SPP API

Application Examples

  • bluetooth/bluedroid/classic_bt/bt_spp_acceptor demonstrates how to use Bluetooth capabilities to create a Serial Port Protocol (SPP) acceptor that acts as a server and integrate Secure Simple Pairing (SSP). This example also includes a demo for communicating with an SPP initiator that acts as a client.

  • bluetooth/bluedroid/classic_bt/bt_spp_initiator demonstrates how to use Bluetooth capabilities to create an SPP initiator that performs as a client and integrate SSP. This example also includes a demo for communicating with an SPP acceptor that acts as a server.

  • bluetooth/bluedroid/classic_bt/bt_spp_vfs_initiator demonstrates how to use SPP APIs to create an SPP initiator that acts as a client and communicates with an SPP acceptor, using Virtual File System (VFS) interface to send and receive data.

API Reference

Header File

  • components/bt/host/bluedroid/api/include/api/esp_spp_api.h

  • This header file can be included with:

    #include "esp_spp_api.h"

  • This header file is a part of the API provided by the bt component. To declare that your component depends on bt, add the following to your CMakeLists.txt:

    REQUIRES bt

    or

    PRIV_REQUIRES bt

Functions

esp_err_t esp_spp_register_callback(esp_spp_cb_t callback)

This function is called to init callbacks with SPP module.

参数:

callback -- [in] pointer to the init callback function.

返回:

  • ESP_OK: success

  • other: failed

esp_err_t esp_spp_enhanced_init(const esp_spp_cfg_t *cfg)

This function is called to init SPP module. When the operation is completed, the callback function will be called with ESP_SPP_INIT_EVT. This function should be called after esp_bluedroid_enable() completes successfully.

备注

The member variable enable_l2cap_etrm in esp_spp_cfg_t can affect all L2CAP channel configurations of the upper layer RFCOMM protocol.

参数:

cfg -- [in] SPP configuration.

返回:

  • ESP_OK: success

  • other: failed

esp_err_t esp_spp_deinit(void)

This function is called to uninit SPP module. The operation will close all active SPP connection first, then the callback function will be called with ESP_SPP_CLOSE_EVT, and the number of ESP_SPP_CLOSE_EVT is equal to the number of connection. When the operation is completed, the callback function will be called with ESP_SPP_UNINIT_EVT. This function should be called after esp_spp_enhanced_init() completes successfully.

返回:

  • ESP_OK: success

  • other: failed

esp_err_t esp_spp_start_discovery(esp_bd_addr_t bd_addr)

This function is called to performs service discovery for the services provided by the given peer device. When the operation is completed, the callback function will be called with ESP_SPP_DISCOVERY_COMP_EVT. This function must be called after esp_spp_enhanced_init() successful and before esp_spp_deinit().

参数:

bd_addr -- [in] Remote device bluetooth device address.

返回:

  • ESP_OK: success

  • other: failed

esp_err_t esp_spp_connect(esp_spp_sec_t sec_mask, esp_spp_role_t role, uint8_t remote_scn, esp_bd_addr_t peer_bd_addr)

This function makes an SPP connection to a remote BD Address. When the connection is initiated or failed to initiate, the callback is called with ESP_SPP_CL_INIT_EVT. When the connection is established or failed, the callback is called with ESP_SPP_OPEN_EVT. This function must be called after esp_spp_enhanced_init() successful and before esp_spp_deinit().

参数:

  • sec_mask -- [in] Security Setting Mask. Suggest to use ESP_SPP_SEC_NONE, ESP_SPP_SEC_AUTHORIZE or ESP_SPP_SEC_AUTHENTICATE only.

  • role -- [in] Master or slave.

  • remote_scn -- [in] Remote device bluetooth device SCN.

  • peer_bd_addr -- [in] Remote device bluetooth device address.

返回:

  • ESP_OK: success

  • other: failed

esp_err_t esp_spp_disconnect(uint32_t handle)

This function closes an SPP connection. When the operation is completed, the callback function will be called with ESP_SPP_CLOSE_EVT. This function must be called after esp_spp_enhanced_init() successful and before esp_spp_deinit().

参数:

handle -- [in] The connection handle.

返回:

  • ESP_OK: success

  • other: failed

esp_err_t esp_spp_start_srv(esp_spp_sec_t sec_mask, esp_spp_role_t role, uint8_t local_scn, const char *name)

This function create a SPP server and starts listening for an SPP connection request from a remote Bluetooth device. When the server is started successfully, the callback is called with ESP_SPP_START_EVT. When the connection is established, the callback is called with ESP_SPP_SRV_OPEN_EVT. This function must be called after esp_spp_enhanced_init() successful and before esp_spp_deinit().

