Connection#

Modules#

sl_bt_evt_connection_opened
Indicates that a new connection was opened.

sl_bt_evt_connection_parameters
Triggered whenever the connection parameters are changed and at any time a connection is established.

sl_bt_evt_connection_phy_status
Indicates that PHY update procedure is completed.

sl_bt_evt_connection_rssi
Triggered when an connection_get_rssi command has completed.

sl_bt_evt_connection_closed
Indicates that a connection was closed.

Enumerations#

enum   connection_security_t {
    connection_mode1_level1 = 0x0,
    connection_mode1_level2 = 0x1,
    connection_mode1_level3 = 0x2,
    connection_mode1_level4 = 0x3
}
Security Modes.

Functions#

sl_status_t  sl_bt_connection_set_default_parameters
    (uint16_t min_interval, uint16_t max_interval, uint16_t latency, uint16_t timeout, uint16_t min_ce_length, uint16_t max_ce_length)

sl_status_t  sl_bt_connection_set_default_preferred_phy    

(uint8_t preferred_phy, uint8_t accepted_phy)

sl_status_t  sl_bt_connection_open\     (bd_addr address, uint8_t address_type, uint8_t initiating_phy, uint8_t *connection)

sl_status_t  sl_bt_connection_set_parameters\     (uint8_t connection, uint16_t min_interval, uint16_t max_interval, uint16_t latency, uint16_t timeout, uint16_t min_ce_length, uint16_t max_ce_length)

sl_status_t  sl_bt_connection_set_preferred_phy
(uint8_t connection, uint8_t preferred_phy, uint8_t accepted_phy)

sl_status_t  sl_bt_connection_disable_slave_latency\     (uint8_t connection, uint8_t disable)

sl_status_t  sl_bt_connection_get_rssi\     (uint8_t connection)

sl_status_t  sl_bt_connection_read_channel_map\     (uint8_t connection, size_t max_channel_map_size, size_t *channel_map_len, uint8_t *channel_map)

sl_status_t  sl_bt_connection_close\     (uint8_t connection)

Detailed Description#

Connection.

The commands and events in this class are related to managing connection establishment, parameter setting, and disconnection procedures.

Enumeration Type Documentation#

connection_security_t#

enum connection_security_t

Security Modes.

Enumerator

connection_mode1_level1 

(0x0) No security

connection_mode1_level2 

(0x1) Unauthenticated pairing with encryption

connection_mode1_level3 

(0x2) Authenticated pairing with encryption

connection_mode1_level4 

(0x3) Authenticated Secure Connections pairing with encryption using a 128-bit strength encryption key

Function Documentation#

sl_bt_connection_set_default_parameters()#

sl_status_t sl_bt_connection_set_default_parameters

( uint16_t 

min_interval,

uint16_t 

max_interval,

uint16_t 

latency,

uint16_t 

timeout,

uint16_t 

min_ce_length,

uint16_t 

max_ce_length

)

Set the default Bluetooth connection parameters. The values are valid for all subsequent connections initiated by this device. To change parameters of an already established connection, use the command sl_bt_connection_set_parameters.

Parameters#

[in]

min_interval

Minimum value for the connection event interval. This must be set less than or equal to max_interval.

Default value: 20 ms

  • Time = Value x 1.25 ms

  • Range: 0x0006 to 0x0c80

  • Time Range: 7.5 ms to 4 s

[in]

max_interval

Maximum value for the connection event interval. This must be set greater than or equal to min_interval.

Default value: 50 ms

  • Time = Value x 1.25 ms

  • Range: 0x0006 to 0x0c80

  • Time Range: 7.5 ms to 4 s

[in]

latency

Slave latency, which defines how many connection intervals the slave can skip if it has no data to send

Default value: 0

  • Range: 0x0000 to 0x01f4

[in]

timeout

Supervision timeout, which defines the time that the connection is maintained although the devices can't communicate at the currently configured connection intervals.

The value in milliseconds must be larger than (1 + latency) * max_interval * 2, where max_interval is given in milliseconds. Set the supervision timeout at a value which allows communication attempts over at least a few connection intervals.

Default value: 1000 ms

  • Range: 0x000a to 0x0c80

  • Time = Value x 10 ms

  • Time Range: 100 ms to 32 s

[in]

min_ce_length

Minimum value for the connection event length. This must be set be less than or equal to max_ce_length.

Value is not currently used and is reserved for future. Set to 0.

Default value: 0x0000

  • Time = Value x 0.625 ms

  • Range: 0x0000 to 0xffff

[in]

max_ce_length

  • Time = Value x 0.625 ms

  • Range: 0x0000 to 0xffff

Returns SL_STATUS_OK if successful. Error code otherwise.

sl_bt_connection_set_default_preferred_phy()#

sl_status_t sl_bt_connection_set_default_preferred_phy

( uint8_t 

preferred_phy,

uint8_t 

accepted_phy)

Set default preferred and accepted PHYs. PHY settings will be used for all subsequent connections. Non-preferred PHY can also be set if the remote device does not accept any of the preferred PHYs.

