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Service Notification problem - BLE_ERROR_INVALID_ATTR_HANDLE

Hello everyone,

I am trying to enable notification on a characteristic based on the code example from nAN36. Unfortunately the sd_ble_gatts_hvx() function returns:

BLE_ERROR_INVALID_ATTR_HANDLE - "Invalid attribute handle(s) supplied. Only attributes added directly by the application are available to notify and indicate."

I can't quite get the meaning of the "attributes added directly by the application". Any ideas how to interpret that or general guidelines how to approach this problem?

The setup is: ARMGCC + S110 + 51822. I am testing it with the nRF Master Control Panel, where it says that the notifications are enabled.

Thank you in advance!

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0 GT over 8 years ago

Hello Petter, Thank you for the answer. However I am still having troubles with BLE_ERROR_INVALID_ATTR_HANDLE when I try to check if the notify/indicate is enabled.

This is how the characteristic is added to the service:

	    ble_gatts_char_md_t char_md;
    ble_gatts_attr_md_t cccd_md;
    ble_gatts_attr_t    attr_char_value;
    ble_uuid_t          ble_uuid;
    ble_gatts_attr_md_t attr_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;

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

    char_md.char_props.read   = 1;
    char_md.char_props.notify = 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         = &cccd_md;
    char_md.p_sccd_md         = NULL;

    ble_uuid.type = p_lbs->uuid_type;
    ble_uuid.uuid = LBS_UUID_BUTTON_CHAR;

    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_STACK;
    attr_md.rd_auth    = 0;
    attr_md.wr_auth    = 0;
    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     = sizeof(uint8_t);
    attr_char_value.init_offs    = 0;
    attr_char_value.max_len      = sizeof(uint8_t);
    attr_char_value.p_value      = NULL;

    return sd_ble_gatts_characteristic_add(p_lbs->service_handle, &char_md,
                                               &attr_char_value,
                                               &p_lbs->button_char_handles);

This is what happens whne the button gets pressed:

uint32_t err_code;
ble_gatts_hvx_params_t params;
uint16_t len = sizeof(button_state);

memset(&params, 0, sizeof(params));
params.type = BLE_GATT_HVX_NOTIFICATION;
params.handle = p_lbs->button_char_handles.value_handle;
params.p_data = &button_state;
params.p_len = &len;

err_code = sd_ble_gatts_hvx(p_lbs->conn_handle, &params);

Is it correct to add "button_char_handles" and later try to notify on "params.handle = p_lbs->button_char_handles.value_handle"?

Any input will be highly appreciated. Thanks!

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