      case STAGE_3_3_WAITFORFIRSTID:

        aosDbgPrintf(">>> 3-3 (1st ID)\n");

        break;

      case STAGE_3_3_WAITFORIDORSIG:

        aosDbgPrintf(">>> 3-3 (ID/sig)\n");

        break;

      case STAGE_3_3_WAITFORID:

        aosDbgPrintf(">>> 3-3 (ID)\n");

        break;

      case STAGE_3_4_FINISH:

        aosDbgPrintf(">>> 3-4 (finish)\n");

        break;

      case STAGE_3_4_ABORT_ACTIVE:

        aosDbgPrintf(">>> 3-4 (avtive abort)\n");

        break;

      case STAGE_3_4_ABORT:

        aosDbgPrintf(">>> 3-4 (abort)\n");

        break;

    }

#endif

    // reset wfe flag for the next iteration

    flags.wfe_next = true;

    // waiting for events may be skipped

    if (flags.wfe) {

      // wait for any event to occur

      aosDbgPrintf("WFE...");

      eventmask = chEvtWaitAnyTimeout(ALL_EVENTS, LL_US2ST(AOS_SYSTEM_SSSP_TIMEOUT));

      aosDbgPrintf("\t0x%08X", eventmask);

    } else {

      aosDbgPrintf("WFE skipped");

    }

    aos_timestamp_t uptime;

    aosSysGetUptime(&uptime);

    aosDbgPrintf("\t%04ums\n", (uint32_t)(uptime / 1000));

    /*

     * execute some general tasks and high priority events

     */

    // no event occurred at all

    if ((flags.wfe) && (eventmask == 0)) {

      aosDbgPrintf("ERR: no evt\n");

      // enforce timeout event

      chEvtBroadcast(&eventSourceTimeout);

      continue;

    }

    // if an IO event occurred

    if (eventmask & IOEVENT_MASK) {

      ioflags = chEvtGetAndClearFlags(&_eventListenerIO);

      aosDbgPrintf("INFO: IO evt (0x%08X)\n", ioflags);

      // a power-down event occurred

      if (ioflags & MODULE_SSSP_EVENTFLAGS_PD) {

        aosDbgPrintf("PD evt\n");

        // deactivate S and UP

        apalControlGpioSet(&moduleSsspGpioSync, APAL_GPIO_OFF);

  #if (AMIROOS_CFG_SSSP_STACK_END != true)

        apalControlGpioSet(&moduleSsspGpioUp, APAL_GPIO_OFF);

  #endif

        // set shutdown flag and exit the loop

        shutdown = AOS_SHUTDOWN_PASSIVE;

        break;

      }

      // the S signal was deactivated

      if (ioflags & MODULE_SSSP_EVENTFLAGS_SYNC) {

        apalControlGpioState_t sstate;

        apalControlGpioGet(&moduleSsspGpioSync, &sstate);

        if (sstate == APAL_GPIO_OFF) {

          aosDbgPrintf("-S evt\n");

          // either finish or abort

          if ((stage == STAGE_3_3_WAITFORID) && (aos.sssp.moduleId != 0)) {

            stage = STAGE_3_4_FINISH;

          } else if (stage != STAGE_3_4_ABORT) {

            stage = STAGE_3_4_ABORT_ACTIVE;

          }

        }

      }

    }

    // an OS event occurred

    if (eventmask & OSEVENT_MASK) {

      aosDbgPrintf("WARN: OS evt\n");

      // get the flags

      eventflags_t oseventflags = chEvtGetAndClearFlags(&_eventListenerOS);

      // there should be no OS events at this point

#ifdef MODULE_SSSP_STARTUP_3_OSEVENT_HOOK

      MODULE_SSSP_STARTUP_3_OSEVENT_HOOK(eventmask, eventflags);

#else

      _unexpectedEventError(eventmask, oseventflags);

#endif

    }

    // if a CAN event occurred

    if ((eventmask & CANEVENT_MASK)) {

      // fetch message

      if (flags.wfe) {

        canReceiveTimeout(&MODULE_HAL_CAN, CAN_ANY_MAILBOX, &canRxFrame, TIME_IMMEDIATE);

        aosDbgPrintf("CAN <- 0x%03X\n", canRxFrame.SID);

      }

      // identify and handle abort messgaes

      if (canRxFrame.SID == SSSP_STACKINIT_CANMSGID_ABORT) {

        stage = STAGE_3_4_ABORT;

