Generic Attribute Profile (gatt)

The commands and events in this class can be used to browse and manage attributes in a remote GATT server.

gatt commands

gatt_discover_characteristics

This command can be used to discover all characteristics of the defined GATT service from a remote GATT database. This command generates a unique gatt_characteristic event for every discovered characteristic. Received gatt_procedure_completed event indicates that this GATT procedure has succesfully completed or failed with error.

Command

Byte Type Name Description
0 0x20 hilen Message type: Command
1 0x05 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x03 method Message ID
4 uint8 connection Connection handle
5-8 uint32 service GATT service handle

This value is normally received from the gatt_service event.

Response

Byte Type Name Description
0 0x20 hilen Message type: Response
1 0x02 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x03 method Message ID
4-5 uint16 result Result code
  • 0: success
  • Non-zero: an error occurred
For other values refer to the Error codes

API

/* Function */
struct gecko_msg_gatt_discover_characteristics_rsp_t *gecko_cmd_gatt_discover_characteristics(uint8 connection, uint32 service);

/* Response id */
gecko_rsp_gatt_discover_characteristics_id

/* Response structure */
struct gecko_msg_gatt_discover_characteristics_rsp_t
{
  uint16 result
}

Events generated

Event Description
gatt_characteristic Discovered characteristic from remote GATT database.
gatt_procedure_completed Procedure has been successfully completed or failed with error.

gatt_discover_characteristics_by_uuid

This command can be used to discover all the characteristics of the specified GATT service in a remote GATT database having the specified UUID. This command generates a unique gatt_characteristic event for every discovered characteristic having the specified UUID. Received gatt_procedure_completed event indicates that this GATT procedure has successfully completed or failed with error.

Command

Byte Type Name Description
0 0x20 hilen Message type: Command
1 0x06 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x04 method Message ID
4 uint8 connection Connection handle
5-8 uint32 service GATT service handle

This value is normally received from the gatt_service event.

9 uint8array uuid Characteristic UUID

Response

Byte Type Name Description
0 0x20 hilen Message type: Response
1 0x02 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x04 method Message ID
4-5 uint16 result Result code
  • 0: success
  • Non-zero: an error occurred
For other values refer to the Error codes

API

/* Function */
struct gecko_msg_gatt_discover_characteristics_by_uuid_rsp_t *gecko_cmd_gatt_discover_characteristics_by_uuid(uint8 connection, uint32 service, uint8 uuid_len, const uint8 *uuid_data);

/* Response id */
gecko_rsp_gatt_discover_characteristics_by_uuid_id

/* Response structure */
struct gecko_msg_gatt_discover_characteristics_by_uuid_rsp_t
{
  uint16 result
}

Events generated

Event Description
gatt_characteristic Discovered characteristic from remote GATT database.
gatt_procedure_completed Procedure has been successfully completed or failed with error.

gatt_discover_descriptors

This command can be used to discover all the descriptors of the specified remote GATT characteristics in a remote GATT database. This command generates a unique gatt_descriptor event for every discovered descriptor. Received gatt_procedure_completed event indicates that this GATT procedure has succesfully completed or failed with error.

Command

Byte Type Name Description
0 0x20 hilen Message type: Command
1 0x03 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x06 method Message ID
4 uint8 connection Connection handle
5-6 uint16 characteristic GATT characteristic handle

This value is normally received from the gatt_characteristic event.

Response

Byte Type Name Description
0 0x20 hilen Message type: Response
1 0x02 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x06 method Message ID
4-5 uint16 result Result code
  • 0: success
  • Non-zero: an error occurred
For other values refer to the Error codes

API

/* Function */
struct gecko_msg_gatt_discover_descriptors_rsp_t *gecko_cmd_gatt_discover_descriptors(uint8 connection, uint16 characteristic);

/* Response id */
gecko_rsp_gatt_discover_descriptors_id

/* Response structure */
struct gecko_msg_gatt_discover_descriptors_rsp_t
{
  uint16 result
}

Events generated

Event Description
gatt_descriptor Discovered descriptor from remote GATT database.
gatt_procedure_completed Procedure has been successfully completed or failed with error.

gatt_discover_primary_services

This command can be used to discover all the primary services of a remote GATT database. This command generates a unique gatt_service event for every discovered primary service. Received gatt_procedure_completed event indicates that this GATT procedure has successfully completed or failed with error.

