Can't connect to fsc-bt986

[mingchi21]

Board

XIAO-ESP32C3

Device Description

Bare XIAO-ESP32C3 board

Hardware Configuration

None

Version

v3.3.2

Type

Question

IDE Name

Arduino 2.0

Operating System

Windows 10

Flash frequency

160 Mhz

PSRAM enabled

yes

Upload speed

921600

Description

I hava a thermal printer with fsc-bt986 module, which is tested that is workable with Android.
And I am trying to connect to the thermal printer by ESP32, but get error response.

Sketch

pClient  = BLEDevice::createClient();
String mac_addr = String(szMacAddress);
pClient->connect(*Server_BLE_Address);
if (!pClient->isConnected())
    {
      Serial.println("Connect failed");
      return false;
    }

Debug Message

- Created client, connecting to dc:0d:30:73:95:59
[ 50524][D][BLEClient.cpp:944] handleGAPEvent(): BLEClient
[ 50524][I][BLEClient.cpp:983] handleGAPEvent(): BLEClient
[ 50524][I][BLEDevice.cpp:683] removePeerDevice(): remove: 0, GATT role client
[ 50525][D][BLESecurity.cpp:192] resetSecurity(): resetSecurity: Resetting security state
[ 50525][D][BLEClient.cpp:406] onDisconnect(): BLEClientCallbacks
[ 80522][D][BLEClient.cpp:944] handleGAPEvent(): BLEClient
[ 80523][D][BLEUtils.cpp:2190] gapEventToString(): gapEventToString: Unknown event type 38 0x26
[ 80523][D][BLEClient.cpp:944] handleGAPEvent(): BLEClient
[ 80523][E][BLEClient.cpp:854] connect(): Connection failed; status=13 Operation timed out.

Other Steps to Reproduce

No response

I have checked existing issues, online documentation and the Troubleshooting Guide

• I confirm I have checked existing issues, online documentation and Troubleshooting guide.

[lucasssvaz]

Are you using some library to connect to it ? Could you please provide a minimal sketch to reproduce this issue ?

[mingchi21]

I just figure out how to connect to fsc-bt986.
I try to connect fsc-bt986 by MAC address, but failed

BLEAddress *Server_BLE_Address;

bool connect_ble(const char *szMacAddress)
{
  pClient  = BLEDevice::createClient();
  String mac_addr = String(szMacAddress);
  Server_BLE_Address = new BLEAddress(mac_addr);
  pClient->connect(*Server_BLE_Address); // this is fail
  if (!pClient->isConnected())
    {
      Serial.println("Connect failed");
      return false;
    }
   return true;
}

And try to connect by BLEAdvertisedDevice, this will work

char targetMacAddr[20];
static BLEAdvertisedDevice *myDevice;
/**
 * Scan for BLE servers and find the first one that advertises the service we are looking for.
 */
class MyAdvertisedDeviceCallbacks : public BLEAdvertisedDeviceCallbacks {
  /**
   * Called for each advertising BLE server.
   */
  void onResult(BLEAdvertisedDevice advertisedDevice) {
    Serial.print("BLE Advertised Device found: ");
    Serial.println(advertisedDevice.toString().c_str());

    if(!strncmp(advertisedDevice.getAddress().toString().c_str(), targetMacAddr, 18))
    {
      Serial.println("Found device, Stop ble scan");
      BLEDevice::getScan()->stop();
      myDevice = new BLEAdvertisedDevice(advertisedDevice);
    }  // Found our target
  }  // onResult
};  // MyAdvertisedDeviceCallbacks

bool connect_ble(const char *szMacAddress)
{
  pClient  = BLEDevice::createClient();
  strncpy(targetMacAddr, szMacAddress, 18);
  targetMacAddr[18] = 0;
  if(myDevice != NULL)
  {
    delete myDevice;
  }
  myDevice = NULL;
  BLEScan *pBLEScan = BLEDevice::getScan();
  pBLEScan->setAdvertisedDeviceCallbacks(new MyAdvertisedDeviceCallbacks());
  pBLEScan->setInterval(1349);
  pBLEScan->setWindow(449);
  pBLEScan->setActiveScan(true);
  pBLEScan->start(5, false);
  timeout = 5;
  while(myDevice == NULL){
    delay(1000);
    if(--timeout == 0){
        return false;
    }
  }
  pClient->connect(myDevice); // This is OK
  if (!pClient->isConnected())
    {
      Serial.println("Connect failed");
      return false;
    }
    return true;
}

Conclusion:
For fsc-bt986 module:
pClient->connect(BLEAddress); // this is fail
pClient->connect(BLEAdvertisedDevice); // this is OK