nRF52840 - sd_ble_gattc_exchange_mtu_request() returned NRF_ERROR_INVALID_PARAM.

RE: nRF52840 - sd_ble_gattc_exchange_mtu_request() returned NRF_ERROR_INVALID_PARAM.

MartinBL — Fri, 19 Oct 2018 14:48:33 GMT

That is great news! Very strange though. I can't remember seeing anything like it before, and I have no idea what it could have been.

Have nice weekend.

-Martin

RE: nRF52840 - sd_ble_gattc_exchange_mtu_request() returned NRF_ERROR_INVALID_PARAM.

Philip — Fri, 19 Oct 2018 14:32:14 GMT

Hi Martin.

So, I made a copy of the original multilink_central example from the SDK, and made all the NUS changes I did first time around to it again as a fresh project and it now works!? I did a diff on the two main files and they are the same, so are the configs. Not sure what is going on but must be a weird issue with the first project.

The m_gatt structure variables are now set and don't start changing all the time.

I think a good thing to take from this is that rebuilding the project may help solve some weird issues like this one.

Thanks for your help Martin, ended up pointing me in the right direction.

Phil

RE: nRF52840 - sd_ble_gattc_exchange_mtu_request() returned NRF_ERROR_INVALID_PARAM.

Philip — Fri, 19 Oct 2018 09:45:36 GMT

I get the same on my central. However if I let it run after the breakpoint (while peripheral switched off i.e. not connecting) the values all start jumping around to random numbers.

I am using SEGGER embedded studio.

RE: nRF52840 - sd_ble_gattc_exchange_mtu_request() returned NRF_ERROR_INVALID_PARAM.

MartinBL — Fri, 19 Oct 2018 07:25:42 GMT

It may look like your att_mtu_desired variables are not initialized properly, but just contain some random value. Can you try to debug and keep an eye on your m_gatt variable? In the picture below I put a break point below gatt_init() and I can see that my att_mtu_desired variables all hold the value 247.

What compiler are you using? It is strange, because your desired MTUs should all be set when you call nrf_ble_gatt_init().

RE: nRF52840 - sd_ble_gattc_exchange_mtu_request() returned NRF_ERROR_INVALID_PARAM.

Philip — Thu, 18 Oct 2018 20:15:44 GMT

I think my problem is definately something to do with this before the NRF_ERROR_INVALID_PARAM.

<debug> nrf_ble_gatt: Updating ATT MTU to 247 bytes (desired: 4352) on connection 0x0.

Have no idea where the 4352 is coming from.

RE: nRF52840 - sd_ble_gattc_exchange_mtu_request() returned NRF_ERROR_INVALID_PARAM.

Philip — Thu, 18 Oct 2018 19:15:51 GMT

Hi, so it connects and stays connected ok for you?

1 - Same code

2 - nRF5_SDK_15.0.0_a53641a on both applications

3 - Central is nRF52840 dev board, peripheral is nRF52832 dev board.

4 - SD on the nRF52832 is S132, SD on the nRF52840 is S140.

I don't have an extra dev kit to act as a sniffer. We could buy another I suppose.

RE: nRF52840 - sd_ble_gattc_exchange_mtu_request() returned NRF_ERROR_INVALID_PARAM.

MartinBL — Thu, 18 Oct 2018 08:59:03 GMT

Disconnect reason 0x13 (BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION) indicates that the device in the other end of the link (your peripheral) decided to disconnect. It could very well be because of the failed MTU update procedure.

But I'm still not able to recreate the problem.

Are you still using the same code as you have shown here, both on the peripheral and the central?
Are you using SDK 15.0.0 on both applications?
Are both devices nRF52840s?
Are you using S140 v6.0.0 on both applications?

Can you provide a sniffer log? If you have an extra Nordic dev kit to spare you can use our nRF Bluetooth Sniffer solution.

RE: nRF52840 - sd_ble_gattc_exchange_mtu_request() returned NRF_ERROR_INVALID_PARAM.

Philip — Wed, 17 Oct 2018 16:10:45 GMT

Hi. I have just added the answer in this other question (link below), which has solved one issue of it crashing. Now the remaining issue seems to be that the MTU exchange fails, so the link disconnects after about 20 seconds.

<info> app: NUS central link 0x0 disconnected (reason: 0x13)

Here is the log.

devzone.nordicsemi.com/.../multiple-connect-discover-service-multiple-why

RE: nRF52840 - sd_ble_gattc_exchange_mtu_request() returned NRF_ERROR_INVALID_PARAM.

Philip — Wed, 17 Oct 2018 12:41:46 GMT

Hi, I have changed the debug level and get this;