Command

Byte Type Name Description
0 0x20 hilen Message type: Command
1 0x01 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x01 method Message ID
4 uint8 connection Connection handle

Response

Byte Type Name Description
0 0x20 hilen Message type: Response
1 0x02 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x01 method Message ID
4-5 uint16 result Result code
  • 0: success
  • Non-zero: an error occurred
For other values refer to the Error codes

API

/* Function */
struct gecko_msg_gatt_discover_primary_services_rsp_t *gecko_cmd_gatt_discover_primary_services(uint8 connection);

/* Response id */
gecko_rsp_gatt_discover_primary_services_id

/* Response structure */
struct gecko_msg_gatt_discover_primary_services_rsp_t
{
  uint16 result
}

Events generated

Event Description
gatt_service Discovered service from remote GATT database
gatt_procedure_completed Procedure has been successfully completed or failed with error.

gatt_discover_primary_services_by_uuid

This command can be used to discover primary services with the specified UUID in a remote GATT database. This command generates unique gatt_service event for every discovered primary service. Received gatt_procedure_completed event indicates that this GATT procedure has succesfully completed or failed with error.

Command

Byte Type Name Description
0 0x20 hilen Message type: Command
1 0x02 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x02 method Message ID
4 uint8 connection Connection handle
5 uint8array uuid Service UUID

Response

Byte Type Name Description
0 0x20 hilen Message type: Response
1 0x02 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x02 method Message ID
4-5 uint16 result Result code
  • 0: success
  • Non-zero: an error occurred
For other values refer to the Error codes

API

/* Function */
struct gecko_msg_gatt_discover_primary_services_by_uuid_rsp_t *gecko_cmd_gatt_discover_primary_services_by_uuid(uint8 connection, uint8 uuid_len, const uint8 *uuid_data);

/* Response id */
gecko_rsp_gatt_discover_primary_services_by_uuid_id

/* Response structure */
struct gecko_msg_gatt_discover_primary_services_by_uuid_rsp_t
{
  uint16 result
}

Events generated

Event Description
gatt_service Discovered service from remote GATT database.
gatt_procedure_completed Procedure has been successfully completed or failed with error.

gatt_execute_characteristic_value_write

This command can be used to commit or cancel previously queued writes to a long characteristic of a remote GATT server. Writes are sent to queue with prepare_characteristic_value_write command. Content, offset and length of queued values are validated by this procedure. A received gatt_procedure_completed event indicates that all data has been written successfully or that an error response has been received.

Command

Byte Type Name Description
0 0x20 hilen Message type: Command
1 0x02 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x0c method Message ID
4 uint8 connection Connection handle
5 uint8 flags Unsigned 8-bit integer

Response

Byte Type Name Description
0 0x20 hilen Message type: Response
1 0x02 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x0c method Message ID
4-5 uint16 result Result code
  • 0: success
  • Non-zero: an error occurred
For other values refer to the Error codes

API

/* Function */
struct gecko_msg_gatt_execute_characteristic_value_write_rsp_t *gecko_cmd_gatt_execute_characteristic_value_write(uint8 connection, uint8 flags);

/* Response id */
gecko_rsp_gatt_execute_characteristic_value_write_id

/* Response structure */
struct gecko_msg_gatt_execute_characteristic_value_write_rsp_t
{
  uint16 result
}

Events generated

Event Description
gatt_procedure_completed Procedure has been successfully completed or failed with error.

gatt_find_included_services

This command can be used to find out if a service of a remote GATT database includes one or more other services. This command generates a unique gatt_service_completed event for each included service. This command generates a unique gatt_service event for every discovered service. Received gatt_procedure_completed event indicates that this GATT procedure has successfully completed or failed with error.

Command

Byte Type Name Description
0 0x20 hilen Message type: Command
1 0x05 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x10 method Message ID
4 uint8 connection Connection handle
5-8 uint32 service GATT service handle

This value is normally received from the gatt_service event.

