SD GATT procedure failed on Central device.

RE: SD GATT procedure failed on Central device.

Susheel Nuguru — Fri, 07 Jul 2023 14:33:17 GMT

It would help with sniffer logs but the error you see the same thing as mentioned here. Check the solution mentioned there if that helps.

RE: SD GATT procedure failed on Central device.

sne_333 — Fri, 07 Jul 2023 07:22:13 GMT

Hi , Can you please reply? Is there any way to implement reconnect mechanism?

RE: SD GATT procedure failed on Central device.

sne_333 — Wed, 21 Jun 2023 06:41:57 GMT

Hi Susheel,

Unfortunately I won't be able to capture sniffer logs for some reason. I also feel that there is some issue with function "nrf_ble_scan_connect_with_target".

static void nrf_ble_scan_connect_with_target(nrf_ble_scan_t           const * const p_scan_ctx,
                                             ble_gap_evt_adv_report_t const * const p_adv_report)
{
    ret_code_t err_code;
    scan_evt_t scan_evt;

    // For readability.
    ble_gap_addr_t const        * p_addr        = &p_adv_report->peer_addr;
    ble_gap_scan_params_t const * p_scan_params = &p_scan_ctx->scan_params;
    ble_gap_conn_params_t const * p_conn_params = &p_scan_ctx->conn_params;
    uint8_t                       con_cfg_tag   = p_scan_ctx->conn_cfg_tag;

    // Return if the automatic connection is disabled.
    if (!p_scan_ctx->connect_if_match)
    {
        return;
    }

    // Stop scanning.
    nrf_ble_scan_stop(); 

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

    // Establish connection.
    err_code = sd_ble_gap_connect(p_addr,
                                  p_scan_params,
                                  p_conn_params,
                                  con_cfg_tag);

    NRF_LOG_INFO("Connecting");

    scan_evt.scan_evt_id                    = NRF_BLE_SCAN_EVT_CONNECTING_ERROR;
    scan_evt.params.connecting_err.err_code = err_code;

    NRF_LOG_INFO("Connection status: %d", err_code);

    // If an error occurred, send an event to the event handler.
    if ((err_code != NRF_SUCCESS) && (p_scan_ctx->evt_handler != NULL))
    {
        p_scan_ctx->evt_handler(&scan_evt);
    }

}

Here in this function nrf_ble_scan_stop() is called. My doubt is when peripheral-1 is detected, the central goes into this function and nrf_ble_scan_stop() is called and it connects to peripheral-1. Now as nrf_ble_scan_stop is called the central device does not look for the peripheral-2 and does not connect to it. Am I right?

Thanks & Regards,

Snehal

RE: SD GATT procedure failed on Central device.

Susheel Nuguru — Wed, 21 Jun 2023 06:33:25 GMT

[quote user="snehal_2789"]Can we handle this? Can we set some interval somewhere so that connection to peripherals happen one by one?[/quote]

When two devices are connected then the connection events will be multiplexed over time. Also it should not be possible to lose packets in a connection in BLE. So the main question here is that if the central 2 is transmitting the data in the connection2 and the peripheral2 is not able to process it or if the central2 is not able to transmit data at all?

You need to see the sniffer log to get the answer to the above questions.

If the central2 is transmitting data, then there is some issue with the context in which peripheral2 is processing data. Maybe there is a deadlock or peripheral1 data processing is startving peripheral2 data processing?

RE: SD GATT procedure failed on Central device.

sne_333 — Tue, 20 Jun 2023 07:35:45 GMT

Hi Susheel,

Actually I have identified the issue. I have set scan name filter in my central firmware. Name filter includes 2 peripheral devices. Now the problem is when the scanning starts, the central device scans both and tries to connect to both of them at a time. During this process some packets of one of the peripheral device are lost and it doesn't complete full cycle of connection due to this only pne peripheral is connected properly. In the central logs it shows me that both peripherals initiated connection but no packets are received from the peripheral 2. I can see only peripheral 1 packets.

Can we handle this? Can we set some interval somewhere so that connection to peripherals happen one by one?

Thanks & Regards,

Snehal

RE: SD GATT procedure failed on Central device.

Susheel Nuguru — Mon, 12 Jun 2023 06:29:11 GMT

That is not easy to answer without knowing why the other peripheral does not connect. Do you have any error code when the central sends a connect request or is it just a connect request timed out?

Are you sending the connect request from the central on receiving the adv packet or is there different logic on how you send the connect request?

RE: SD GATT procedure failed on Central device.

sne_333 — Fri, 09 Jun 2023 10:26:56 GMT

Hi Susheel,

I have solved the GATT error. But still if there are 2 peripherals sometimes only one gets connected to the central. My configuration for central is as follows:-

#define APP_BLE_OBSERVER_PRIO               3                                       /**< Application's BLE observer priority. You shouldn't need to modify this value. */
#define APP_BLE_CONN_CFG_TAG                1                                       /**< A tag identifying the SoftDevice BLE configuration. */

#define APP_ADV_INTERVAL                    300                                     /**< The advertising interval (in units of 0.625 ms. This value corresponds to 187.5 ms). */
#define APP_ADV_DURATION                    0                                       /**< The advertising duration (180 seconds) in units of 10 milliseconds. */

#define RTC_INTERVAL                        1000                                    /**< RTC interval (ms). */

#define MIN_CONN_INTERVAL                   MSEC_TO_UNITS(200, UNIT_1_25_MS)        /**< Minimum acceptable connection interval (0.4 seconds). */
#define MAX_CONN_INTERVAL                   MSEC_TO_UNITS(300, UNIT_1_25_MS)        /**< Maximum acceptable connection interval (0.65 second). */



