Add BluetoothSerial library (#1144)

* Add BluetoothSerial library

A simple UART to Classical Bluetooth bridge for ESP32

* Create README.md

* Fix typos

* Replace deprecated header and small fixes

* Add coexistence with BLE

* Add missing semicolon

libraries/BluetoothSerial/README.md

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+### Bluetooth Serial Library
+
+A simple Serial compatible library using ESP32 classical bluetooth (SPP)
+
+
+
+#### How to use it?
+
+- Download one bluetooth terminal app in your smartphone<br>
+For Android: https://play.google.com/store/apps/details?id=de.kai_morich.serial_bluetooth_terminal <br>
+For iOS: https://itunes.apple.com/us/app/hm10-bluetooth-serial-lite/id1030454675
+
+- Flash an example sketch to your ESP32
+
+- Scan and pair the device in your smartphone
+
+- Open the bluetooth terminal app
+
+- Enjoy

libraries/BluetoothSerial/examples/SerialToSerialBT/SerialToSerialBT.ino

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+//This example code is in the Public Domain (or CC0 licensed, at your option.)
+//By Evandro Copercini - 2018
+//
+//This example creates a bridge between Serial and Classical Bluetooth (SPP)
+//and also demonstrate that SerialBT have the same functionalities of a normal Serial
+
+#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
+  Serial.println("The device started, now you can pair it with bluetooth!");
+}
+
+void loop() {
+  if (Serial.available()) {
+    SerialBT.write(Serial.read());
+  }
+  if (SerialBT.available()) {
+    Serial.write(SerialBT.read());
+  }
+  delay(20);
+}

libraries/BluetoothSerial/keywords.txt

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+#######################################
+# Syntax Coloring Map For BluetoothSerial
+#######################################
+
+#######################################
+# Library (KEYWORD3)
+#######################################
+
+BluetoothSerial	KEYWORD3
+
+#######################################
+# Datatypes (KEYWORD1)
+#######################################
+
+BluetoothSerial	KEYWORD1
+
+#######################################
+# Methods and Functions (KEYWORD2)
+#######################################
+
+SerialBT	KEYWORD2
+
+
+#######################################
+# Constants (LITERAL1)
+#######################################

libraries/BluetoothSerial/library.properties

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+name=BluetoothSerial
+version=1.0
+author=Evandro Copercini
+maintainer=Evandro Copercini
+sentence=Simple UART to Classical Bluetooth bridge for ESP32
+paragraph=
+category=Communication
+url=
+architectures=esp32