Response

Byte Type Name Description
0 0x20 hilen Message type: Response
1 0x02 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x10 method Message ID
4-5 uint16 result Result code
  • 0: success
  • Non-zero: an error occurred
For other values refer to the Error codes

API

/* Function */
struct gecko_msg_gatt_find_included_services_rsp_t *gecko_cmd_gatt_find_included_services(uint8 connection, uint32 service);

/* Response id */
gecko_rsp_gatt_find_included_services_id

/* Response structure */
struct gecko_msg_gatt_find_included_services_rsp_t
{
  uint16 result
}

Events generated

Event Description
gatt_service Discovered service from remote GATT database.
gatt_procedure_completed Procedure has been successfully completed or failed with error.

gatt_prepare_characteristic_value_reliable_write

This command can be used to add a characteristic value to the write queue of a remote GATT server and verify if the value was correctly received by the server. Received gatt_procedure_completed event indicates that this GATT procedure has succesfully completed or failed with error. Specifically, error code 0x0194 (data_corrupted) will be returned if the value received from the GATT server's response failed to pass the reliable write verification. At most ATT_MTU - 5 amount of data can be sent once. Writes are executed or cancelled with the execute_characteristic_value_write command. Whether the writes succeeded or not are indicated in the response of the execute_characteristic_value_write command.

Command

Byte Type Name Description
0 0x20 hilen Message type: Command
1 0x06 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x13 method Message ID
4 uint8 connection Connection handle
5-6 uint16 characteristic GATT characteristic handle

This value is normally received from the gatt_characteristic event.

7-8 uint16 offset Offset of the characteristic value
9 uint8array value Value to write into the specified characteristic of the remote GATT database

Response

Byte Type Name Description
0 0x20 hilen Message type: Response
1 0x04 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x13 method Message ID
4-5 uint16 result Result code
  • 0: success
  • Non-zero: an error occurred
For other values refer to the Error codes
6-7 uint16 sent_len The length of data sent to the remote GATT server

API

/* Function */
struct gecko_msg_gatt_prepare_characteristic_value_reliable_write_rsp_t *gecko_cmd_gatt_prepare_characteristic_value_reliable_write(uint8 connection, uint16 characteristic, uint16 offset, uint8 value_len, const uint8 *value_data);

/* Response id */
gecko_rsp_gatt_prepare_characteristic_value_reliable_write_id

/* Response structure */
struct gecko_msg_gatt_prepare_characteristic_value_reliable_write_rsp_t
{
  uint16 result,
  uint16 sent_len
}

Events generated

Event Description
gatt_procedure_completed Procedure has been successfully completed or failed with error.

gatt_prepare_characteristic_value_write

This command can be used to add a characteristic value to the write queue of a remote GATT server. This command can be used in cases where very long attributes need to be written, or a set of values needs to be written atomically. At most ATT_MTU - 5 amount of data can be sent once. Writes are executed or cancelled with the execute_characteristic_value_write command. Whether the writes succeeded or not are indicated in the response of the execute_characteristic_value_write command.

In all cases where the amount of data to transfer fits into the BGAPI payload the command gatt_write_characteristic_value is recommended for writing long values since it transparently performs the prepare_write and execute_write commands.

Command

Byte Type Name Description
0 0x20 hilen Message type: Command
1 0x06 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x0b method Message ID
4 uint8 connection Connection handle
5-6 uint16 characteristic GATT characteristic handle

This value is normally received from the gatt_characteristic event.

7-8 uint16 offset Offset of the characteristic value
9 uint8array value Value to write into the specified characteristic of the remote GATT database

Response

Byte Type Name Description
0 0x20 hilen Message type: Response
1 0x04 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x0b method Message ID
4-5 uint16 result Result code
  • 0: success
  • Non-zero: an error occurred
For other values refer to the Error codes
6-7 uint16 sent_len The length of data sent to the remote GATT server

API

/* Function */
struct gecko_msg_gatt_prepare_characteristic_value_write_rsp_t *gecko_cmd_gatt_prepare_characteristic_value_write(uint8 connection, uint16 characteristic, uint16 offset, uint8 value_len, const uint8 *value_data);

/* Response id */
gecko_rsp_gatt_prepare_characteristic_value_write_id

/* Response structure */
struct gecko_msg_gatt_prepare_characteristic_value_write_rsp_t
{
  uint16 result,
  uint16 sent_len
}

Events generated

Event Description
gatt_procedure_completed Procedure has been successfully completed or failed with error.

gatt_read_characteristic_value

This command can be used to read the value of a characteristic from a remote GATT database. A single gatt_characteristic_value event is generated if the characteristic value fits in one ATT PDU. Otherwise more than one gatt_characteristic_value events are generated because the firmware will automatically use the "read long" GATT procedure. A received gatt_procedure_completed event indicates that all data has been read successfully or that an error response has been received.

Note that the GATT client does not verify if the requested atrribute is a characteristic value. Thus before calling this command the application should make sure the attribute handle is for a characteristic value in some means, for example, by performing characteristic discovery.