<info> app: Multilink example started.
<info> app: Start scanning for device name SWTG1.
<info> app: Name is a match
<error> nrf_ble_gatt: sd_ble_gattc_exchange_mtu_request() returned NRF_ERROR_INVALID_PARAM.
<info> app: Connection 0x0 established, starting DB discovery.
<debug> ble_db_disc: Starting discovery of service with UUID 0x1 on connection handle 0x0.
<info> app: Start scanning for device name SWTG1.
<debug> nrf_ble_gatt: Peer on connection 0x0 requested an ATT MTU of 247 bytes.
<debug> nrf_ble_gatt: Updating ATT MTU to 247 bytes (desired: 4352) on connection 0x0.
<error> nrf_ble_gatt: sd_ble_gatts_exchange_mtu_reply() returned NRF_ERROR_INVALID_PARAM.
<debug> nrf_ble_gatt: Peer on connection 0x0 requested a data length of 251 bytes.
<debug> nrf_ble_gatt: Updating data length to 182 on connection 0x0.
<debug> nrf_ble_gatt: Data length updated to 182 on connection 0x0.
<debug> nrf_ble_gatt: max_rx_octets: 182
<debug> nrf_ble_gatt: max_tx_octets: 182
<debug> nrf_ble_gatt: max_rx_time: 2120
<debug> nrf_ble_gatt: max_tx_time: 2120
<error> nrf_ble_gatt: sd_ble_gattc_exchange_mtu_request() returned NRF_ERROR_INVALID_PARAM.
<debug> ble_db_disc: Found service UUID 0x1.
<debug> ble_db_disc: Found service UUID 0x0.
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<debug> ble_db_disc: Found service UUID 0x0.
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<debug> ble_db_disc: Found service UUID 0x0.
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<debug> ble_db_disc: Found service UUID 0x0.
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<debug> ble_db_disc: Found service UUID 0x0.
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<debug> ble_db_disc: Found service UUID 0x0.
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<debug> ble_db_disc: Found service UUID 0x0.
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<error> nrf_ble_gatt: sd_ble_gattc_exchange_mtu_request() returned NRF_ERROR_INVALID_PARAM.
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<error> nrf_ble_gatt: sd_ble_gattc_exchange_mtu_request() returned NRF_ERROR_INVALID_PARAM.
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<error> nrf_ble_gatt: sd_ble_gattc_exchange_mtu_request() returned NRF_ERROR_INVALID_PARAM.
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<error> nrf_ble_gatt: sd_ble_gattc_exchange_mtu_request() returned NRF_ERROR_INVALID_PARAM.
<debug> ble_db_disc: Discovery of service with UUID 0x1 completed with success on connection handle 0x0.
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<info> app: NUS service discovered on conn_handle 0x0
<info> app: Connected to device with Nordic UART Service.
<debug> ble_db_disc: Discovery of service with UUID 0x1 completed with success on connection handle 0x0.
<debug> app: call to ble_nus_on_db_disc_evt for instance 0 and link 0x0!
<info> app: NUS service discovered on conn_handle 0x0
<error> app: ERROR 17 [NRF_ERROR_BUSY] at C:\Nordic_Semi\nRF5_SDK_15.0.0_a53641a\examples\ble_central\ble_app_multilink_central - Dock\main.c:215
PC at: 0x0002D77D
<error> app: End of error report

RE: nRF52840 - sd_ble_gattc_exchange_mtu_request() returned NRF_ERROR_INVALID_PARAM.

MartinBL — Wed, 17 Oct 2018 12:29:13 GMT

I still don't get the same output as you. Can you try to set log default level to 'debug'?

After I did that I get this output:

RE: nRF52840 - sd_ble_gattc_exchange_mtu_request() returned NRF_ERROR_INVALID_PARAM.

Philip — Tue, 16 Oct 2018 12:55:30 GMT

Hi Martin, here are the files. Same a before, apart from maybe a few logging bits.

I have also attached the peripheral main.c, because I added some manufacturer data, don't think that will have an impact.

Thanks

devzone.nordicsemi.com/.../multilink_5F00_central_5F00_nus.zip devzone.nordicsemi.com/.../2867.uart_5F00_peripheral.zip

RE: nRF52840 - sd_ble_gattc_exchange_mtu_request() returned NRF_ERROR_INVALID_PARAM.

MartinBL — Tue, 16 Oct 2018 12:47:15 GMT

Hi,

How can I reproduce this? I tested your code, but just I got this output:

Can you upload your most recent code?

RE: nRF52840 - sd_ble_gattc_exchange_mtu_request() returned NRF_ERROR_INVALID_PARAM.

Philip — Mon, 15 Oct 2018 13:58:52 GMT

Have added some logging and in nrf_ble_gatt.c the code below is trying to set the desired mtu to 4352 bytes?

NRF_LOG_INFO("MTU to %u bytes", p_gatt->links[conn_handle].att_mtu_desired);

err_code = sd_ble_gattc_exchange_mtu_request(conn_handle,
p_gatt->links[conn_handle].att_mtu_desired);

RE: nRF52840 - sd_ble_gattc_exchange_mtu_request() returned NRF_ERROR_INVALID_PARAM.

Philip — Mon, 15 Oct 2018 11:41:13 GMT

EDIT- Forgot this method gatt_evt_handler, and edited void gatt_init(void). Still the same error tho.

/**@brief Function for handling events from the GATT library. */
void gatt_evt_handler(nrf_ble_gatt_t * p_gatt, nrf_ble_gatt_evt_t const * p_evt)
{
    if (p_evt->evt_id == NRF_BLE_GATT_EVT_ATT_MTU_UPDATED)
    {
        NRF_LOG_INFO("ATT MTU exchange completed.");

        m_ble_nus_max_data_len = p_evt->params.att_mtu_effective - OPCODE_LENGTH - HANDLE_LENGTH;
        NRF_LOG_INFO("Ble NUS max data length set to 0x%X(%d)", m_ble_nus_max_data_len, m_ble_nus_max_data_len);
    }
}

/**@brief Function for initializing the GATT library. */
void gatt_init(void)
{
    ret_code_t err_code;

    err_code = nrf_ble_gatt_init(&m_gatt, gatt_evt_handler);
    APP_ERROR_CHECK(err_code);

    err_code = nrf_ble_gatt_att_mtu_central_set(&m_gatt, NRF_SDH_BLE_GATT_MAX_MTU_SIZE);
    APP_ERROR_CHECK(err_code);
}