The parameter accepted_phy is used to specify PHYs that the stack can accept in a remotely-initiated PHY update request. A PHY update will not happen if none of the accepted PHYs are present in the request.

NOTE: 2M and Coded PHYs are not supported by all devices.

Parameters

[in]

preferred_phy

Preferred PHYs. This parameter is a bitfield and multiple PHYs can be set. Default: 0xff (no preference)

  • 0x01: 1M PHY

  • 0x02: 2M PHY

  • 0x04: Coded PHY

  • 0xff: Any PHYs

[in]

accepted_phy

Accepted PHYs in remotely-initiated PHY update request. This parameter is a bitfield and multiple PHYs can be set. Default: 0xff (all PHYs accepted)

  • 0x01: 1M PHY

  • 0x02: 2M PHY

  • 0x04: Coded PHY

  • 0xff: Any PHYs

Returns SL_STATUS_OK if successful. Error code otherwise.

sl_bt_connection_open()#

sl_status_t sl_bt_connection_open

( bd_addr

address,

uint8_t 

address_type,

uint8_t 

initiating_phy,

uint8_t * 

connection )

Connect to an advertising device with the specified initiating PHY on which connectable advertisements on primary advertising channels are received. The Bluetooth stack will enter a state where it continuously scans for the connectable advertising packets from the remote device, which matches the Bluetooth address given as a parameter. Scan parameters set in sl_bt_scanner_set_timing are used in this operation. Upon receiving the advertising packet, the module will send a connection request packet to the target device to initiate a Bluetooth connection. To cancel an ongoing connection process, use sl_bt_connection_close command with the handle received in response from this command.

A connection is opened in no-security mode. If the GATT client needs to read or write the attributes on GATT server requiring encryption or authentication, it must first encrypt the connection using an appropriate authentication method.

If a connection can't be established (for example, the remote device has gone out of range, has entered into deep sleep, or is not advertising), the stack will try to connect forever. In this case, the application will not get an event related to the connection request. To recover from this situation, the application can implement a timeout and call sl_bt_connection_close to cancel the connection request.

This command fails with the connection limit exceeded error if the number of connections attempted exceeds the configured MAX_CONNECTIONS value.

This command fails with the invalid parameter error if the initiating PHY value is invalid or the device does not support PHY.

Later calls of this command have to wait for the ongoing command to complete. A received event sl_bt_evt_connection_opened indicates that the connection opened successfully and a received event sl_bt_evt_connection_closed indicates that connection failures have occurred.

Parameters

[in]

address

Address of the device to connect to

[in]

address_type

Enum gap_address_type_t. Address type of the device to connect to. Values:

  • gap_public_address (0x0): Public device address

  • gap_static_address (0x1): Static device address

  • gap_random_resolvable_address (0x2): Private resolvable random address

  • gap_random_nonresolvable_address (0x3): Private non-resolvable random address

[in]

initiating_phy

Enum gap_phy_type_t. The initiating PHY. Values:

  • gap_1m_phy (0x1): 1M PHY

  • gap_coded_phy (0x4): Coded PHY

[out]

connection

Handle that will be assigned to the connection after the connection is established. This handle is valid only if the result code of this response is 0 (zero).

Returns SL_STATUS_OK if successful. Error code otherwise. Events

  • sl_bt_evt_connection_opened - This event is triggered after the connection is opened and indicates whether the devices are already bonded and whether the role of the Bluetooth device is Slave or Master.

  • sl_bt_evt_connection_parameters - This event indicates the connection parameters and security mode of the connection.

sl_bt_connection_set_parameters()#

sl_status_t sl_bt_connection_set_parameters

(

uint8_t 

connection,

uint16_t 

min_interval,

uint16_t 

max_interval,

uint16_t 

latency,

uint16_t 

timeout,

uint16_t 

min_ce_length,

uint16_t 

max_ce_length )

Request a change in the connection parameters of a Bluetooth connection.

Parameters

[in]

connection

Connection Handle

[in]

min_interval

Minimum value for the connection event interval. This must be set less than or equal to max_interval.

  • Time = Value x 1.25 ms

  • Range: 0x0006 to 0x0c80

  • Time Range: 7.5 ms to 4 s

[in]

max_interval

Maximum value for the connection event interval. This must be set greater than or equal to min_interval.

