/**
* \brief State machine handling slotted CSMA
*/
void slotted_csma_state_handling(void)
{
switch (tal_csma_state) {
case BACKOFF_WAITING_FOR_CCA_TIMER:
break;
case BACKOFF_WAITING_FOR_BEACON:
/*
* Do not perform any operation and wait until the next beacon
* reception. If several beacons are not received, the beacon
* loss
* timer expires and stops the entire transaction.
*/
break;
case CSMA_HANDLE_BEACON:
/* debug pin to switch on: define ENABLE_DEBUG_PINS,
* pal_config.h */
PIN_WAITING_FOR_BEACON_END();
PIN_BEACON_LOSS_TIMER_END();
pal_timer_stop(TAL_CSMA_BEACON_LOSS_TIMER);
csma_backoff_calculation();
break;
case CSMA_ACCESS_FAILURE:
NB++;
BE++;
/* ensure that BE is no more than macMaxBE */
if (BE > tal_pib.MaxBE) { /* macMaxBE */
BE = tal_pib.MaxBE; /* macMaxBE */
}
if (NB > macMaxCSMABackoffs) {
/* terminate with channel access failure */
tx_done(MAC_CHANNEL_ACCESS_FAILURE);
} else {
/* restart backoff */
csma_backoff_calculation();
}
break;
case NO_BEACON_TRACKING:
/* terminate with channel access failure */
tx_done(MAC_CHANNEL_ACCESS_FAILURE);
break;
case FRAME_SENDING:
/* waiting for end of frame transmission */
break;
case TX_DONE_SUCCESS:
tx_done(MAC_SUCCESS);
break;
case TX_DONE_FRAME_PENDING:
tx_done(TAL_FRAME_PENDING);
break;
case TX_DONE_NO_ACK:
if (number_of_tx_retries < tal_pib.MaxFrameRetries) {
number_of_tx_retries++;
set_trx_state(CMD_RX_AACK_ON);
/*
* Start the entire CSMA procedure again,
* but do not reset the number of transmission attempts.
*/
BE++;
/* ensure that BE is no more than macMaxBE */
if (BE > tal_pib.MaxBE) { /* macMaxBE */
BE = tal_pib.MaxBE; /* macMaxBE */
}
NB = 0;
remaining_backoff_periods
= (uint8_t)(rand() & ((1 << BE) - 1));
csma_backoff_calculation();
} else {
tx_done(MAC_NO_ACK);
}
PIN_NO_ACK_END();
break;
default:
Assert("INVALID CSMA status" == 0);
break;
}
} /* csma_ca_state_handling() */
/*
* \brief Parses received frame and create the frame_info_t structure
*
* This function parses the received frame and creates the frame_info_t
* structure to be sent to the MAC as a parameter of tal_rx_frame_cb().
*
* \param buf Pointer to the buffer containing the received frame
*/
void process_incoming_frame(buffer_t *buf_ptr)
{
#ifndef TRX_REG_RAW_VALUE
uint8_t frame_len;
uint8_t *frame_ptr;
uint8_t ed_level;
uint8_t lqi;
#endif
frame_info_t *receive_frame = (frame_info_t *)BMM_BUFFER_POINTER(buf_ptr);
/* The frame is present towards the end of the buffer. */
#ifndef TRX_REG_RAW_VALUE
/*
* Store the last frame length for IFS handling.
* Substract LQI and length fields.
*/
frame_len = last_frame_length = receive_frame->mpdu[0];
#else
last_frame_length = receive_frame->mpdu[0];
#endif
#ifdef PROMISCUOUS_MODE
if (tal_pib.PromiscuousMode)
{
#ifndef TRX_REG_RAW_VALUE
frame_ptr = &(receive_frame->mpdu[frame_len + LQI_LEN]);
/*
* The LQI is stored after the FCS.
* The ED value is stored after the LQI.
*/
lqi = *frame_ptr++;
ed_level = *frame_ptr;
/*
* The LQI normalization is done using the ED level measured during
* the frame reception.
*/
#ifdef RSSI_TO_LQI_MAPPING
lqi = normalize_lqi(ed_level);
#else
lqi = normalize_lqi(lqi, ed_level);
#endif
/* Store normalized LQI value again. */
frame_ptr--;
*frame_ptr = lqi;
#endif /* #ifndef TRX_REG_RAW_VALUE */
receive_frame->buffer_header = buf_ptr;
/* The callback function implemented by MAC is invoked. */
tal_rx_frame_cb(receive_frame);
return;
}
#endif /* #ifdef PROMISCUOUS_MODE */
#ifdef BEACON_SUPPORT
/*
* Are we waiting for a beacon for slotted CSMA?
* Check if received frame is a beacon.
*/
if ((receive_frame->mpdu[PL_POS_FCF_1] & FCF_FRAMETYPE_MASK) == FCF_FRAMETYPE_BEACON)
{
/* Debug pin to switch on: define ENABLE_DEBUG_PINS, pal_config.h */
PIN_BEACON_START();
if (tal_csma_state == BACKOFF_WAITING_FOR_BEACON)
{
/* Debug pin to switch on: define ENABLE_DEBUG_PINS, pal_config.h */
PIN_WAITING_FOR_BEACON_END();
tal_pib.BeaconTxTime = TAL_CONVERT_US_TO_SYMBOLS(receive_frame->time_stamp);
tal_csma_state = CSMA_HANDLE_BEACON;
}
/* Debug pin to switch on: define ENABLE_DEBUG_PINS, pal_config.h */
PIN_BEACON_END();
}
#endif /* BEACON_SUPPORT */
#ifndef TRX_REG_RAW_VALUE
/*
* The LQI is stored after the FCS.
* The ED value is stored after the LQI.
*/
frame_ptr = &(receive_frame->mpdu[frame_len + LQI_LEN]);
lqi = *frame_ptr++;
ed_level = *frame_ptr;
/*
* The LQI normalization is done using the ED level measured during
* the frame reception.
*/
#ifdef RSSI_TO_LQI_MAPPING
lqi = normalize_lqi(ed_level);
#else
lqi = normalize_lqi(lqi, ed_level);
#endif
/* Store normalized LQI value again. */
frame_ptr--;
*frame_ptr = lqi;
#endif /* #ifndef TRX_REG_RAW_VALUE */
receive_frame->buffer_header = buf_ptr;
#ifdef ENABLE_RTB
/* The callback function implemented by RTB is invoked. */
rtb_rx_frame_cb(receive_frame);
#else
/* The callback function implemented by MAC is invoked. */
tal_rx_frame_cb(receive_frame);
#endif
} /* process_incoming_frame() */