Command

Byte Type Name Description
0 0x20 hilen Message type: Command
1 0x03 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x07 method Message ID
4 uint8 connection Connection handle
5-6 uint16 characteristic GATT characteristic handle

This value is normally received from the gatt_characteristic event.

Response

Byte Type Name Description
0 0x20 hilen Message type: Response
1 0x02 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x07 method Message ID
4-5 uint16 result Result code
  • 0: success
  • Non-zero: an error occurred
For other values refer to the Error codes

API

/* Function */
struct gecko_msg_gatt_read_characteristic_value_rsp_t *gecko_cmd_gatt_read_characteristic_value(uint8 connection, uint16 characteristic);

/* Response id */
gecko_rsp_gatt_read_characteristic_value_id

/* Response structure */
struct gecko_msg_gatt_read_characteristic_value_rsp_t
{
  uint16 result
}

Events generated

Event Description
gatt_characteristic_value This event contains the data belonging to a characteristic sent by the GATT Server.
gatt_procedure_completed Procedure has been successfully completed or failed with error.

gatt_read_characteristic_value_by_uuid

This command can be used to read the characteristic value of a service from a remote GATT database by giving the UUID of the characteristic and the handle of the service containing this characteristic. A single gatt_characteristic_value event is generated if the characteristic value fits in one ATT PDU. Otherwise more than one gatt_characteristic_value events are generated because the firmware will automatically use the "read long" GATT procedure. A received gatt_procedure_completed event indicates that all data has been read successfully or that an error response has been received.

Command

Byte Type Name Description
0 0x20 hilen Message type: Command
1 0x06 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x08 method Message ID
4 uint8 connection Connection handle
5-8 uint32 service GATT service handle

This value is normally received from the gatt_service event.

9 uint8array uuid Characteristic UUID

Response

Byte Type Name Description
0 0x20 hilen Message type: Response
1 0x02 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x08 method Message ID
4-5 uint16 result Result code
  • 0: success
  • Non-zero: an error occurred
For other values refer to the Error codes

API

/* Function */
struct gecko_msg_gatt_read_characteristic_value_by_uuid_rsp_t *gecko_cmd_gatt_read_characteristic_value_by_uuid(uint8 connection, uint32 service, uint8 uuid_len, const uint8 *uuid_data);

/* Response id */
gecko_rsp_gatt_read_characteristic_value_by_uuid_id

/* Response structure */
struct gecko_msg_gatt_read_characteristic_value_by_uuid_rsp_t
{
  uint16 result
}

Events generated

Event Description
gatt_characteristic_value This event contains the data belonging to a characteristic sent by the GATT Server.
gatt_procedure_completed Procedure has been successfully completed or failed with error.

gatt_read_characteristic_value_from_offset

This command can be used to read a partial characteristic value with specified offset and maximum length from a remote GATT database. It is equivalent to gatt_read_characteristic_value if both the offset and maximum length parameters are 0. A single gatt_characteristic_value event is generated if the value to read fits in one ATT PDU. Otherwise more than one gatt_characteristic_value events are generated because the firmware will automatically use the "read long" GATT procedure. A received gatt_procedure_completed event indicates that all data has been read successfully or that an error response has been received.

Command

Byte Type Name Description
0 0x20 hilen Message type: Command
1 0x07 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x12 method Message ID
4 uint8 connection Connection handle
5-6 uint16 characteristic GATT characteristic handle

This value is normally received from the gatt_characteristic event.

7-8 uint16 offset Offset of the characteristic value
9-10 uint16 maxlen Maximum bytes to read. If this parameter is 0 all characteristic value starting at given offset will be read.

Response

Byte Type Name Description
0 0x20 hilen Message type: Response
1 0x02 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x12 method Message ID
4-5 uint16 result Result code
  • 0: success
  • Non-zero: an error occurred
For other values refer to the Error codes

API

/* Function */
struct gecko_msg_gatt_read_characteristic_value_from_offset_rsp_t *gecko_cmd_gatt_read_characteristic_value_from_offset(uint8 connection, uint16 characteristic, uint16 offset, uint16 maxlen);

/* Response id */
gecko_rsp_gatt_read_characteristic_value_from_offset_id

/* Response structure */
struct gecko_msg_gatt_read_characteristic_value_from_offset_rsp_t
{
  uint16 result
}

Events generated

Event Description
gatt_characteristic_value This event contains the data belonging to a characteristic sent by the GATT Server.
gatt_procedure_completed Procedure has been successfully completed or failed with error.

gatt_read_descriptor_value

This command can be used to read the descriptor value of a characteristic in a remote GATT database. A single gatt_descriptor_value event is generated if the descriptor value fits in one ATT PDU. Otherwise more than one gatt_descriptor_value events are generated because the firmware will automatically use the "read long" GATT procedure. A received gatt_procedure_completed event indicates that all data has been read successfully or that an error response has been received.

