RE: How do I add a custom characteristic value UUID.

utrank00 — Fri, 12 Jun 2015 23:56:27 GMT

Thanks!. This helps me to resolve the issue that I had.

RE: How do I add a custom characteristic value UUID.

Andreas — Wed, 10 Jun 2015 06:37:09 GMT

Good morning,

for me it works like this:

    static uint32_t custom_characteristic_char_add(ble_device_t * p_dev, const ble_device_init_t * p_dev_init)
  

{
    ble_gatts_char_md_t char_md;
    ble_gatts_attr_t    attr_char_value;
    ble_uuid_t          ble_uuid;
    ble_gatts_attr_md_t attr_md;

    memset(&char_md, 0, sizeof(char_md));

    char_md.char_props.write         = 1;
    char_md.char_props.write_wo_resp = 1;
    char_md.p_char_user_desc         = NULL;
    char_md.p_char_pf                = NULL;
    char_md.p_user_desc_md           = NULL;
    char_md.p_cccd_md                = NULL;
    char_md.p_sccd_md                = NULL;

    ble_uuid.type = p_dev->uuid_type;
    ble_uuid.uuid = BLE_CUSTOM_UUID;

    memset(&attr_md, 0, sizeof(attr_md));

    BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.read_perm);
    BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.write_perm);

    attr_md.vloc    = BLE_GATTS_VLOC_STACK;
    attr_md.rd_auth = 0;
    attr_md.wr_auth = 0;
    attr_md.vlen    = 1;

    memset(&attr_char_value, 0, sizeof(attr_char_value));

    attr_char_value.p_uuid    = &ble_uuid;
    attr_char_value.p_attr_md = &attr_md;
    attr_char_value.init_len  = 1;
    attr_char_value.init_offs = 0;
    attr_char_value.max_len   = BLE_DEVICE_MAX_CUSTOM_UUID_LEN;

    return sd_ble_gatts_characteristic_add(p_dev->service_handle,
                                           &char_md,
                                           &attr_char_value,
                                           &p_dev->customUUID_handles);
}

You will get a custom characteristic with a custio defined UUID (#define BLE_CUSTOM_UUID 0x1234).

I think this is done in the example nus_service... (UART over BLE).

Regards!