#define SLAVE_LATENCY                       4                                       /**< Slave latency. */
#define CONN_SUP_TIMEOUT                    MSEC_TO_UNITS(5000, UNIT_10_MS)         /**< Connection supervisory time-out (4 seconds). */

#define FIRST_CONN_PARAMS_UPDATE_DELAY      5000                                    /**< Time from initiating event (connect or start of notification) to first time sd_ble_gap_conn_param_update is called (5 seconds). */
#define NEXT_CONN_PARAMS_UPDATE_DELAY       30000                                   /**< Time between each call to sd_ble_gap_conn_param_update after the first call (30 seconds). */
#define MAX_CONN_PARAMS_UPDATE_COUNT        3                                       /**< Number of attempts before giving up the connection parameter negotiation. */



#define NRF_BLE_SCAN_SCAN_INTERVAL 160
#define NRF_BLE_SCAN_SCAN_DURATION 0
#define NRF_BLE_SCAN_SCAN_WINDOW 80
#define NRF_BLE_SCAN_MIN_CONNECTION_INTERVAL 7.5
#define NRF_BLE_SCAN_MAX_CONNECTION_INTERVAL 30
#define NRF_BLE_SCAN_SLAVE_LATENCY 0
#define NRF_BLE_SCAN_SUPERVISION_TIMEOUT 4000

Can we modify any config to get a stable connection from all peripherals?

RE: SD GATT procedure failed on Central device.

sne_333 — Thu, 11 May 2023 07:10:36 GMT

Sorry Susheel I dont have sniffer.

RE: SD GATT procedure failed on Central device.

Susheel Nuguru — Thu, 11 May 2023 07:05:10 GMT

Thanks Snehal,

Sniffer logs will help understand the problem better and faster.

RE: SD GATT procedure failed on Central device.

sne_333 — Tue, 09 May 2023 04:07:56 GMT

Hi Hieu,

I have attached the main and central file over here.devzone.nordicsemi.com/.../Gmain.c

devzone.nordicsemi.com/.../2335.central.c

The gatt_error_handler handler is called from 2 functions from the service initialization file.

devzone.nordicsemi.com/.../service1.c

The request_err_code_handle is called in "request_process" & "queue_process" functions from where the error is seen in logs.

Regarding logs I will capture it today and send you.

Thanks & Regards,

Snehal.

RE: SD GATT procedure failed on Central device.

Hieu — Mon, 08 May 2023 20:20:26 GMT

Hi Snehal,

I see, I didn't know the first connection work, and only the second one failed. Does this happen consistently?

I think the issue likely lies at the other part of your code.

I wonder if perhaps your write attempts would always try to write to both peripherals. Meanwhile, right after connection of the second peripheral, there are still setup activities, such as MTU Exchange and Connection Parameters negotiation, and that causes a write attempt to time out.

However, without details, that is just speculation. Of course, full source file would help, but let's look at some key points first before we eventually get there. Could you please provide these pieces of information?

What the nrf_ble_gq** function call, which results in the error, is, and how is it called?
As much details as possible about the timing of those functions in relation to the connected event
Full log

By the way, not relevant to the issue, but the implementation of gatt_evt_handler() that you took from the SDK is flawed because it would log "ATT MTU exchange completed..." even for non-MTU events. Perhaps you could update it after we are done with this issue.

Regards,

Hieu

RE: SD GATT procedure failed on Central device.

sne_333 — Mon, 08 May 2023 10:17:30 GMT

Hi Hieu,

This error happens during connection establishment. My Gatt initialization is as follows:-

void gatt_evt_handler(nrf_ble_gatt_t * p_gatt, nrf_ble_gatt_evt_t const * p_evt)
{
    if ((m_conn_handle == p_evt->conn_handle) && (p_evt->evt_id == NRF_BLE_GATT_EVT_ATT_MTU_UPDATED))
    {        
        sys_set_peripheral_mtu(p_evt->params.att_mtu_effective - OPCODE_LENGTH - HANDLE_LENGTH);

        NRF_LOG_INFO("Data len is set to 0x%X(%d)", sys_get_peripheral_mtu(), sys_get_peripheral_mtu());
        NRF_LOG_PROCESS();
    }
    NRF_LOG_INFO("ATT MTU exchange completed. central 0x%x peripheral 0x%x",
                  p_gatt->att_mtu_desired_central,
                  p_gatt->att_mtu_desired_periph);
    NRF_LOG_PROCESS();
}



/**@brief Function for initializing the GATT module. */
static void gatt_init(void)
{
    ret_code_t 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);
}

After successful connection the sensors send the device status to the central.

Could it be that you initiate the write too early/before the connection is fully established, such as along with the function to connect?

>> But then why does one sensor connect and the other fails?? If writes are performed too early then the central should get disconnected for both I guess.

Also I have a scan filter in central firmware. It scans from the stored list of names to get connected to the devices nearby.

Thanks & Regards,

Snehal

RE: SD GATT procedure failed on Central device.

Hieu — Mon, 08 May 2023 10:06:20 GMT

Hi Snehal,

How are you setting up the GATT Writes on your central?

Does this error happen a while after the connection is established, or during connection establishment?

[quote user=""]00> <error> nrf_ble_gq: SD GATT procedure (2) failed on connection handle 1 with error: 0x0000000D.[/quote]

This line says that a GATT Write procedure timed out. Do you have any idea what write procedure is happening here?

Could it be that you initiate the write too early/before the connection is fully established, such as along with the function to connect?

Hieu