feature(BluetoothSerial): add pinCode function

Author: xiongyumail

Diff for: libraries/BluetoothSerial/examples/SerialToSerialBT/SerialToSerialBT.ino

@@ -6,15 +6,12 @@
 
 #include "BluetoothSerial.h"
 
-#if !defined(CONFIG_BT_ENABLED) || !defined(CONFIG_BLUEDROID_ENABLED)
-#error Bluetooth is not enabled! Please run `make menuconfig` to and enable it
-#endif
-
 BluetoothSerial SerialBT;
 
 void setup() {
   Serial.begin(115200);
   SerialBT.begin("ESP32test"); //Bluetooth device name
+  SerialBT.pinCode("3456");
   Serial.println("The device started, now you can pair it with bluetooth!");
 }
 

Diff for: libraries/BluetoothSerial/src/BluetoothSerial.cpp

@@ -384,6 +384,22 @@ bool BluetoothSerial::begin(String localName)
     return _init_bt(local_name.c_str());
 }
 
+bool BluetoothSerial::pinCode( char* pswd)
+{
+    if(strlen(pswd)==4){
+        esp_bt_pin_type_t pin_type = ESP_BT_PIN_TYPE_FIXED;
+        esp_bt_pin_code_t pin_code;
+        pin_code[0] = pswd[0];
+        pin_code[1] = pswd[1] ;
+        pin_code[2] = pswd[2];
+        pin_code[3] = pswd[3];
+        esp_bt_gap_set_pin(pin_type, 4, pin_code);
+        return true;
+    }
+    else
+        return false;
+}
+
 int BluetoothSerial::available(void)
 {
     if (_spp_rx_queue == NULL){

Diff for: libraries/BluetoothSerial/src/BluetoothSerial.h

@@ -22,6 +22,11 @@
 #include "Arduino.h"
 #include "Stream.h"
 #include <esp_spp_api.h>
+#include "esp_gap_bt_api.h"   
+
+#if !defined(CONFIG_BT_ENABLED) || !defined(CONFIG_BLUEDROID_ENABLED)
+#error Bluetooth is not enabled! Please run `make menuconfig` to and enable it
+#endif
 
 class BluetoothSerial: public Stream
 {
@@ -31,6 +36,7 @@ class BluetoothSerial: public Stream
         ~BluetoothSerial(void);
 
         bool begin(String localName=String());
+        bool pinCode(char* pswd);
         int available(void);
         int peek(void);
         bool hasClient(void);