      }

      // warn if a unexpected message was received

      else if ((canRxFrame.SID != SSSP_STACKINIT_CANMSGID_INIT) &&

               (canRxFrame.SID != SSSP_STACKINIT_CANMSGID_MODULEID)) {

        aosDbgPrintf("WARN: unknown msg\n");

      }

      // any further pending messages are fetched at the end of the loop

    }

    // if a timeout event occurred

    if (eventmask & TIMEOUTEVENT_MASK) {

      // is handled at the end of the loop (or must be cleared by FSM)

    }

    // if a delay event occurred

    if (eventmask & DELAYEVENT_MASK) {

      // is handled by FSM

    }

    /*

     * this is the actual FSM

     */

    switch (stage) {

      case STAGE_3_1:

      {

        aos.sssp.stage = AOS_SSSP_STARTUP_3_1;

        // there was no event at all (skipped wfe)

        if (eventmask == 0 && flags.wfe == false) {

#if (AMIROOS_CFG_SSSP_MASTER == true)

          // initialize the stage by transmitting an according CAN message

          aosDbgPrintf("CAN -> init\n");

          canTxFrame.DLC = 0;

          canTxFrame.SID = SSSP_STACKINIT_CANMSGID_INIT;

          if (canTransmitTimeout(&MODULE_HAL_CAN, CAN_ANY_MAILBOX, &canTxFrame, TIME_IMMEDIATE) != MSG_OK) {

            chEvtBroadcast(&eventSourceTimeout);

            break;

          }

          // activate S

          aosDbgPrintf("S+\n");

          apalControlGpioSet(&moduleSsspGpioSync, APAL_GPIO_ON);

#if (AMIROOS_CFG_SSSP_STACK_START == true)

          // proceed immediately

          stage = STAGE_3_2;

          flags.wfe_next = false;

#else

          // set the timeout timer

          chVTSet(&timerTimeout, LL_US2ST(AOS_SYSTEM_SSSP_TIMEOUT), _ssspTimerCallback, &eventSourceTimeout);

          // proceed

          stage = STAGE_3_3_WAITFORFIRSTID;

#endif

#else

          // set the timeout timer

          chVTSet(&timerTimeout, LL_US2ST(AOS_SYSTEM_SSSP_TIMEOUT), _ssspTimerCallback, &eventSourceTimeout);

#endif

        }

#if (AMIROOS_CFG_SSSP_MASTER != true)

        // a CAN message was received

        else if (eventmask & CANEVENT_MASK) {

          // if an initiation message was received

          if (canRxFrame.DLC == 0 &&

              canRxFrame.RTR == CAN_RTR_DATA &&

              canRxFrame.IDE == CAN_IDE_STD &&

              canRxFrame.SID == SSSP_STACKINIT_CANMSGID_INIT) {

            aosDbgPrintf("init msg\n");

            // reset the timeout timer and clear pending flags

            chVTReset(&timerTimeout);

            chEvtWaitAnyTimeout(TIMEOUTEVENT_MASK, TIME_IMMEDIATE);

            eventmask &= ~TIMEOUTEVENT_MASK;

            // activate S

            aosDbgPrintf("S+\n");

            apalControlGpioSet(&moduleSsspGpioSync, APAL_GPIO_ON);

#if (AMIROOS_CFG_SSSP_STACK_START == true)

            // proceed

            stage = STAGE_3_2;

            flags.wfe_next = false;

#else

            // set the timeout timer

            chVTSet(&timerTimeout, LL_US2ST(AOS_SYSTEM_SSSP_TIMEOUT), _ssspTimerCallback, &eventSourceTimeout);

            // proceed

            stage = STAGE_3_3_WAITFORFIRSTID;

#endif

          }

        }

#endif

        break;

      } /* end of STAGE_3_1 */

      case STAGE_3_2:

      {

#if (AMIROOS_CFG_SSSP_STACK_START == true)

        aos.sssp.stage = AOS_SSSP_STARTUP_3_2;

        // if this stage was just entered

        if (flags.wfe == false) {

          // set the module ID

          aos.sssp.moduleId = 1;

          // broadcast module ID

          aosDbgPrintf("CAN -> ID (%u)\n", aos.sssp.moduleId);

          canTxFrame.DLC = 4;

          canTxFrame.SID = SSSP_STACKINIT_CANMSGID_MODULEID;

