Angle of Arrival/Departure
RAIL API > Protocol-specific > BLE

These APIs are to a stack implementing BLE's angle of arrival and angle of departure functionality.

Data Structures

struct RAIL_BLE_AoxConfig_t
Contains arguments for RAIL_BLE_ConfigAox function.
struct RAIL_BLE_AoxAntennaPortPins_t
Contains elements of RAIL_BLE_AoxAntennaConfig_t struct.
struct RAIL_BLE_AoxAntennaConfig_t
Contains arguments for RAIL_BLE_ConfigAoxAntenna function for EFR32XG22.

Macros

#define RAIL_BLE_AOX_ANTENNA_PIN_COUNT (6U)
The maximum number of GPIO pins used for AoX Antenna switching.
#define RAIL_BLE_AOX_OPTIONS_DO_SWITCH (0U)
Deprecated AOX options.
#define RAIL_BLE_AOX_OPTIONS_TX_ENABLED (0U)
Deprecated AOX options.
#define RAIL_BLE_AOX_OPTIONS_RX_ENABLED (0U)
Deprecated AOX options.
#define RAIL_BLE_AOX_OPTIONS_DISABLED (0U)
Disable the AoX feature.
#define RAIL_BLE_AOX_OPTIONS_SAMPLE_MODE (1U << RAIL_BLE_AOX_OPTIONS_SAMPLE_MODE_SHIFT)
Sets one of the two AoX sampling/switching modes: 1 us or 2 us window.
#define RAIL_BLE_AOX_OPTIONS_CONNLESS (1U << RAIL_BLE_AOX_OPTIONS_CONNLESS_SHIFT)
Enables connectionless AoX Rx packets.
#define RAIL_BLE_AOX_OPTIONS_CONN (1U << RAIL_BLE_AOX_OPTIONS_CONN_SHIFT)
Enables connection based AoX Rx packets.
#define RAIL_BLE_AOX_OPTIONS_DISABLE_BUFFER_LOCK (1U << RAIL_BLE_AOX_OPTIONS_BUFFER_LOCK_SHIFT)
Disables CTE buffer lock.
#define RAIL_BLE_AOX_OPTIONS_ENABLED ( RAIL_BLE_AOX_OPTIONS_CONN | RAIL_BLE_AOX_OPTIONS_CONNLESS )
Enables connection based or connectionless AoX Rx packets.

Enumerations

enum RAIL_BLE_AoxOptions_t {
RAIL_BLE_AOX_OPTIONS_SAMPLE_MODE_SHIFT = 0,
RAIL_BLE_AOX_OPTIONS_CONNLESS_SHIFT = 1,
RAIL_BLE_AOX_OPTIONS_CONN_SHIFT = 2,
RAIL_BLE_AOX_OPTIONS_LOCK_CTE_BUFFER_SHIFT = 3
}
Angle of Arrival/Departure options bit fields.

Functions

bool RAIL_BLE_LockCteBuffer ( RAIL_Handle_t railHandle, bool lock)
Lock/unlock the CTE buffer from the application's perspective.
bool RAIL_BLE_CteBufferIsLocked ( RAIL_Handle_t railHandle)
Determine whether the CTE buffer is currently locked or not.
uint8_t RAIL_BLE_GetCteSampleOffset ( RAIL_Handle_t railHandle)
Get the offset into CTE sample of CTE data.
uint32_t RAIL_BLE_GetCteSampleRate ( RAIL_Handle_t railHandle)
Get the effective sample rate used by the ADC to capture the CTE samples.
RAIL_Status_t RAIL_BLE_ConfigAox ( RAIL_Handle_t railHandle, const RAIL_BLE_AoxConfig_t *aoxConfig)
Configure Angle of Arrival/Departure (AoX) functionality.
RAIL_Status_t RAIL_BLE_InitCte ( RAIL_Handle_t railHandle)
Perform one time initialization of AoX registers.
RAIL_Status_t RAIL_BLE_ConfigAoxAntenna ( RAIL_Handle_t railHandle, RAIL_BLE_AoxAntennaConfig_t *antennaConfig)
Perform initialization of AoX antenna GPIO pins.

Detailed Description

These APIs are to a stack implementing BLE's angle of arrival and angle of departure functionality.

They are designed for use by the Silicon Labs BLE stack only at this time and may cause problems if accessed directly.

Macro Definition Documentation

◆ RAIL_BLE_AOX_ANTENNA_PIN_COUNT

#define RAIL_BLE_AOX_ANTENNA_PIN_COUNT   (6U)

The maximum number of GPIO pins used for AoX Antenna switching.

If the user configures more pins using RAIL_BLE_ConfigAoxAntenna than allowed RAIL_BLE_AOX_ANTENNA_PIN_COUNT , then RAIL_STATUS_INVALID_PARAMETER status will be returned.

RAIL_STATUS_INVALID_CALL is returned if : RAIL_BLE_AOX_ANTENNA_PIN_COUNT is set to 0 or The user configures no pins.

The maximum value RAIL_BLE_AOX_ANTENNA_PIN_COUNT can take depends on number of Antenna route pins , a chip provides. For EFR32XG22, the maximum value of RAIL_BLE_AOX_ANTENNA_PIN_COUNT is 6. If the user configures fewer pins than RAIL_BLE_AOX_ANTENNA_PIN_COUNT , then only number of pins asked by user will be configured with RAIL_STATUS_NO_ERROR .