Command

Byte Type Name Description
0 0x20 hilen Message type: Command
1 0x03 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x0e method Message ID
4 uint8 connection Connection handle
5-6 uint16 descriptor GATT characteristic descriptor handle

Response

Byte Type Name Description
0 0x20 hilen Message type: Response
1 0x02 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x0e method Message ID
4-5 uint16 result Result code
  • 0: success
  • Non-zero: an error occurred
For other values refer to the Error codes

API

/* Function */
struct gecko_msg_gatt_read_descriptor_value_rsp_t *gecko_cmd_gatt_read_descriptor_value(uint8 connection, uint16 descriptor);

/* Response id */
gecko_rsp_gatt_read_descriptor_value_id

/* Response structure */
struct gecko_msg_gatt_read_descriptor_value_rsp_t
{
  uint16 result
}

Events generated

Event Description
gatt_descriptor_value Descriptor value received from the remote GATT server.
gatt_procedure_completed Procedure has been successfully completed or failed with error.

gatt_read_multiple_characteristic_values

This command can be used to read the values of multiple characteristics from a remote GATT database at once. gatt_characteristic_value events are generated as the values are returned by the remote GATT server. A received gatt_procedure_completed event indicates that either all data has been read successfully or that an error response has been received.

Command

Byte Type Name Description
0 0x20 hilen Message type: Command
1 0x02 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x11 method Message ID
4 uint8 connection Connection handle
5 uint8array characteristic_list Little endian encoded uint16 list of characteristics to be read.

Response

Byte Type Name Description
0 0x20 hilen Message type: Response
1 0x02 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x11 method Message ID
4-5 uint16 result Result code
  • 0: success
  • Non-zero: an error occurred
For other values refer to the Error codes

API

/* Function */
struct gecko_msg_gatt_read_multiple_characteristic_values_rsp_t *gecko_cmd_gatt_read_multiple_characteristic_values(uint8 connection, uint8 characteristic_list_len, const uint8 *characteristic_list_data);

/* Response id */
gecko_rsp_gatt_read_multiple_characteristic_values_id

/* Response structure */
struct gecko_msg_gatt_read_multiple_characteristic_values_rsp_t
{
  uint16 result
}

Events generated

Event Description
gatt_characteristic_value This event contains the data belonging to a characteristic sent by the GATT Server.
gatt_procedure_completed Procedure has been successfully completed or failed with error.

gatt_send_characteristic_confirmation

This command must be used to send a characteristic confirmation to a remote GATT server after receiving an indication. The gatt_characteristic_value_event carries the att_opcode containing handle_value_indication (0x1d) which reveals that an indication has been received and this must be confirmed with this command. Confirmation needs to be sent within 30 seconds, otherwise the GATT transactions between the client and the server are discontinued.

Command

Byte Type Name Description
0 0x20 hilen Message type: Command
1 0x01 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x0d method Message ID
4 uint8 connection Connection handle

Response

Byte Type Name Description
0 0x20 hilen Message type: Response
1 0x02 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x0d method Message ID
4-5 uint16 result Result code
  • 0: success
  • Non-zero: an error occurred
For other values refer to the Error codes

API

/* Function */
struct gecko_msg_gatt_send_characteristic_confirmation_rsp_t *gecko_cmd_gatt_send_characteristic_confirmation(uint8 connection);

/* Response id */
gecko_rsp_gatt_send_characteristic_confirmation_id

/* Response structure */
struct gecko_msg_gatt_send_characteristic_confirmation_rsp_t
{
  uint16 result
}

gatt_set_characteristic_notification

This command can be used to enable or disable the notifications and indications being sent from a remote GATT server. This procedure discovers a characteristic client configuration descriptor and writes the related configuration flags to a remote GATT database. A received gatt_procedure_completed event indicates that this GATT procedure has successfully completed or that is has failed with an error.

Command

Byte Type Name Description
0 0x20 hilen Message type: Command
1 0x04 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x05 method Message ID
4 uint8 connection Connection handle
5-6 uint16 characteristic GATT characteristic handle

This value is normally received from the gatt_characteristic event.

