sd_ble_gatts_hvx returns 0x003401

[dblasco]

Hello,

I am doing a project using nRF51822, s130 and SDK 11. I have modified the example ble_ap_hrs_rscs_relay.

My problem comes when I try to update a notification in a characteristic as peripheral. I have added the char like this:

uint8_t default_value_baliza_state=0x00;
static uint32_t baliza_baliza_state_char_add(ble_baliza_t * p_baliza, const ble_baliza_init_t * p_baliza_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;
	const uint8_t user_desc[]=USER_DESC_BALIZA_STATE;
	  
    memset(&char_md, 0, sizeof(char_md));
    
    char_md.char_props.read   = 1;
    char_md.char_props.write  = 0;
	char_md.p_char_user_desc  = (uint8_t *) user_desc;
    char_md.char_user_desc_size = USER_DESC_BALIZA_STATE_LENGTH;
    char_md.char_user_desc_max_size = USER_DESC_BALIZA_STATE_LENGTH;
    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;
	char_md.char_props.notify = 1;
    
    ble_uuid.type = 0X01;
    ble_uuid.uuid = baliza_BALIZA_STATE_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_NO_ACCESS(&attr_md.write_perm);
    
	attr_md.vloc       = BLE_GATTS_VLOC_USER;
    attr_md.rd_auth    = 1;
    attr_md.wr_auth    = 1;
    attr_md.vlen       = 0;
    
    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      = 1;

    attr_char_value.p_value      = &default_value_baliza_state;
    
    return sd_ble_gatts_characteristic_add(p_baliza->service_handle, &char_md,
                                               &attr_char_value,
                                               &p_baliza->baliza_baliza_state_handles);
}

Then, when I want to update the char with the desired value, I call my function:

uint32_t ble_baliza_baliza_state_send( ble_baliza_t * p_baliza, uint8_t state)
{
	uint32_t err_code;
	if (p_baliza->conn_handle != BLE_CONN_HANDLE_INVALID)
    {
        uint16_t               len;
        ble_gatts_hvx_params_t hvx_params;

		len=1;

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

        hvx_params.handle = p_baliza->baliza_baliza_state_handles.value_handle;
        hvx_params.type   = BLE_GATT_HVX_NOTIFICATION;
        hvx_params.offset = 0;
        hvx_params.p_len  = &len;
        hvx_params.p_data = &state;

        err_code = sd_ble_gatts_hvx(p_baliza->conn_handle, &hvx_params);
		APP_ERROR_CHECK(err_code);
	}	
}

My code crashes with sd_ble_gatts_hvx with err_code=0x0003401.

Could anyone help? If more information is needed (like type definitions) please ask.

Thank you very much

[RK]

The return codes from sd_ble_gatts_hvx() are all documented, go to the resources tab at the top of the page, browse the docs, find the function and see which error code you're getting.

Hint - it has 'SYS_ATTR' in it.

[dblasco]

Found BLE_ERROR_GATTS_SYS_ATTR_MISSING (the 0x3401 confused me as i would have expected only 0x0001). As it is recommended in the documentation, I am using the function sd_ble_gatts_sys_attr_set (without luck yet, as I am not sure what should I put in the input parameters).

It is strange though that I have to do this when the exemple didn't need to...

[RK]

well if you have no saved system attributes, which you won't then you pass null, here's what the function docs say

p_sysattrs may point directly to the application's stored copy of the system attributes obtained using 
sd_ble_gatts_sys_attr_get. If the pointer is NULL, the system attribute info is initialized, assuming that
 the application does not have any previously saved system attribute data for this device.

[dblasco]

Finally I solved this using the function you told me. The sd_ble_gatts_sys_attr_get was not necessary at the end. Thank you very much