Swift Pairing for custom gatt service

[bscdb]

Hi,

I am using custom gatt service & I have included some of the code which supports swift pairing from ble_hid_mouse example. Here is my sniffer log -

mtu_log.pcapng

& the jlink rtt log -

paired - Copy.txt

For my application, the MTU size is 32 & data length is 36.

Windows keeps negotiating the size to be 512.

After I pair to the peripheral by connecting through the Windows bluetooth menu, it takes 1 minute to establish the ble connection & start data communication. If I dont pair, then the connection is quick. Now I know you will tell me the app has to make a connection. But I would also like to support manual pairing. Our device gets bricked if someone accidentally pairs with the device through Windows bluetooth menu. To avoid this I had to add the swift pairing support.

How do I expedite the connection on Windows for swift pairing? (note the same firmware without swift pairing feature works on Android OS perfectly fine with or without pairing.)

[bscdb]

I'm using SDK 16.0. I had tried the above solution by referring to https://devzone.nordicsemi.com/f/nordic-q-a/50982/disconnect-after-a-while-using-nrf52840-sdk-v15-2-0-s140-v6-1-1-and-nokia-5-phone, but the behavior is still the same.

If it helps, I captured logs again after adding the above 4 lines to the code.

new_rtt_log.txt

new_log.pcapng

You already have the previous log files.

[Simonr]

Hi Sonal

You added the lines suggested in your ble_evt_handler function, correct? 

The disconnect reason is still the same (0x2A) and is defined by the spec. as: "The Different Transaction Collision error code indicates that an LMP transaction or LL Procedure was started that collides with an ongoing transaction". 

Please also try calling sd_ble_opt_set(BLE_GAP_OPT_AUTH_PAYLOAD_TIMEOUT, &opt); to trigger a LL_PING_REQ from the peripheral side.

Best regards,

Simon

[bscdb]

Yes Simonr, I added all the above 4 lines & I attached the corresponding logs in my previous reply.

case BLE_GAP_EVT_CONNECTED:
			NRF_LOG_DEBUG("Connected.");
            m_conn_handle = p_ble_evt->evt.gap_evt.conn_handle;
            err_code = nrf_ble_qwr_conn_handle_assign(&m_qwr, m_conn_handle);
            APP_ERROR_CHECK(err_code);
			
			opt.gap_opt.auth_payload_timeout.conn_handle = m_conn_handle;
			opt.gap_opt.auth_payload_timeout.auth_payload_timeout = 3000;
			err_code = sd_ble_opt_set(BLE_GAP_OPT_AUTH_PAYLOAD_TIMEOUT, &opt);
			APP_ERROR_CHECK(err_code);		
		
			connection_tx_power_set();	/* +4dB Radio Setting */
			/*SET CONN PIN HIGH AFTER BLUETOOTH CONNECTION*/
			nrf_gpio_pin_set(0);  
			/*AFTER BLUETOOTH CONNECTION, SET THE FLAG HIGH*/
			ble_connected = true;
			NRF_LOG_DEBUG("Connected to %x:%x:%x:%x:%x:%x\r\n", p_ble_evt->evt.gap_evt.params.connected.peer_addr.addr[0]);
			/*Testing*/
			// only trigger event if more than 3 rssi samples have deviated from the last reported rssi by 10db or more
     		// sd_ble_gap_rssi_start(uint16_t conn_handle, uint8_t threshold_dbm, uint8_t skip_count))
			sd_ble_gap_rssi_start(m_conn_handle, 10, 3);	/*rssi*/ //Print RSSI every time it changes with more than 10dB
            break;

But that did not solve the issue.

[Simonr]

Hi

Can you try adding a small delay in nrf_ble_gatt.c as shown below? This is supposed to avoid an LMP_RESPONSE_TIMEOUT, which your issue might be a variant of.

static void on_connected_evt(nrf_ble_gatt_t * p_gatt, ble_evt_t const * p_ble_evt)

{

…

        nrf_delay_ms(100); // #include "nrf_delay.h"

        err_code = sd_ble_gattc_exchange_mtu_request(conn_handle, p_link->att_mtu_desired);

…

}

Best regards,

Simon

[bscdb]

Now it takes more than a minute to connect.  Behavior is still the same..

Here are the logs - 

1. Added delay along with the above 4 lines

with_delay_and_4_lines.pcapng

RTT_with_delay_and_4_lines.txt

2. Added delay only

with_delay.pcapng

RTT_with_delay.txt

In both cases, the peripheral connects to Windows OS but it takes more than a minute.

I also tried increasing/decreasing the time in these 2 lines, but no luck

opt.gap_opt.auth_payload_timeout.auth_payload_timeout = 3000;

nrf_delay_ms(100);