          _canSerialize32(canTxFrame.data8, aos.sssp.moduleId);

          if (canTransmitTimeout(&MODULE_HAL_CAN, CAN_ANY_MAILBOX, &canTxFrame, TIME_IMMEDIATE) != MSG_OK) {

            chEvtBroadcast(&eventSourceTimeout);

            break;

          }

#if (AMIROOS_CFG_SSSP_STACK_START != true) || (AMIROOS_CFG_DBG == true)

          lastid = aos.sssp.moduleId;

#endif

#if (AMIROOS_CFG_SSSP_STACK_END == true)

          // sequence is already over

          // deactivate S

          aosDbgPrintf("S-\n");

          apalControlGpioSet(&moduleSsspGpioSync, APAL_GPIO_OFF);

          // proceed

          stage = STAGE_3_3_WAITFORID;

#else

          // set the delay timer so the UP signal is activated later

          chVTSet(&timerDelay, LL_US2ST(AMIROOS_CFG_SSSP_SIGNALDELAY), _ssspTimerCallback, &eventSourceDelay);

#endif

        }

        // if a delay event occurred

        if (eventmask & DELAYEVENT_MASK) {

          // activate UP

          aosDbgPrintf("UP+\n");

          apalControlGpioSet(&moduleSsspGpioUp, APAL_GPIO_ON);

          // deactivate S

          aosDbgPrintf("S-\n");

          apalControlGpioSet(&moduleSsspGpioSync, APAL_GPIO_OFF);

          // explicitely clear timeout event flag

          chEvtWaitAnyTimeout(TIMEOUTEVENT_MASK, TIME_IMMEDIATE);

          eventmask &= ~TIMEOUTEVENT_MASK;

          // proceed

          stage = STAGE_3_3_WAITFORID;

        }

#endif

        break;

      } /* end of STAGE_3_2 */

      case STAGE_3_3_WAITFORFIRSTID:

      {

#if (AMIROOS_CFG_SSSP_STACK_START != true)

        aos.sssp.stage = AOS_SSSP_STARTUP_3_3;

        // a CAN message was received

        if (eventmask & CANEVENT_MASK) {

          // if an ID message was received

          if (canRxFrame.DLC == 4 &&

              canRxFrame.RTR == CAN_RTR_DATA &&

              canRxFrame.IDE == CAN_IDE_STD &&

              canRxFrame.SID == SSSP_STACKINIT_CANMSGID_MODULEID) {

            aosDbgPrintf("ID (%u)\n", _canDeserialize32(canRxFrame.data8));

            // validate received ID

            if (lastid < _canDeserialize32(canRxFrame.data8)) {

              // store received ID

              lastid = _canDeserialize32(canRxFrame.data8);

              // restart timeout timer

              chVTSet(&timerTimeout, LL_US2ST(AOS_SYSTEM_SSSP_TIMEOUT), _ssspTimerCallback, &eventSourceTimeout);

              // proceed

              stage = STAGE_3_3_WAITFORIDORSIG;

            } else {

              aosDbgPrintf("ERR: invalid ID\n");

              // abort

              stage = STAGE_3_4_ABORT_ACTIVE;

              flags.wfe_next = false;

            }

            // explicitely clear timeout event flag

            chEvtWaitAnyTimeout(TIMEOUTEVENT_MASK, TIME_IMMEDIATE);

            eventmask &= ~TIMEOUTEVENT_MASK;

          }

        }

#endif

        break;

      } /* end of STAGE_3_3_WAITFORFIRSTID */

      case STAGE_3_3_WAITFORIDORSIG:

      {

#if (AMIROOS_CFG_SSSP_STACK_START != true)

        aos.sssp.stage = AOS_SSSP_STARTUP_3_3;

        // a CAN message was received

        if (eventmask & CANEVENT_MASK) {

          // if an ID message was received

          if (canRxFrame.DLC == 4 &&

              canRxFrame.RTR == CAN_RTR_DATA &&

              canRxFrame.IDE == CAN_IDE_STD &&

              canRxFrame.SID == SSSP_STACKINIT_CANMSGID_MODULEID) {

            aosDbgPrintf("ID (%u)\n", _canDeserialize32(canRxFrame.data8));

            // validate received ID

            if (lastid < _canDeserialize32(canRxFrame.data8)) {

              // store received ID

              lastid = _canDeserialize32(canRxFrame.data8);

