RE: How can we receive more than 20 bytes of data in NRF52 from a phone ?

Gandalf — Mon, 26 Mar 2018 12:49:48 GMT

Hi all,
I'm using s132 and SDK14.2.

I need to understand how to manage more 1 byte of data from the phone.

When I receive the event BLE_GATTS_EVT_WRITE, I call the relative function on_write() where the first code line is:

ble_gatts_evt_write_t const * p_evt_write = &p_ble_evt->evt.gatts_evt.params.write;

The structure ble_gatts_evt_write_t is the following:

/**@brief Event structure for @ref BLE_GATTS_EVT_WRITE. */
typedef struct
{
  uint16_t                    handle;             /**< Attribute Handle. */
  ble_uuid_t                  uuid;               /**< Attribute UUID. */
  uint8_t                     op;                 /**< Type of write operation, see @ref BLE_GATTS_OPS. */
  uint8_t                     auth_required;      /**< Writing operation deferred due to authorization requirement. Application may use @ref sd_ble_gatts_value_set to finalize the writing operation. */
  uint16_t                    offset;             /**< Offset for the write operation. */
  uint16_t                    len;                /**< Length of the received data. */
  /* !SG! */
  uint8_t                     data[1];            /**< Received data. @note This is a variable length array. The size of 1 indicated is only a placeholder for compilation.
                                                       See @ref sd_ble_evt_get for more information on how to use event structures with variable length array members. */
} ble_gatts_evt_write_t;

To manage more one byte, is it correct to modify the data[1] of trhis structure from 1 to X length of interest?

Thank you in advance

RE: How can we receive more than 20 bytes of data in NRF52 from a phone ?

John — Mon, 05 Mar 2018 15:04:50 GMT

As long as the phone supports BLE 4.2 you could simply make the MTU size larger to accomodate your data. If it doesn't, you probably will need to fragment the data when it is transmitted and reassemble it when the data is received in the nRF52