Why is the service channel for the Bluetooth SPP connection client function hardcoded to 0xff?

Troubleshooting
1

void bt_spp_client_start_w4conn(BTS2S_BD_ADDR *bd_addr, U8 *uuid, U8 uuid_len)
{
spp_clt_conn_req_ext(bd_addr,
0xff,
FALSE,
NULL,
uuid,
uuid_len);
USER_TRACE(“>> SPP init connect device: %04X:%02X:%06lX\n”,
bd_addr->nap,
bd_addr->uap,
bd_addr->lap);
}

The normal procedure should be to first use SDP to discover the service channel, and then pass the channel number into this function, right?

2

[210399] I/btapp_spps: >> SPP connect device address: 7400:49:FFFFFF

[210461] D/bt_common: [spp_debug] add new connect: 7400:49:FFFFFF
[210516] D/bt_common: svc_set srch_req_hdl 665
[210557] D/bt_cm: fsm: SDC st:0 evt:3
[210591] D/bt_cm: fsm: L2C_CH st:0 evt:0
[210626] D/bt_cm: fsm: L2C_CH st:1 evt:5
[210662] D/bt_cm: fsm: L2C_CID st:0 evt:0
[210699] D/bt_common: ACL connection request with BD: ffffff:49:7400

[210760] D/bt_common: hcicm_send_hci_conn_req

[210824] I/bt_cm: DM_ACL_CREATE_CONN_STATUS
[210862] D/NO_TAG: Unknown message class: 2

Also, in the log line “[210699] D/bt_common: ACL connection request with BD: ffffff:49:7400”, is the Bluetooth address incorrectly formatted with LAP and NAP reversed?

3

image You need to call this interface first to perform an SDP query, and then call the connection interface.

4 
        else if (strcmp(argv[1], "send_data") == 0)
        {
            bd_addr_t mac;
            bt_addr_convert_from_string_to_general(argv[2], &mac);
            uint8_t srv_chl = atoi(argv[3]);
            char *test_str = "This is spp test!!!";
            U8 len = (U8)bstrlen(test_str);
            U8 *data = (U8 *)bmalloc(len);
            bmemcpy(data, test_str, len);

            bt_interface_spp_send_data_ext(data, len, (bt_notify_device_mac_t *)&mac, srv_chl);
        }

This is a code snippet from an SPP example. Here, memory is allocated for data, but I don’t see any explicit memory release. Is the memory freed inside the SPP API?

5

Yes, this memory will be released at the underlying level.