  • Time = Value x 1.25 ms

  • Range: 0x0006 to 0x0c80

  • Time Range: 7.5 ms to 4 s

[in]

latency

Slave latency, which defines how many connection intervals the slave can skip if it has no data to send

  • Range: 0x0000 to 0x01f4

  • Use 0x0000 for default value

[in]

timeout

Supervision timeout, which defines the time that the connection is maintained although the devices can't communicate at the currently configured connection intervals.

  • Range: 0x000a to 0x0c80

  • Time = Value x 10 ms

  • Time Range: 100 ms to 32 s

  • The value in milliseconds must be larger than (1 + latency) * max_interval * 2, where max_interval is given in milliseconds. Set the supervision timeout at a value which allows communication attempts over at least a few connection intervals.

[in]

min_ce_length

Minimum value for the connection event length. This must be set less than or equal to max_ce_length. Value is not currently used and is reserved for future. Set to 0.

  • Time = Value x 0.625 ms

  • Range: 0x0000 to 0xffff

[in]

max_ce_length

Maximum value for the connection event length. This must be set greater than or equal to min_ce_length.

  • Time = Value x 0.625 ms

  • Range: 0x0000 to 0xffff

  • Use 0xffff for no limitation.

ReturnsSL_STATUS_OK if successful. Error code otherwise.

Events

sl_bt_connection_set_preferred_phy()#

sl_status_t sl_bt_connection_set_preferred_phy

(

uint8_t 

connection,

uint8_t 

preferred_phy,

uint8_t 

accepted_phy )

Sets preferred and accepted PHYs for the given connection. Event sl_bt_evt_connection_phy_status is received when PHY update procedure is completed. Non-preferred PHY can also be set if remote device does not accept any of the preferred PHYs.

The parameter accepted_phy is used for specifying the PHYs that the stack can accept in a remote initiated PHY update request. A PHY update will not occur if none of the accepted PHYs presents in the request.

NOTE: 2M and Coded PHYs are not supported by all devices.

Parameters

[in]

connection

Connection handle

[in]

preferred_phy

Preferred PHYs. This parameter is a bitfield and multiple PHYs can be set.

  • 0x01: 1M PHY

  • 0x02: 2M PHY

  • 0x04: 125k Coded PHY (S=8)

  • 0x08: 500k Coded PHY (S=2)

  • Default: 0xff (no preference)

[in]

accepted_phy

Accepted PHYs in remotely-initiated PHY update requests. This parameter is a bitfield and multiple PHYs can be set.

  • 0x01: 1M PHY

  • 0x02: 2M PHY

  • 0x04: Coded PHY

  • 0xff: Any PHYs

  • Default: 0xff (all PHYs accepted)

ReturnsSL_STATUS_OK if successful. Error code otherwise.

Events

sl_bt_connection_disable_slave_latency()#

sl_status_t sl_bt_connection_disable_slave_latency

(

uint8_t 

connection,

uint8_t 

disable )

Temporarily enable or disable slave latency. Used only when Bluetooth device is acting as slave. When slave latency is disabled, the slave latency connection parameter is not set to 0 but the device will wake up on every connection interval to receive and send packets.

Parameters

[in]

connection

Connection Handle

[in]

disable

0 enable, 1 disable slave latency. Default: 0

ReturnsSL_STATUS_OK if successful. Error code otherwise.

sl_bt_connection_get_rssi()#

sl_status_t sl_bt_connection_get_rssi

(

uint8_t 

connection

)

Get the latest RSSI value of a Bluetooth connection. The RSSI value will be reported in a sl_bt_evt_connection_rssi event.

Parameters

[in]

connection

Connection handle

ReturnsSL_STATUS_OK if successful. Error code otherwise. Events

sl_bt_connection_read_channel_map()#

sl_status_t sl_bt_connection_read_channel_map

(

uint8_t 

connection,

size_t 

max_channel_map_size,

size_t * 

channel_map_len,

uint8_t * 

channel_map )

Read channel map for a specified connection.

Parameters

[in]

connection

Connection Handle

[in]

max_channel_map_size

Size of output buffer passed in channel_map

[out]

channel_map_len

On return, set to the length of output data written to channel_map

[out]

channel_map

This parameter is 5 bytes and contains 37 1-bit fields. The nth field (in the range 0 to 36) contains the value for the link layer channel index n.* 0: Channel n is unused.

  • 1: Channel n is used.

The most significant bits are reserved for future use. |

ReturnsSL_STATUS_OK if successful. Error code otherwise.

sl_bt_connection_close()#

sl_status_t sl_bt_connection_close

(

uint8_t 

connection

)

Close a Bluetooth connection or cancel an ongoing connection establishment process. The parameter is a connection handle which is reported in sl_bt_evt_connection_opened event or sl_bt_connection_open command response.

Parameters

[in]

connection

Handle of the connection to be closed

ReturnsSL_STATUS_OK if successful. Error code otherwise. Events