Slotted CSMA Module

Transmits data using Slotted CSMA/CA mechanism.

Macros
#define	ACK_FRAME   (0x02)
#define	ACK_FRAME_LEN   (0x05)
#define	CCA_GUARD_DURATION_US
#define	CONVERT_OCTETS_TO_SYM(octets)   (2 * octets)
#define	CSMA_BEACON_LOSS_GUARD_TIME_US   (2000)
#define	PRE_BEACON_GUARD_TIME_US   (1000)

Typedefs
typedef enum csma_state_tag	csma_state_t

Enumerations
enum	csma_state_tag {   CSMA_IDLE = 0,   BACKOFF_WAITING_FOR_CCA_TIMER,   BACKOFF_WAITING_FOR_BEACON,   CSMA_ACCESS_FAILURE,   FRAME_SENDING,   TX_DONE_SUCCESS,   TX_DONE_FRAME_PENDING,   TX_DONE_NO_ACK,   NO_BEACON_TRACKING,   CSMA_HANDLE_BEACON,   CSMA_IDLE = 0,   BACKOFF_WAITING_FOR_CCA_TIMER,   BACKOFF_WAITING_FOR_BEACON,   CSMA_ACCESS_FAILURE,   FRAME_SENDING,   TX_DONE_SUCCESS,   TX_DONE_FRAME_PENDING,   TX_DONE_NO_ACK,   NO_BEACON_TRACKING,   CSMA_HANDLE_BEACON }

Functions
static void	beacon_loss_timer_cb (void *parameter)
	Handler for beacon loss timer. More...
static void	calculate_transaction_duration (void)
	Calculates the entire transaction duration. More...
static void	cca_timer_handler_cb (void *parameter)
	CCA timer callback. More...
static bool	check_beacon_reception (void)
	Checks if node is receiving beacons. More...
static void	csma_backoff_calculation (void)
	Calculates backoff duration and handles the start of the CCA. More...
static void	csma_param_init (void)
	Initializes CSMA variables. More...
static uint8_t	perform_cca_twice (void)
	Performs CCA twice. More...
static void	send_frame_at_next_backoff_boundary (void)
	Sends the frame at the next backoff boundary. More...
static void	start_beacon_loss_timer (void)
	Starts the beacon loss timer. More...
static void	tx_done (retval_t status)
	Finalizes the CSMA procedure. More...

Variables
static uint8_t	BE
static uint32_t	cca_starttime_us
static uint8_t	NB
static uint8_t	number_of_tx_retries
static uint8_t	remaining_backoff_periods
static uint8_t	transaction_duration_periods

#define ACK_FRAME   (0x02)

#define ACK_FRAME_LEN   (0x05)

Referenced by calc_frame_transmit_duration(), and calculate_transaction_duration().

#define CCA_GUARD_DURATION_US

Value:

(1000)  /* used for calculation overhead
                                            **/

Referenced by csma_backoff_calculation().

#define CONVERT_OCTETS_TO_SYM

(

octets

)

(2 * octets)

Referenced by calc_frame_transmit_duration(), and calculate_transaction_duration().

#define CSMA_BEACON_LOSS_GUARD_TIME_US   (2000)

Referenced by start_beacon_loss_timer().

#define PRE_BEACON_GUARD_TIME_US   (1000)

Referenced by csma_backoff_calculation().

typedef enum csma_state_tag csma_state_t

enum csma_state_tag

Enumerator
CSMA_IDLE
BACKOFF_WAITING_FOR_CCA_TIMER
BACKOFF_WAITING_FOR_BEACON
CSMA_ACCESS_FAILURE
FRAME_SENDING
TX_DONE_SUCCESS
TX_DONE_FRAME_PENDING
TX_DONE_NO_ACK
NO_BEACON_TRACKING
CSMA_HANDLE_BEACON
CSMA_IDLE
BACKOFF_WAITING_FOR_CCA_TIMER
BACKOFF_WAITING_FOR_BEACON
CSMA_ACCESS_FAILURE
FRAME_SENDING
TX_DONE_SUCCESS
TX_DONE_FRAME_PENDING
TX_DONE_NO_ACK
NO_BEACON_TRACKING
CSMA_HANDLE_BEACON

static void beacon_loss_timer_cb ( void *  parameter )

static

Handler for beacon loss timer.

Parameters

parameter

Unused callback parameter

References Assert, BACKOFF_WAITING_FOR_BEACON, NO_BEACON_TRACKING, PIN_BEACON_LOSS_TIMER_END, and tal_csma_state.

Referenced by start_beacon_loss_timer().

static void calculate_transaction_duration ( void  )

static

Calculates the entire transaction duration.

References ACK_FRAME_LEN, aMaxSIFSFrameSize, aTurnaroundTime, aUnitBackoffPeriod, CONVERT_OCTETS_TO_SYM, FCF_ACK_REQUEST, mac_frame_ptr, macMinLIFSPeriod_def, macMinSIFSPeriod_def, frame_info_tag::mpdu, PHY_OVERHEAD, PL_POS_FCF_1, tal_frame_to_tx, and transaction_duration_periods.

Referenced by slotted_csma_start(), and tal_tx_frame().

static void cca_timer_handler_cb ( void *  parameter )

static

CCA timer callback.

Parameters

parameter

Unused callback parameter

References CSMA_ACCESS_FAILURE, perform_cca_twice(), PHY_IDLE, PIN_BACKOFF_END, send_frame_at_next_backoff_boundary(), and tal_csma_state.

Referenced by csma_backoff_calculation().

static bool check_beacon_reception ( void  )

static

Checks if node is receiving beacons.

