Hello! I am trying to send a notification to a peer device when a certain event occurs. To do so, I'm using the same procedure as with every other characteristic with enabled notifications.
void init_buffer_status_char(){
uint32_t err_code=0;
ble_uuid_t char_uuid;
char_uuid.uuid = BLE_UUID_BUFFER_STATUS_CHARACTERISTC_UUID;
ble_uuid128_t base_uuid = BLE_UUID_OUR_BASE_UUID;
err_code = sd_ble_uuid_vs_add(&base_uuid, &char_uuid.type);
APP_ERROR_CHECK(err_code);
//Attribute metadata
ble_gatts_attr_md_t attr_md;
memset(&attr_md, 0, sizeof(attr_md));
attr_md.vlen = 1;
attr_md.vloc = BLE_GATTS_VLOC_USER;
BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.read_perm);
BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.write_perm);
//Characteristic metadata
ble_gatts_attr_md_t cccd_md;
memset(&cccd_md, 0, sizeof(cccd_md));
BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.read_perm);
BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.write_perm);
cccd_md.vloc = BLE_GATTS_VLOC_STACK;
ble_gatts_char_md_t char_md;
memset(&char_md, 0, sizeof(char_md));
char_md.char_props.read = 1;
char_md.char_props.write = 1;
char_md.char_props.notify = 1;
char_md.p_cccd_md = &cccd_md;
//Characteristic value
ble_gatts_attr_t attr_char_value;
memset(&attr_char_value, 0, sizeof(attr_char_value));
attr_char_value.p_uuid = &char_uuid;
attr_char_value.p_attr_md = &attr_md;
attr_char_value.max_len = 1;
attr_char_value.init_len = 1;
attr_char_value.p_value = buffer_status_char_value;
err_code = sd_ble_gatts_characteristic_add(ble_struct.status_service_handle, &char_md, &attr_char_value, &ble_struct.buffer_status_char_handle);
APP_ERROR_CHECK(err_code);
}
However, when the notification function is ran, 0x3401 error occurs. According to documenttion that error is BLE_ERROR_GATTS_SYS_ATTR_MISSING. What may be causing this? When I connect with the nRF Master Control I can see the characteristic and its value, so does exist.
void notify_buffer_status(uint8_t status){
int i=0;
uint32_t err_code;
buffer_status_char_value[0] = status;
if (ble_struct.conn_handle != BLE_CONN_HANDLE_INVALID){
uint16_t len = 1;
ble_gatts_hvx_params_t hvx_params;
memset(&hvx_params, 0, sizeof(hvx_params));
hvx_params.handle = ble_struct.buffer_status_char_handle.value_handle;
hvx_params.type = BLE_GATT_HVX_NOTIFICATION;
hvx_params.offset = 0;
hvx_params.p_len = &len;
hvx_params.p_data = buffer_status_char_value;
if((err_code = sd_ble_gatts_hvx(ble_struct.conn_handle, &hvx_params)) != NRF_SUCCESS)
SEGGER_RTT_printf(0, "Notification failed code: %d\n", err_code);
else
SEGGER_RTT_printf(0, "Sent notification\n");
}
else
SEGGER_RTT_printf(0, "No connection.\n");
}