7 uint8 flags Characteristic client configuration flags

Response

Byte Type Name Description
0 0x20 hilen Message type: Response
1 0x02 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x05 method Message ID
4-5 uint16 result Result code
  • 0: success
  • Non-zero: an error occurred
For other values refer to the Error codes

API

/* Function */
struct gecko_msg_gatt_set_characteristic_notification_rsp_t *gecko_cmd_gatt_set_characteristic_notification(uint8 connection, uint16 characteristic, uint8 flags);

/* Response id */
gecko_rsp_gatt_set_characteristic_notification_id

/* Response structure */
struct gecko_msg_gatt_set_characteristic_notification_rsp_t
{
  uint16 result
}

Events generated

Event Description
gatt_procedure_completed Procedure has been successfully completed or failed with error.
gatt_characteristic_value If an indication or notification has been enabled for a characteristic, this event is triggered whenever an indication or notification is sent by the remote GATT server. The triggering conditions on the GATT server side are defined by an upper level, for example by a profile; so it is possible that no values are ever received, or that it may take time, depending on how the server is configured.

gatt_set_max_mtu

This command can be used to set the maximum size of ATT Message Transfer Units (MTU). If the given value is too large according to the maximum BGAPI payload size, the system will select the maximal possible value as the maximum ATT_MTU. If maximum ATT_MTU is larger than 23, MTU is exchanged automatically after a Bluetooth connection has been established.

Command

Byte Type Name Description
0 0x20 hilen Message type: Command
1 0x02 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x00 method Message ID
4-5 uint16 max_mtu Maximum size of Message Transfer Units (MTU) allowed
  • Range: 23 to 250
Default: 247

Response

Byte Type Name Description
0 0x20 hilen Message type: Response
1 0x04 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x00 method Message ID
4-5 uint16 result Result code
  • 0: success
  • Non-zero: an error occurred
For other values refer to the Error codes
6-7 uint16 max_mtu The maximum ATT_MTU selected by the system if this command succeeded

API

/* Function */
struct gecko_msg_gatt_set_max_mtu_rsp_t *gecko_cmd_gatt_set_max_mtu(uint16 max_mtu);

/* Response id */
gecko_rsp_gatt_set_max_mtu_id

/* Response structure */
struct gecko_msg_gatt_set_max_mtu_rsp_t
{
  uint16 result,
  uint16 max_mtu
}

gatt_write_characteristic_value

This command can be used to write the value of a characteristic in a remote GATT database. If the given value does not fit in one ATT PDU, "write long" GATT procedure is used automatically. Received gatt_procedure_completed event indicates that all data has been written successfully or that an error response has been received.

Command

Byte Type Name Description
0 0x20 hilen Message type: Command
1 0x04 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x09 method Message ID
4 uint8 connection Connection handle
5-6 uint16 characteristic GATT characteristic handle

This value is normally received from the gatt_characteristic event.

7 uint8array value Characteristic value

Response

Byte Type Name Description
0 0x20 hilen Message type: Response
1 0x02 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x09 method Message ID
4-5 uint16 result Result code
  • 0: success
  • Non-zero: an error occurred
For other values refer to the Error codes

API

/* Function */
struct gecko_msg_gatt_write_characteristic_value_rsp_t *gecko_cmd_gatt_write_characteristic_value(uint8 connection, uint16 characteristic, uint8 value_len, const uint8 *value_data);

/* Response id */
gecko_rsp_gatt_write_characteristic_value_id

/* Response structure */
struct gecko_msg_gatt_write_characteristic_value_rsp_t
{
  uint16 result
}

Events generated

Event Description
gatt_procedure_completed Procedure has been successfully completed or failed with error.

gatt_write_characteristic_value_without_response

This command can be used to write the value of a characteristic in a remote GATT server. This command does not generate any event. All failures on the server are ignored silently. For example, if an error is generated in the remote GATT server and the given value is not written into database no error message will be reported to the local GATT client. Note that this command cannot be used to write long values. At most ATT_MTU - 3 amount of data can be sent once.

Command

Byte Type Name Description
0 0x20 hilen Message type: Command
1 0x04 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x0a method Message ID
4 uint8 connection Connection handle
5-6 uint16 characteristic GATT characteristic handle

This value is normally received from the gatt_characteristic event.