Returns

true: beacons are received otherwise false

References aMaxLostBeacons, pal_get_current_time(), tal_add_time_symbols(), TAL_CONVERT_US_TO_SYMBOLS, TAL_GET_BEACON_INTERVAL_TIME, and tal_pib.

Referenced by slotted_csma_start().

static void csma_backoff_calculation ( void  )

static

Calculates backoff duration and handles the start of the CCA.

References Assert, aUnitBackoffPeriod, BACKOFF_WAITING_FOR_BEACON, BACKOFF_WAITING_FOR_CCA_TIMER, BE, CCA_GUARD_DURATION_US, CCA_PREPARATION_DURATION_US, cca_starttime_us, cca_timer_handler_cb(), CSMA_ACCESS_FAILURE, FUNC_PTR, MAC_SUCCESS, NB, NULL, pal_add_time_us(), pal_get_current_time(), pal_sub_time_us(), pal_timer_start(), PAL_TMR_INVALID_TIMEOUT, PIN_BACKOFF_START, PRE_BEACON_GUARD_TIME_US, remaining_backoff_periods, SLEEP_TO_TRX_OFF_TYP_US, start_beacon_loss_timer(), tal_add_time_symbols(), TAL_CONVERT_SYMBOLS_TO_US, TAL_CONVERT_US_TO_SYMBOLS, TAL_CSMA_CCA, tal_csma_state, TAL_GET_SUPERFRAME_DURATION_TIME, tal_pib, TAL_RADIO_WAKEUP_TIME_SYM, tal_sub_time_symbols(), TIMEOUT_ABSOLUTE, and transaction_duration_periods.

Referenced by slotted_csma_start(), and slotted_csma_state_handling().

static void csma_param_init ( void  )

inlinestatic

Initializes CSMA variables.

References BE, NB, and tal_pib.

Referenced by slotted_csma_start().

static uint8_t perform_cca_twice ( void  )

static

Performs CCA twice.

References Assert, aUnitBackoffPeriod, CCA_CH_IDLE, CCA_COMPLETED, CCA_DURATION_SYM, CCA_PRE_START_DURATION_US, CCA_PREPARATION_DURATION_US, CCA_START, cca_starttime_us, CMD_PLL_ON, CMD_RX_AACK_ON, CMD_RX_ON, CMD_TRX_OFF, pal_add_time_us(), pal_get_current_time(), pal_timer_delay(), PHY_BUSY, PHY_IDLE, PIN_CCA_END, PIN_CCA_START, PLL_ON, RG_IRQ_STATUS, RX_DISABLE, RX_ENABLE, set_trx_state(), SLEEP_TO_TRX_OFF_TYP_US, SR_CCA_DONE, SR_CCA_REQUEST, SR_CCA_STATUS, SR_RX_PDT_DIS, TAL_CONVERT_SYMBOLS_TO_US, tal_trx_status, trx_bit_read, trx_bit_write, TRX_OFF_TO_PLL_ON_TIME_US, trx_reg_write, and TRX_SLEEP.

Referenced by cca_timer_handler_cb().

static void send_frame_at_next_backoff_boundary ( void  )

static

Sends the frame at the next backoff boundary.

References cca_starttime_us, FRAME_SENDING, NO_CSMA_NO_IFS, pal_add_time_us(), pal_get_current_time(), PIN_TX_START, PRE_TX_DURATION_US, send_frame(), and tal_csma_state.

Referenced by cca_timer_handler_cb().

static void start_beacon_loss_timer ( void  )

static

Starts the beacon loss timer.

References aMaxLostBeacons, Assert, beacon_loss_timer_cb(), CSMA_BEACON_LOSS_GUARD_TIME_US, FUNC_PTR, MAC_SUCCESS, NULL, pal_timer_start(), PAL_TMR_ALREADY_RUNNING, PAL_TMR_INVALID_TIMEOUT, PIN_BEACON_LOSS_TIMER_START, TAL_CONVERT_SYMBOLS_TO_US, TAL_CSMA_BEACON_LOSS_TIMER, TAL_GET_BEACON_INTERVAL_TIME, tal_pib, and TIMEOUT_RELATIVE.

Referenced by csma_backoff_calculation().

static void tx_done ( retval_t  status )

static

Finalizes the CSMA procedure.

Parameters

status

Result of the slotted transmission

References Assert, CSMA_IDLE, mac_frame_ptr, pal_is_timer_running(), PIN_CSMA_END, TAL_CSMA_BEACON_LOSS_TIMER, tal_csma_state, TAL_IDLE, TAL_SLOTTED_CSMA, tal_state, and tal_tx_frame_done_cb().

Referenced by slotted_csma_state_handling().

uint8_t BE

static

Referenced by csma_backoff_calculation(), csma_param_init(), slotted_csma_start(), and slotted_csma_state_handling().

uint32_t cca_starttime_us

static

Referenced by csma_backoff_calculation(), perform_cca_twice(), and send_frame_at_next_backoff_boundary().

uint8_t NB

static

Referenced by csma_backoff_calculation(), csma_param_init(), and slotted_csma_state_handling().

uint8_t number_of_tx_retries

static

Referenced by slotted_csma_start(), and slotted_csma_state_handling().

uint8_t remaining_backoff_periods

static

Referenced by csma_backoff_calculation(), slotted_csma_start(), and slotted_csma_state_handling().

uint8_t transaction_duration_periods

static

Referenced by calculate_transaction_duration(), csma_backoff_calculation(), and tal_tx_frame().