              // restart timeout timer

              chVTSet(&timerTimeout, LL_US2ST(AOS_SYSTEM_SSSP_TIMEOUT), _ssspTimerCallback, &eventSourceTimeout);

            } else {

              aosDbgPrintf("ERR: invalid ID\n");

              // abort

              stage = STAGE_3_4_ABORT_ACTIVE;

              flags.wfe_next = false;

            }

            // explicitely clear timeout event flag

            chEvtWaitAnyTimeout(TIMEOUTEVENT_MASK, TIME_IMMEDIATE);

            eventmask &= ~TIMEOUTEVENT_MASK;

          }

        }

        // if an IO event was received (DN signal)

        if ((eventmask & IOEVENT_MASK) && (ioflags & MODULE_SSSP_EVENTFLAGS_DN)) {

          aosDbgPrintf("DN <-\n");

          // reset timeout timer

          chVTReset(&timerTimeout);

          chEvtWaitAnyTimeout(TIMEOUTEVENT_MASK, TIME_IMMEDIATE);

          eventmask &= ~TIMEOUTEVENT_MASK;

          // increment and broadcast ID

          aos.sssp.moduleId = lastid + 1;

          aosDbgPrintf("CAN -> ID (%u)\n", aos.sssp.moduleId);

          canTxFrame.DLC = 4;

          canTxFrame.SID = SSSP_STACKINIT_CANMSGID_MODULEID;

          _canSerialize32(canTxFrame.data8, aos.sssp.moduleId);

          if (canTransmitTimeout(&MODULE_HAL_CAN, CAN_ANY_MAILBOX, &canTxFrame, TIME_IMMEDIATE) != MSG_OK) {

            chEvtBroadcast(&eventSourceTimeout);

            break;

          }

          // set delay timer

          chVTSet(&timerDelay, LL_US2ST(AMIROOS_CFG_SSSP_SIGNALDELAY), _ssspTimerCallback, &eventSourceDelay);

        }

        // if a delay event occurred

        if (eventmask & DELAYEVENT_MASK) {

#if (AMIROOS_CFG_SSSP_STACK_END != true)

          // activate UP

          aosDbgPrintf("UP+\n");

          apalControlGpioSet(&moduleSsspGpioUp, APAL_GPIO_ON);

#endif

          // deactivate S

          aosDbgPrintf("S-\n");

          apalControlGpioSet(&moduleSsspGpioSync, APAL_GPIO_OFF);

          // reset the timeout timer

          chVTSet(&timerTimeout, LL_US2ST(AOS_SYSTEM_SSSP_TIMEOUT), _ssspTimerCallback, &eventSourceTimeout);

          chEvtWaitAnyTimeout(TIMEOUTEVENT_MASK, TIME_IMMEDIATE);

          eventmask &= ~TIMEOUTEVENT_MASK;

          // proceed

          stage = STAGE_3_3_WAITFORID;

        }

#endif

        break;

      } /* end of STAGE_3_3_WAITFORIDORSIG */

      case STAGE_3_3_WAITFORID:

      {

        aos.sssp.stage = AOS_SSSP_STARTUP_3_3;

#if (AMIROOS_CFG_SSSP_STACK_END != true)

        // a CAN message was received

        if (eventmask & CANEVENT_MASK) {

          // if an ID message was received

          if (canRxFrame.DLC == 4 &&

              canRxFrame.RTR == CAN_RTR_DATA &&

              canRxFrame.IDE == CAN_IDE_STD &&

              canRxFrame.SID == SSSP_STACKINIT_CANMSGID_MODULEID) {

#if (AMIROOS_CFG_SSSP_STACK_START != true) || (AMIROOS_CFG_DBG == true)

            // Plausibility of the received ID is not checked at this point but is done by other modules still in a previous stage.

            lastid = _canDeserialize32(canRxFrame.data8);

            aosDbgPrintf("ID (%u)\n", lastid);

#endif

            // restart timeout timer

            chVTSet(&timerTimeout, LL_US2ST(AOS_SYSTEM_SSSP_TIMEOUT), _ssspTimerCallback, &eventSourceTimeout);

            chEvtWaitAnyTimeout(TIMEOUTEVENT_MASK, TIME_IMMEDIATE);

            eventmask &= ~TIMEOUTEVENT_MASK;

          }

        }

#endif

        break;

      } /* end of STAGE_3_3_WAITFORID */

      case STAGE_3_4_FINISH:

      {