7 uint8array value Characteristic value

Response

Byte Type Name Description
0 0x20 hilen Message type: Response
1 0x04 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x0a method Message ID
4-5 uint16 result Result code
  • 0: success
  • Non-zero: an error occurred
For other values refer to the Error codes
6-7 uint16 sent_len The length of data sent to the remote GATT server

API

/* Function */
struct gecko_msg_gatt_write_characteristic_value_without_response_rsp_t *gecko_cmd_gatt_write_characteristic_value_without_response(uint8 connection, uint16 characteristic, uint8 value_len, const uint8 *value_data);

/* Response id */
gecko_rsp_gatt_write_characteristic_value_without_response_id

/* Response structure */
struct gecko_msg_gatt_write_characteristic_value_without_response_rsp_t
{
  uint16 result,
  uint16 sent_len
}

gatt_write_descriptor_value

This command can be used to write the value of a characteristic descriptor in a remote GATT database. If the given value does not fit in one ATT PDU, "write long" GATT procedure is used automatically. Received gatt_procedure_completed event indicates that all data has been written succesfully or that an error response has been received.

Command

Byte Type Name Description
0 0x20 hilen Message type: Command
1 0x04 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x0f method Message ID
4 uint8 connection Connection handle
5-6 uint16 descriptor GATT characteristic descriptor handle
7 uint8array value Descriptor value

Response

Byte Type Name Description
0 0x20 hilen Message type: Response
1 0x02 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x0f method Message ID
4-5 uint16 result Result code
  • 0: success
  • Non-zero: an error occurred
For other values refer to the Error codes

API

/* Function */
struct gecko_msg_gatt_write_descriptor_value_rsp_t *gecko_cmd_gatt_write_descriptor_value(uint8 connection, uint16 descriptor, uint8 value_len, const uint8 *value_data);

/* Response id */
gecko_rsp_gatt_write_descriptor_value_id

/* Response structure */
struct gecko_msg_gatt_write_descriptor_value_rsp_t
{
  uint16 result
}

Events generated

Event Description
gatt_procedure_completed Procedure has been successfully completed or failed with error.

gatt events

gatt_mtu_exchanged

This event indicates that an ATT_MTU exchange procedure has been completed. Parameter mtu describes new MTU size. MTU size 23 is used before this event is received.

Event

Byte Type Name Description
0 0xa0 hilen Message type: Event
1 0x03 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x00 method Message ID
4 uint8 connection Connection handle
5-6 uint16 mtu Exchanged ATT_MTU

API

/* event id*/
gecko_evt_gatt_mtu_exchanged_id

/* event structure*/
struct gecko_msg_gatt_mtu_exchanged_evt_t
{
  uint8 connection,
  uint16 mtu
}

gatt_service

This event indicates that a GATT service in the remote GATT database was discovered. This event is generated after issuing either the gatt_discover_primary_services or gatt_discover_primary_services_by_uuid command.

Event

Byte Type Name Description
0 0xa0 hilen Message type: Event
1 0x06 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x01 method Message ID
4 uint8 connection Connection handle
5-8 uint32 service GATT service handle
9 uint8array uuid Service UUID

API

/* event id*/
gecko_evt_gatt_service_id

/* event structure*/
struct gecko_msg_gatt_service_evt_t
{
  uint8 connection,
  uint32 service,
  uint8array uuid
}

gatt_characteristic

This event indicates that a GATT characteristic in the remote GATT database was discovered. This event is generated after issuing either the gatt_discover_characteristics or gatt_discover_characteristics_by_uuid command.

Event

Byte Type Name Description
0 0xa0 hilen Message type: Event
1 0x05 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x02 method Message ID
4 uint8 connection Connection handle
5-6 uint16 characteristic GATT characteristic handle
7 uint8 properties Characteristic properties
8 uint8array uuid Characteristic UUID

API

/* event id*/
gecko_evt_gatt_characteristic_id

/* event structure*/
struct gecko_msg_gatt_characteristic_evt_t
{
  uint8 connection,
  uint16 characteristic,
  uint8 properties,
  uint8array uuid
}

gatt_descriptor

This event indicates that a GATT characteristic descriptor in the remote GATT database was discovered. This event is generated after issuing the gatt_discover_descriptors command.

