1.2.2.1.2.4.12 GATTC_Write

C

uint16_t GATTC_Write(uint16_t connHandle, GATTC_WriteParams_T *p_writeParams);

GATT Client initiates a write operation to GATT Server. This API should be used to write a Characteristic Value or Characteristic descriptor.

Refer ATT opcodes (ATT_WRITE_REQ/ATT_WRITE_CMD/ATT_PREPARE_WRITE_REQ/ATT_EXECUTE_WRITE_REQ) for write types.

Write long attribute:

If the attribute is not long attribute, valueOffset should be set to 0 and writeType should be set to Write Request/Write Command as required.
If the attribute is a long attribute then first (ATT_MTU-3) bytes should be written with valueOffset set to 0 and writeType set to ATT_PREPARE_WRITE_REQ (See GATTC_WriteParams_T) in the API. The subsequent prepare write request should be called with appropriate value Offset and next set of data when event GATTC_EVT_WRITE_RESP is received. This should be repeated until expected number of bytes is queued up in the server. When event GATTC_EVT_WRITE_RESP is received for last prepare write request, this API should be called with writeType set to ATT_EXECUTE_WRITE_REQ and flags set to Execute write flag (See GATTC_WriteParams_T)

GATTC_EVT_ERROR_RESP Generated when fail to write.

GATTC_EVT_WRITE_RESP Generated when write successfully.

ATT_EVT_TIMEOUT Generated when server does not respond the request.


Parameter	Description
[in] connHandle	Handle of the connection to send write operation.
[in] p_writeParams	Pointer to the Write Request parameters. Refer GATTC_WriteParams_T.


Return value	Description
MBA_RES_SUCCESS	Successfully starts the write operation.
MBA_RES_FAIL	Operation is not permitted.
MBA_RES_OOM	Internal memory allocation failure.
MBA_RES_INVALID_PARA	Invalid parameters. One of the following reasons: - Connection handle is not valid - Invalid write parameters. See GATTC_WriteParams_T for valid values.
MBA_RES_NO_RESOURCE	No available resource to send write operation.
MBA_RES_BUSY	GATT Client is busy. Another request is ongoing.