参数:

  • sec_mask -- [in] Security Setting Mask. Suggest to use ESP_SPP_SEC_NONE, ESP_SPP_SEC_AUTHORIZE or ESP_SPP_SEC_AUTHENTICATE only.

  • role -- [in] Master or slave.

  • local_scn -- [in] The specific channel you want to get. If channel is 0, means get any channel.

  • name -- [in] Server's name.

返回:

  • ESP_OK: success

  • other: failed

esp_err_t esp_spp_stop_srv(void)

This function stops all SPP servers. The operation will close all active SPP connection first, then the callback function will be called with ESP_SPP_CLOSE_EVT, and the number of ESP_SPP_CLOSE_EVT is equal to the number of connection. When the operation is completed, the callback is called with ESP_SPP_SRV_STOP_EVT. This function must be called after esp_spp_enhanced_init() successful and before esp_spp_deinit().

返回:

  • ESP_OK: success

  • other: failed

esp_err_t esp_spp_stop_srv_scn(uint8_t scn)

This function stops a specific SPP server. The operation will close all active SPP connection first on the specific SPP server, then the callback function will be called with ESP_SPP_CLOSE_EVT, and the number of ESP_SPP_CLOSE_EVT is equal to the number of connection. When the operation is completed, the callback is called with ESP_SPP_SRV_STOP_EVT. This function must be called after esp_spp_enhanced_init() successful and before esp_spp_deinit().

参数:

scn -- [in] Server channel number.

返回:

  • ESP_OK: success

  • other: failed

esp_err_t esp_spp_write(uint32_t handle, int len, uint8_t *p_data)

This function is used to write data, only for ESP_SPP_MODE_CB. When this function need to be called repeatedly, it is strongly recommended to call this function again after the previous event ESP_SPP_WRITE_EVT is received and the parameter 'cong' is equal to false. If the previous event ESP_SPP_WRITE_EVT with parameter 'cong' is equal to true, the function can only be called again when the event ESP_SPP_CONG_EVT with parameter 'cong' equal to false is received. This function must be called after an connection between initiator and acceptor has been established.

参数:

  • handle -- [in] The connection handle.

  • len -- [in] The length of the data written.

  • p_data -- [in] The data written.

返回:

  • ESP_OK: success

  • other: failed

esp_err_t esp_spp_vfs_register(void)

This function is used to register VFS. For now, SPP only supports write, read and close. When the operation is completed, the callback function will be called with ESP_SPP_VFS_REGISTER_EVT. This function must be called after esp_spp_enhanced_init() successful and before esp_spp_deinit().

返回:

  • ESP_OK: success

  • other: failed

esp_err_t esp_spp_vfs_unregister(void)

This function is used to unregister VFS. When the operation is completed, the callback function will be called with ESP_SPP_VFS_UNREGISTER_EVT. This function must be called after esp_spp_vfs_register() successful and before esp_spp_deinit().

返回:

  • ESP_OK: success

  • other: failed

esp_err_t esp_spp_get_profile_status(esp_spp_profile_status_t *profile_status)

This function is used to get the status of SPP.

参数:

profile_status -- [out] - SPP status

返回:

  • ESP_OK: success

  • other: failed

Unions

union esp_spp_cb_param_t
#include <esp_spp_api.h>

SPP callback parameters union.

Public Members

struct esp_spp_cb_param_t::spp_init_evt_param init

SPP callback param of SPP_INIT_EVT

struct esp_spp_cb_param_t::spp_uninit_evt_param uninit

SPP callback param of SPP_UNINIT_EVT

struct esp_spp_cb_param_t::spp_discovery_comp_evt_param disc_comp

SPP callback param of SPP_DISCOVERY_COMP_EVT

struct esp_spp_cb_param_t::spp_open_evt_param open

SPP callback param of ESP_SPP_OPEN_EVT

struct esp_spp_cb_param_t::spp_srv_open_evt_param srv_open

SPP callback param of ESP_SPP_SRV_OPEN_EVT

struct esp_spp_cb_param_t::spp_close_evt_param close

SPP callback param of ESP_SPP_CLOSE_EVT

struct esp_spp_cb_param_t::spp_start_evt_param start

SPP callback param of ESP_SPP_START_EVT

struct esp_spp_cb_param_t::spp_srv_stop_evt_param srv_stop

SPP callback param of ESP_SPP_SRV_STOP_EVT

struct esp_spp_cb_param_t::spp_cl_init_evt_param cl_init

SPP callback param of ESP_SPP_CL_INIT_EVT

struct esp_spp_cb_param_t::spp_write_evt_param write

SPP callback param of ESP_SPP_WRITE_EVT

struct esp_spp_cb_param_t::spp_data_ind_evt_param data_ind

SPP callback param of ESP_SPP_DATA_IND_EVT

struct esp_spp_cb_param_t::spp_cong_evt_param cong

SPP callback param of ESP_SPP_CONG_EVT

struct esp_spp_cb_param_t::spp_vfs_register_evt_param vfs_register

SPP callback param of ESP_SPP_VFS_REGISTER_EVT

struct esp_spp_cb_param_t::spp_vfs_unregister_evt_param vfs_unregister

SPP callback param of ESP_SPP_VFS_UNREGISTER_EVT

struct spp_cl_init_evt_param
#include <esp_spp_api.h>

ESP_SPP_CL_INIT_EVT.