Event

Byte Type Name Description
0 0xa0 hilen Message type: Event
1 0x04 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x03 method Message ID
4 uint8 connection Connection handle
5-6 uint16 descriptor GATT characteristic descriptor handle
7 uint8array uuid Descriptor UUID

API

/* event id*/
gecko_evt_gatt_descriptor_id

/* event structure*/
struct gecko_msg_gatt_descriptor_evt_t
{
  uint8 connection,
  uint16 descriptor,
  uint8array uuid
}

gatt_characteristic_value

This event indicates that the value of a characteristic in the remote GATT server was received. This event is triggered as a result of several commands: gatt_read_characteristic_value, gatt_read_characteristic_value_from_offset, gatt_read_characteristic_value_by_uuid, gatt_read_multiple_characteristic_values; and when the remote GATT server sends indications or notifications after enabling notifications with gatt_set_characteristic_notification. The parameter att_opcode reveals which type of GATT transaction triggered this event. In particular, if the att_opcode type is handle_value_indication (0x1d), the application needs to confirm the indication with gatt_send_characteristic_confirmation.

Event

Byte Type Name Description
0 0xa0 hilen Message type: Event
1 0x07 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x04 method Message ID
4 uint8 connection Connection handle
5-6 uint16 characteristic GATT characteristic handle

This value is normally received from the gatt_characteristic event.

7 uint8 att_opcode Attribute opcode which informs the GATT transaction used
8-9 uint16 offset Value offset
10 uint8array value Characteristic value

API

/* event id*/
gecko_evt_gatt_characteristic_value_id

/* event structure*/
struct gecko_msg_gatt_characteristic_value_evt_t
{
  uint8 connection,
  uint16 characteristic,
  uint8 att_opcode,
  uint16 offset,
  uint8array value
}

gatt_descriptor_value

This event indicates that the value of a descriptor in the remote GATT server was received. This event is generated by the gatt_read_descriptor_value command.

Event

Byte Type Name Description
0 0xa0 hilen Message type: Event
1 0x06 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x05 method Message ID
4 uint8 connection Connection handle
5-6 uint16 descriptor GATT characteristic descriptor handle
7-8 uint16 offset Value offset
9 uint8array value Descriptor value

API

/* event id*/
gecko_evt_gatt_descriptor_value_id

/* event structure*/
struct gecko_msg_gatt_descriptor_value_evt_t
{
  uint8 connection,
  uint16 descriptor,
  uint16 offset,
  uint8array value
}

gatt_procedure_completed

This event indicates that the current GATT procedure has been completed successfully or that it has failed with an error. All GATT commands excluding gatt_write_characteristic_value_without_response and gatt_send_characteristic_confirmation will trigger this event, so the application must wait for this event before issuing another GATT command (excluding the two aforementioned exceptions).

Event

Byte Type Name Description
0 0xa0 hilen Message type: Event
1 0x03 lolen Minimum payload length
2 0x09 class Message class:Generic Attribute Profile
3 0x06 method Message ID
4 uint8 connection Connection handle
5-6 uint16 result Result code
  • 0: success
  • Non-zero: an error occurred
For other values refer to the Error codes

API

/* event id*/
gecko_evt_gatt_procedure_completed_id

/* event structure*/
struct gecko_msg_gatt_procedure_completed_evt_t
{
  uint8 connection,
  uint16 result
}

gatt enumerations

gatt_att_opcode

These values indicate which attribute request or response has caused the event.

Enumerations

Value Name Description
8 gatt_read_by_type_request Read by type request
9 gatt_read_by_type_response Read by type response
10 gatt_read_request Read request
11 gatt_read_response Read response
12 gatt_read_blob_request Read blob request
13 gatt_read_blob_response Read blob response
14 gatt_read_multiple_request Read multiple request
15 gatt_read_multiple_response Read multiple response
18 gatt_write_request Write request
19 gatt_write_response Write response
82 gatt_write_command Write command
22 gatt_prepare_write_request Prepare write request
23 gatt_prepare_write_response Prepare write response
24 gatt_execute_write_request Execute write request
25 gatt_execute_write_response Execute write response
27 gatt_handle_value_notification Notification
29 gatt_handle_value_indication Indication

gatt_client_config_flag

These values define whether the client is to receive notifications or indications from a remote GATT server.

Enumerations

Value Name Description
0 gatt_disable Disable notifications and indications
1 gatt_notification Notification
2 gatt_indication Indication

gatt_execute_write_flag

These values define whether the GATT server is to cancel all queued writes or commit all queued writes to a remote database.

Enumerations

Value Name Description
0 gatt_cancel Cancel all queued writes
1 gatt_commit Commit all queued writes