Support for Master mode, Pin and SSP (#3219)

* 20190916 - initial: support for Master mode, Pin and SSP

* 20190916 - initial: Add example app for Master mode

* 20190916 - initial: Force another build

* 20190916 - connect would use resolved address as preference and remove now redundant _remote_address

* 20190916 - rework set/reset/default pin logic

* 20190916 - cleanup: remove static vars, add/use constants, fix typos

* 20190916 - fix build issues and implement geoup events for status verification.

* 20190916 - remove extra lines,misc

* 20190916 - rework ESP_BT_GAP_DISC_RES_EVT, added SPP_DISCONNECTED bit for disconnect event. + timeout for disconnect()

* 20190916 - Small log change to improve log sequencing

* 20190916 - remove static from local vars

* 20190916 - Limited scope and duration for the scan, log device address during scan in info mode as it is very difficult to find out sometimes. Fixed get_name_from_eir() not resetting the name when called.

* 20190916 - break property for loop during scan when name matches.

* 20190916 - misc

* 20190916 - SPP_DISCONNECT state updates

* 20190916 - formatting, remove some strange syntax from initiator code

* 20190916 - Add comments to the example about connect(...) usage and timeouts

* 20190916 - fix disconnect() without timeout

* 20190916 - Add example comment to view BT address and name during connect(name)

* 20190916 - wording in example comments

* 20190916 - rework connect() and disconnect() methods to help with concurrency and more authoritative status returned back to caller. Automatic disconnect in connect() methods

* 20190916 - optimize code

* 20190916 - optimize code - more

* 20190916 - add timeout for pin set

* 20190916 - change scan mode to ESP_BT_SCAN_MODE_CONNECTABLE_DISCOVERABLE

* 20190916 - update example code slightly

* 20190916 - increase READY_TIMEOUT to 10 secs

* 20190916 - typo in example and move waitForConnect() to static area

* 20190916 - update example comments

* 20190916 - update example comments

* 20190916 - update example comments

* 20190916 - add new example to remove paired devices from ESP32

* 20190916 - correct typo in example

* 20190916 - update example comment, add remove_bond_device() method for convenience.

* 20190916 - reword example comment.

* 20190916 - rename remove_bond_device()

* 20190916 - rename removePairedDevice() to unpairDevice()

* 20190916 - code review changes

* 20190916 - fix return value in setup() od example

libraries/BluetoothSerial/examples/SerialToSerialBTM/SerialToSerialBTM.ino

@@ -0,0 +1,56 @@
+//This example code is in the Public Domain (or CC0 licensed, at your option.)
+//By Victor Tchistiak - 2019
+//
+//This example demostrates master mode bluetooth connection and pin 
+//it creates a bridge between Serial and Classical Bluetooth (SPP)
+//this is an extention of the SerialToSerialBT example by Evandro Copercini - 2018
+//
+
+#include "BluetoothSerial.h"
+
+BluetoothSerial SerialBT;
+
+String MACadd = "AA:BB:CC:11:22:33";
+uint8_t address[6]  = {0xAA, 0xBB, 0xCC, 0x11, 0x22, 0x33};
+//uint8_t address[6]  = {0x00, 0x1D, 0xA5, 0x02, 0xC3, 0x22};
+String name = "OBDII";
+char *pin = "1234"; //<- standard pin would be provided by default
+bool connected;
+
+void setup() {
+  Serial.begin(115200);
+  //SerialBT.setPin(pin);
+  SerialBT.begin("ESP32test", true); 
+  //SerialBT.setPin(pin);
+  Serial.println("The device started in master mode, make sure remote BT device is on!");
+  
+  // connect(address) is fast (upto 10 secs max), connect(name) is slow (upto 30 secs max) as it needs
+  // to resolve name to address first, but it allows to connect to different devices with the same name.
+  // Set CoreDebugLevel to Info to view devices bluetooth address and device names
+  connected = SerialBT.connect(name);
+  //connected = SerialBT.connect(address);
+  
+  if(connected) {
+    Serial.println("Connected Succesfully!");
+  } else {
+    while(!SerialBT.connected(10000)) {
+      Serial.println("Failed to connect. Make sure remote device is available and in range, then restart app."); 
+    }
+  }
+  // disconnect() may take upto 10 secs max
+  if (SerialBT.disconnect()) {
+    Serial.println("Disconnected Succesfully!");
+  }
+  // this would reconnect to the name(will use address, if resolved) or address used with connect(name/address).
+  SerialBT.connect();
+}
+
+void loop() {
+  if (Serial.available()) {
+    SerialBT.write(Serial.read());
+  }
+  if (SerialBT.available()) {
+    Serial.write(SerialBT.read());
+  }
+  delay(20);
+}