Public Members

esp_spp_status_t status

status

uint32_t handle

The connection handle

uint8_t sec_id

security ID used by this server

bool use_co

TRUE to use co_rfc_data

struct spp_close_evt_param
#include <esp_spp_api.h>

ESP_SPP_CLOSE_EVT.

Public Members

esp_spp_status_t status

status

uint32_t port_status

PORT status

uint32_t handle

The connection handle

bool async

FALSE, if local initiates disconnect

struct spp_cong_evt_param
#include <esp_spp_api.h>

ESP_SPP_CONG_EVT.

Public Members

esp_spp_status_t status

status

uint32_t handle

The connection handle

bool cong

TRUE, congested. FALSE, uncongested

struct spp_data_ind_evt_param
#include <esp_spp_api.h>

ESP_SPP_DATA_IND_EVT.

Public Members

esp_spp_status_t status

status

uint32_t handle

The connection handle

uint16_t len

The length of data

uint8_t *data

The data received

struct spp_discovery_comp_evt_param
#include <esp_spp_api.h>

SPP_DISCOVERY_COMP_EVT.

Public Members

esp_spp_status_t status

status

uint8_t scn_num

The num of scn_num

uint8_t scn[ESP_SPP_MAX_SCN]

channel #

const char *service_name[ESP_SPP_MAX_SCN]

service_name

struct spp_init_evt_param
#include <esp_spp_api.h>

SPP_INIT_EVT.

Public Members

esp_spp_status_t status

status

struct spp_open_evt_param
#include <esp_spp_api.h>

ESP_SPP_OPEN_EVT.

Public Members

esp_spp_status_t status

status

uint32_t handle

The connection handle

int fd

The file descriptor only for ESP_SPP_MODE_VFS

esp_bd_addr_t rem_bda

The peer address

struct spp_srv_open_evt_param
#include <esp_spp_api.h>

ESP_SPP_SRV_OPEN_EVT.

Public Members

esp_spp_status_t status

status

uint32_t handle

The connection handle

uint32_t new_listen_handle

The new listen handle

int fd

The file descriptor only for ESP_SPP_MODE_VFS

esp_bd_addr_t rem_bda

The peer address

struct spp_srv_stop_evt_param
#include <esp_spp_api.h>

ESP_SPP_SRV_STOP_EVT.

Public Members

esp_spp_status_t status

status

uint8_t scn

Server channel number

struct spp_start_evt_param
#include <esp_spp_api.h>

ESP_SPP_START_EVT.

Public Members

esp_spp_status_t status

status

uint32_t handle

The connection handle

uint8_t sec_id

security ID used by this server

uint8_t scn

Server channel number

bool use_co

TRUE to use co_rfc_data

struct spp_uninit_evt_param
#include <esp_spp_api.h>

SPP_UNINIT_EVT.

Public Members

esp_spp_status_t status

status

struct spp_vfs_register_evt_param
#include <esp_spp_api.h>

ESP_SPP_VFS_REGISTER_EVT.

Public Members

esp_spp_status_t status

status

struct spp_vfs_unregister_evt_param
#include <esp_spp_api.h>

ESP_SPP_VFS_UNREGISTER_EVT.

Public Members

esp_spp_status_t status

status

struct spp_write_evt_param
#include <esp_spp_api.h>

ESP_SPP_WRITE_EVT.

Public Members

esp_spp_status_t status

status

uint32_t handle

The connection handle

int len

The length of the data written.

bool cong

congestion status

Structures

struct esp_spp_cfg_t

SPP configuration parameters.

Public Members

esp_spp_mode_t mode

Choose the mode of SPP, ESP_SPP_MODE_CB or ESP_SPP_MODE_VFS.

bool enable_l2cap_ertm

Enable/disable Logical Link Control and Adaptation Layer Protocol enhanced retransmission mode.

uint16_t tx_buffer_size

Tx buffer size for a new SPP channel. A smaller setting can save memory, but may incur a decrease in throughput. Only for ESP_SPP_MODE_VFS mode.

struct esp_spp_profile_status_t

SPP profile status parameters.