Definition at line 495 of file rail_ble.h .

Enumeration Type Documentation

◆ RAIL_BLE_AoxOptions_t

enum RAIL_BLE_AoxOptions_t

Angle of Arrival/Departure options bit fields.

Enumerator
RAIL_BLE_AOX_OPTIONS_SAMPLE_MODE_SHIFT

Shift position of RAIL_BLE_AOX_OPTIONS_SAMPLE_MODE bit.

RAIL_BLE_AOX_OPTIONS_CONNLESS_SHIFT

Shift position of RAIL_BLE_AOX_OPTIONS_CONNLESS_SHIFT bit.

RAIL_BLE_AOX_OPTIONS_CONN_SHIFT

Shift position of RAIL_BLE_AOX_OPTIONS_CONN_SHIFT bit.

RAIL_BLE_AOX_OPTIONS_LOCK_CTE_BUFFER_SHIFT

Shift position of RAIL_BLE_AOX_OPTIONS_LOCK_CTE_BUFFER_SHIFT bit.

Definition at line 501 of file rail_ble.h .

Function Documentation

◆ RAIL_BLE_ConfigAox()

RAIL_Status_t RAIL_BLE_ConfigAox ( RAIL_Handle_t railHandle,
const RAIL_BLE_AoxConfig_t * aoxConfig
)

Configure Angle of Arrival/Departure (AoX) functionality.

AoX is a method of radio localization which infers angle of arrival/departure of the signal based on different phases of the raw I/Q signal from different antennas by controlling external RF switch during the continuous tone extension (CTE). Connection based AoX packets are different than normal BLE packets in that they have 3 header bytes instead of 2 and they have CTE appended after the payload's CRC. 3rd byte or CTE info contains CTE length. Connectionless AoX packets have 2 header bytes and CTE info is part of the payload. AoX is supported on EFR32XG12/13/14 only on legacy 1Mbps BLE PHY. Note that calling RAIL_GetRadioEntropy during AoX reception may break receiving packets.

Parameters
[in] railHandle A RAIL instance handle.
[in] aoxConfig Configuration options for AoX
Returns
RAIL_Status_t indicating success or failure of the call.

◆ RAIL_BLE_ConfigAoxAntenna()

RAIL_Status_t RAIL_BLE_ConfigAoxAntenna ( RAIL_Handle_t railHandle,
RAIL_BLE_AoxAntennaConfig_t * antennaConfig
)

Perform initialization of AoX antenna GPIO pins.

This function must be called before calls to RAIL_BLE_InitCte and RAIL_BLE_ConfigAox , and before configuring the BLE PHY, else a RAIL_STATUS_INVALID_CALL is returned.

If user configures more pins, i.e., antCount in RAIL_BLE_AoxAntennaConfig_t , than allowed RAIL_BLE_AOX_ANTENNA_PIN_COUNT , then the API returns RAIL_STATUS_INVALID_PARAMETER .

If user configures lesser than or equal to number of pins allowed by RAIL_BLE_AOX_ANTENNA_PIN_COUNT , then the requested number of pins are configured and RAIL_STATUS_NO_ERROR is returned.

Parameters
[in] railHandle A RAIL instance handle.
[in] antennaConfig structure to hold the set of ports and pins to configure Antenna pins for AoX Antenna switching.
Returns
RAIL_Status_t indicating success or failure of the call.

◆ RAIL_BLE_CteBufferIsLocked()

bool RAIL_BLE_CteBufferIsLocked ( RAIL_Handle_t railHandle )

Determine whether the CTE buffer is currently locked or not.

Parameters
[in] railHandle A handle for RAIL instance.
Returns
True if CTE buffer is locked and false otherwise.

◆ RAIL_BLE_GetCteSampleOffset()

uint8_t RAIL_BLE_GetCteSampleOffset ( RAIL_Handle_t railHandle )

Get the offset into CTE sample of CTE data.

Parameters
[in] railHandle A handle for RAIL instance.
Returns
The offset of CTE data in a CTE sample in bytes. On unsupported platforms this returns 0.

◆ RAIL_BLE_GetCteSampleRate()

uint32_t RAIL_BLE_GetCteSampleRate ( RAIL_Handle_t railHandle )

Get the effective sample rate used by the ADC to capture the CTE samples.

Parameters
[in] railHandle A handle for RAIL instance.
Returns
The actual sample rate used to capture the CTE in samples per second. On unsupported platforms this returns 0.

◆ RAIL_BLE_InitCte()

RAIL_Status_t RAIL_BLE_InitCte ( RAIL_Handle_t railHandle )

Perform one time initialization of AoX registers.

This function must be called before RAIL_BLE_ConfigAox and before configuring the BLE PHY.

Parameters
[in] railHandle A RAIL instance handle.
Returns
RAIL_Status_t indicating success or failure of the call.

◆ RAIL_BLE_LockCteBuffer()

bool RAIL_BLE_LockCteBuffer ( RAIL_Handle_t railHandle,
bool lock
)

Lock/unlock the CTE buffer from the application's perspective.

The radio will write to the buffer only if the bit is NOT set at the beginning of the sampling period. The radio will set the bit once the sampling period starts to indicate that some CTE data has been collected, which will not be overwritten during the next sampling period, unless the buffer is unlocked by the application.

Parameters
[in] railHandle A RAIL instance handle.
[in] lock Lock the CTE buffer if true and unlock it if false.
Returns
True if the CTE buffer is locked after the call, otherwise false.