libraries/BluetoothSerial/examples/bt_remove_paired_devices/bt_remove_paired_devices.ino

@@ -0,0 +1,87 @@
+//This example code is in the Public Domain (or CC0 licensed, at your option.)
+//By Victor Tchistiak - 2019
+//
+//This example demonstrates reading and removing paired devices stored on the ESP32 flash memory
+//Sometimes you may find your ESP32 device could not connect to the remote device despite
+//many successful connections earlier. This is most likely a result of client replacing your paired
+//device info with new one from other device. The BT clients store connection info for paired devices,
+//but it is limited to a few devices only. When new device pairs and number of stored devices is exceeded,
+//one of the previously paired devices would be replaced with new one.
+//The only remedy is to delete this saved bound device from your device flash memory
+//and pair with the other device again.
+//
+#include "esp_bt_main.h"
+#include "esp_bt_device.h"
+#include"esp_gap_bt_api.h"
+#include "esp_err.h"
+
+#define REMOVE_BONDED_DEVICES 0   // <- Set to 0 to view all bonded devices addresses, set to 1 to remove
+
+#define PAIR_MAX_DEVICES 20
+uint8_t pairedDeviceBtAddr[PAIR_MAX_DEVICES][6];
+char bda_str[18];
+
+bool initBluetooth()
+{
+  if(!btStart()) {
+    Serial.println("Failed to initialize controller");
+    return false;
+  }
+ 
+  if(esp_bluedroid_init() != ESP_OK) {
+    Serial.println("Failed to initialize bluedroid");
+    return false;
+  }
+ 
+  if(esp_bluedroid_enable() != ESP_OK) {
+    Serial.println("Failed to enable bluedroid");
+    return false;
+  }
+  return true;
+}
+
+char *bda2str(const uint8_t* bda, char *str, size_t size)
+{
+  if (bda == NULL || str == NULL || size < 18) {
+    return NULL;
+  }
+  sprintf(str, "%02x:%02x:%02x:%02x:%02x:%02x",
+          bda[0], bda[1], bda[2], bda[3], bda[4], bda[5]);
+  return str;
+}
+ 
+void setup() {
+  Serial.begin(115200);
+ 
+  initBluetooth();
+  Serial.print("ESP32 bluetooth address: "); Serial.println(bda2str(esp_bt_dev_get_address(), bda_str, 18));
+  // Get the numbers of bonded/paired devices in the BT module
+  int count = esp_bt_gap_get_bond_device_num();
+  if(!count) {
+    Serial.println("No bonded device found.");
+  } else {
+    Serial.print("Bonded device count: "); Serial.println(count);
+    if(PAIR_MAX_DEVICES < count) {
+      count = PAIR_MAX_DEVICES; 
+      Serial.print("Reset bonded device count: "); Serial.println(count);
+    }
+    esp_err_t tError =  esp_bt_gap_get_bond_device_list(&count, pairedDeviceBtAddr);
+    if(ESP_OK == tError) {
+      for(int i = 0; i < count; i++) {
+        Serial.print("Found bonded device # "); Serial.print(i); Serial.print(" -> ");
+        Serial.println(bda2str(pairedDeviceBtAddr[i], bda_str, 18));     
+        if(REMOVE_BONDED_DEVICES) {
+          esp_err_t tError = esp_bt_gap_remove_bond_device(pairedDeviceBtAddr[i]);
+          if(ESP_OK == tError) {
+            Serial.print("Removed bonded device # "); 
+          } else {
+            Serial.print("Failed to remove bonded device # ");
+          }
+          Serial.println(i);
+        }
+      }        
+    }
+  }
+}
+ 
+void loop() {}