Public Members

bool spp_inited

spp initialization

uint8_t conn_num

Number of connections

Macros

ESP_SPP_MAX_MTU

SPP max MTU

ESP_SPP_MAX_SCN

SPP max SCN

ESP_SPP_MIN_TX_BUFFER_SIZE

SPP min tx buffer

ESP_SPP_MAX_TX_BUFFER_SIZE

SPP max tx buffer size

BT_SPP_DEFAULT_CONFIG()

SPP default configuration.

ESP_SPP_SEC_NONE

No security. relate to BTA_SEC_NONE in bta/bta_api.h

ESP_SPP_SEC_AUTHORIZE

Authorization required (only needed for out going connection ) relate to BTA_SEC_AUTHORIZE in bta/bta_api.h

ESP_SPP_SEC_AUTHENTICATE

Authentication required. relate to BTA_SEC_AUTHENTICATE in bta/bta_api.h

ESP_SPP_SEC_ENCRYPT

Encryption required. relate to BTA_SEC_ENCRYPT in bta/bta_api.h

ESP_SPP_SEC_MODE4_LEVEL4

Mode 4 level 4 service, i.e. incoming/outgoing MITM and P-256 encryption relate to BTA_SEC_MODE4_LEVEL4 in bta/bta_api.h

ESP_SPP_SEC_MITM

Man-In-The_Middle protection relate to BTA_SEC_MITM in bta/bta_api.h

ESP_SPP_SEC_IN_16_DIGITS

Min 16 digit for pin code relate to BTA_SEC_IN_16_DIGITS in bta/bta_api.h

Type Definitions

typedef uint16_t esp_spp_sec_t
typedef void (*esp_spp_cb_t)(esp_spp_cb_event_t event, esp_spp_cb_param_t *param)

SPP callback function type. When handle ESP_SPP_DATA_IND_EVT, it is strongly recommended to cache incoming data, and process them in other lower priority application task rather than in this callback directly.

Param event:

Event type

Param param:

Point to callback parameter, currently is union type

Enumerations

enum esp_spp_status_t

Values:

enumerator ESP_SPP_SUCCESS

Successful operation.

enumerator ESP_SPP_FAILURE

Generic failure.

enumerator ESP_SPP_BUSY

Temporarily can not handle this request.

enumerator ESP_SPP_NO_DATA

No data

enumerator ESP_SPP_NO_RESOURCE

No more resource

enumerator ESP_SPP_NEED_INIT

SPP module shall init first

enumerator ESP_SPP_NEED_DEINIT

SPP module shall deinit first

enumerator ESP_SPP_NO_CONNECTION

Connection may have been closed

enumerator ESP_SPP_NO_SERVER

No SPP server

enum esp_spp_role_t

Values:

enumerator ESP_SPP_ROLE_MASTER

Role: master

enumerator ESP_SPP_ROLE_SLAVE

Role: slave

enum esp_spp_mode_t

Values:

enumerator ESP_SPP_MODE_CB

When data is coming, a callback will come with data

enumerator ESP_SPP_MODE_VFS

Use VFS to write/read data

enum esp_spp_cb_event_t

SPP callback function events.

Values:

enumerator ESP_SPP_INIT_EVT

When SPP is initialized, the event comes

enumerator ESP_SPP_UNINIT_EVT

When SPP is deinitialized, the event comes

enumerator ESP_SPP_DISCOVERY_COMP_EVT

When SDP discovery complete, the event comes

enumerator ESP_SPP_OPEN_EVT

When SPP Client connection open, the event comes

enumerator ESP_SPP_CLOSE_EVT

When SPP connection closed, the event comes

enumerator ESP_SPP_START_EVT

When SPP server started, the event comes

enumerator ESP_SPP_CL_INIT_EVT

When SPP client initiated a connection, the event comes

enumerator ESP_SPP_DATA_IND_EVT

When SPP connection received data, the event comes, only for ESP_SPP_MODE_CB

enumerator ESP_SPP_CONG_EVT

When SPP connection congestion status changed, the event comes, only for ESP_SPP_MODE_CB

enumerator ESP_SPP_WRITE_EVT

When SPP write operation completes, the event comes, only for ESP_SPP_MODE_CB

enumerator ESP_SPP_SRV_OPEN_EVT

When SPP Server connection open, the event comes

enumerator ESP_SPP_SRV_STOP_EVT

When SPP server stopped, the event comes

enumerator ESP_SPP_VFS_REGISTER_EVT

When SPP VFS register, the event comes

enumerator ESP_SPP_VFS_UNREGISTER_EVT

When SPP VFS unregister, the event comes

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