libraries/BluetoothSerial/src/BluetoothSerial.cpp

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+// Copyright 2018 Evandro Luis Copercini
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "sdkconfig.h"
+
+#if defined(CONFIG_BT_ENABLED) && defined(CONFIG_BLUEDROID_ENABLED)
+
+#ifdef ARDUINO_ARCH_ESP32
+#include "esp32-hal-log.h"
+#endif
+
+#include "BluetoothSerial.h"
+
+#include "esp_bt.h"
+#include "esp_bt_main.h"
+#include "esp_gap_bt_api.h"
+#include "esp_bt_device.h"
+#include "esp_spp_api.h"
+
+#define SPP_SERVER_NAME "ESP32_SPP_SERVER"
+
+#define QUEUE_SIZE 256
+uint32_t client;
+xQueueHandle SerialQueueBT;
+
+static const esp_spp_mode_t esp_spp_mode = ESP_SPP_MODE_CB;
+static const esp_spp_sec_t sec_mask = ESP_SPP_SEC_NONE;
+static const esp_spp_role_t role_slave = ESP_SPP_ROLE_SLAVE;
+
+static void esp_spp_cb(esp_spp_cb_event_t event, esp_spp_cb_param_t *param)
+{
+    switch (event)
+    {
+    case ESP_SPP_INIT_EVT:
+        ESP_LOGI(SPP_TAG, "ESP_SPP_INIT_EVT");
+        esp_bt_gap_set_scan_mode(ESP_BT_SCAN_MODE_CONNECTABLE_DISCOVERABLE);
+        esp_spp_start_srv(sec_mask, role_slave, 0, SPP_SERVER_NAME);
+        break;
+    case ESP_SPP_DISCOVERY_COMP_EVT:
+        ESP_LOGI(SPP_TAG, "ESP_SPP_DISCOVERY_COMP_EVT");
+        break;
+    case ESP_SPP_OPEN_EVT:
+        ESP_LOGI(SPP_TAG, "ESP_SPP_OPEN_EVT");
+        break;
+    case ESP_SPP_CLOSE_EVT:
+        client = 0;
+        ESP_LOGI(SPP_TAG, "ESP_SPP_CLOSE_EVT");
+        break;
+    case ESP_SPP_START_EVT:
+        ESP_LOGI(SPP_TAG, "ESP_SPP_START_EVT");
+        break;
+    case ESP_SPP_CL_INIT_EVT:
+        ESP_LOGI(SPP_TAG, "ESP_SPP_CL_INIT_EVT");
+        break;
+    case ESP_SPP_DATA_IND_EVT:
+        ESP_LOGV(SPP_TAG, "ESP_SPP_DATA_IND_EVT len=%d handle=%d", param->data_ind.len, param->data_ind.handle);
+        //esp_log_buffer_hex("",param->data_ind.data,param->data_ind.len); //for low level debug
+
+        if (SerialQueueBT != 0){
+            for (int i = 0; i < param->data_ind.len; i++)
+                xQueueSend(SerialQueueBT, param->data_ind.data + i, (TickType_t)0);
+        }
+        else {
+            ESP_LOGE(SPP_TAG, "SerialQueueBT ERROR");
+        }
+        break;
+    case ESP_SPP_CONG_EVT:
+        ESP_LOGI(SPP_TAG, "ESP_SPP_CONG_EVT");
+        break;
+    case ESP_SPP_WRITE_EVT:
+        ESP_LOGV(SPP_TAG, "ESP_SPP_WRITE_EVT");
+        break;
+    case ESP_SPP_SRV_OPEN_EVT:
+        client = param->open.handle;
+        ESP_LOGI(SPP_TAG, "ESP_SPP_SRV_OPEN_EVT");
+        break;
+    default:
+        break;
+    }
+}
+
+static bool _init_bt(const char *deviceName)
+{
+    if (!btStarted() && !btStart()){
+        ESP_LOGE(SPP_TAG, "%s initialize controller failed\n", __func__);
+        return false;
+    }
+    
+    esp_bluedroid_status_t bt_state = esp_bluedroid_get_status();
+    if (bt_state == ESP_BLUEDROID_STATUS_UNINITIALIZED){
+        if (esp_bluedroid_init()) {
+            ESP_LOGE(SPP_TAG, "%s initialize bluedroid failed\n", __func__);
+            return false;
+        }
+    }
+    
+    if (bt_state != ESP_BLUEDROID_STATUS_ENABLED){
+        if (esp_bluedroid_enable()) {
+            ESP_LOGE(SPP_TAG, "%s enable bluedroid failed\n", __func__);
+            return false;
+        }
+    }
+
+    if (esp_spp_register_callback(esp_spp_cb) != ESP_OK){
+        ESP_LOGE(SPP_TAG, "%s spp register failed\n", __func__);
+        return false;
+    }
+
+    if (esp_spp_init(esp_spp_mode) != ESP_OK){
+        ESP_LOGE(SPP_TAG, "%s spp init failed\n", __func__);
+        return false;
+    }
+
+    SerialQueueBT = xQueueCreate(QUEUE_SIZE, sizeof(uint8_t)); //initialize the queue
+    if (SerialQueueBT == NULL){
+        ESP_LOGE(SPP_TAG, "%s Queue creation error\n", __func__);
+        return false;
+    }
+    esp_bt_dev_set_device_name(deviceName);
+
+    return true;
+}
+
+static bool _stop_bt()
+{
+    if (btStarted()){
+        esp_bluedroid_disable();
+        esp_bluedroid_deinit();
+        btStop();
+    }
+    return true;
+}
+
+/*
+ * Serial Bluetooth Arduino
+ *
+ * */
+
+BluetoothSerial::BluetoothSerial()
+{
+    local_name = "ESP32"; //default bluetooth name
+}
+
+BluetoothSerial::~BluetoothSerial(void)
+{
+    _stop_bt();
+}
+
+bool BluetoothSerial::begin(String localName)
+{
+    if (localName.length()){
+        local_name = localName;
+    }
+    return _init_bt(local_name.c_str());
+}
+
+int BluetoothSerial::available(void)
+{
+    if (!client || SerialQueueBT == NULL){
+        return 0;
+    }
+    return uxQueueMessagesWaiting(SerialQueueBT);
+}
+
+int BluetoothSerial::peek(void)
+{
+    if (available()){
+        if (!client || SerialQueueBT == NULL){
+            return 0;
+        }
+
+        uint8_t c;
+        if (xQueuePeek(SerialQueueBT, &c, 0)){
+            return c;
+        }
+    }
+    return -1;
+}
+
+int BluetoothSerial::read(void)
+{
+    if (available()){
+        if (!client || SerialQueueBT == NULL){
+            return 0;
+        }
+
+        uint8_t c;
+        if (xQueueReceive(SerialQueueBT, &c, 0)){
+            return c;
+        }
+        return 0;
+    }
+}
+
+size_t BluetoothSerial::write(uint8_t c)
+{
+    if (client){
+        uint8_t buffer[1];
+        buffer[0] = c;
+        esp_spp_write(client, 1, buffer);
+        return 1;
+    }
+    return -1;
+}
+
+size_t BluetoothSerial::write(const uint8_t *buffer, size_t size)
+{
+    if (client){
+        esp_spp_write(client, size, (uint8_t *)buffer);
+    }
+    return size;
+}
+
+void BluetoothSerial::flush()
+{
+    if (client){
+        int qsize = available();
+        uint8_t buffer[qsize];
+        esp_spp_write(client, qsize, buffer);
+    }
+}
+
+void BluetoothSerial::end()
+{
+    _stop_bt();
+}
+
+#endif

libraries/BluetoothSerial/src/BluetoothSerial.h

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+// Copyright 2018 Evandro Luis Copercini
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef _BLUETOOTH_SERIAL_H_
+#define _BLUETOOTH_SERIAL_H_
+
+#include "sdkconfig.h"
+
+#if defined(CONFIG_BT_ENABLED) && defined(CONFIG_BLUEDROID_ENABLED)
+
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "esp_bt.h"
+
+#include "Arduino.h"
+#include "Stream.h"
+
+class BluetoothSerial: public Stream
+{
+    public:
+
+        BluetoothSerial(void);
+        ~BluetoothSerial(void);
+
+        bool begin(String localName=String());
+        int available(void);
+        int peek(void);
+        int read(void);
+        size_t write(uint8_t c);
+        size_t write(const uint8_t *buffer, size_t size);
+        void flush();
+        void end(void);
+
+    private:
+        String local_name;
+
+};
+
+#endif
+
+#endif