From ba7164f5cd3af330c6398ef9404e351678e06404 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20Grome=C5=A1?= <jgromes@users.noreply.github.com>
Date: Tue, 24 Jul 2018 09:54:07 +0200
Subject: [PATCH] XBee - implemented API packet reception

---
 examples/XBee_Receive/XBee_Receive.ino | 56 ++++++++++++++++++++++
 src/modules/XBee.cpp                   | 66 +++++++++++++++++++++++++-
 src/modules/XBee.h                     |  5 ++
 3 files changed, 125 insertions(+), 2 deletions(-)
 create mode 100644 examples/XBee_Receive/XBee_Receive.ino

diff --git a/examples/XBee_Receive/XBee_Receive.ino b/examples/XBee_Receive/XBee_Receive.ino
new file mode 100644
index 00000000..342cd356
--- /dev/null
+++ b/examples/XBee_Receive/XBee_Receive.ino
@@ -0,0 +1,56 @@
+/*
+   KiteLib XBee API Receive Example
+
+   This example receives packets using XBee API mode.
+   In API mode, many XBee modules can form a mesh network.
+
+   IMPORTANT: Before uploading this example, make sure that the XBee module
+   is running API ROUTER/ENDPOINT firmware!
+*/
+
+// include the library
+#include <KiteLib.h>
+
+// XBee module is in slot A on the shield
+XBee bee = Kite.ModuleA;
+
+void setup() {
+  Serial.begin(9600);
+
+  // initialize XBee module with baudrate 9600
+  Serial.print(F("[XBee] Initializing ... "));
+  int state = bee.begin(9600);
+  if (state == ERR_NONE) {
+    Serial.println(F("success!"));
+  } else {
+    Serial.print(F("failed, code "));
+    Serial.println(state);
+    while (true);
+  }
+
+  // set PAN ID to 0x0123456789ABCDEF
+  Serial.print(F("[XBee] Setting PAN ID ... "));
+  uint8_t panId[] = {0x01, 0x23, 0x45, 0x67,
+                     0x89, 0xAB, 0xCD, 0xEF};
+  state = bee.setPanId(panId);
+  if (state == ERR_NONE) {
+    Serial.println(F("success!"));
+  } else {
+    Serial.print(F("failed, code "));
+    Serial.println(state);
+    while (true);
+  }
+}
+
+void loop() {
+  // check if XBee received some data
+  if (bee.available() > 0) {
+    // print source address
+    Serial.print("[XBee] Packet source:\t");
+    Serial.println(bee.getPacketSource());
+    
+    // print data
+    Serial.print("[XBee] Packet data:\t");
+    Serial.println(bee.getPacketData());
+  }
+}
diff --git a/src/modules/XBee.cpp b/src/modules/XBee.cpp
index 6414873e..82417068 100644
--- a/src/modules/XBee.cpp
+++ b/src/modules/XBee.cpp
@@ -3,9 +3,20 @@
 XBee::XBee(Module* mod) {
   _mod = mod;
   _frameID = 0x01;
+  _frameLength = 0;
+  _frameHeaderProcessed = false;
+  _packetData = new char[0];
 }
 
 int16_t XBee::begin(long speed) {
+  // set Arduino pins
+  pinMode(A4, OUTPUT);
+  pinMode(A5, OUTPUT);
+  pinMode(3, OUTPUT);
+  digitalWrite(A4, LOW);
+  digitalWrite(A5, LOW);
+  digitalWrite(3, HIGH);
+
   // set module properties
   _mod->baudrate = speed;
   _mod->init(USE_UART, INT_NONE);
@@ -52,15 +63,66 @@ int16_t XBee::transmit(uint8_t* dest, uint8_t* destNetwork, const char* payload,
 }
 
 size_t XBee::available() {
+  // check if there are data available in the buffer
+  size_t serialBytes = _mod->ModuleSerial->available();
+  if(serialBytes < 3) {
+    return(0);
+  } 
   
+  uint8_t header[3];
+  if(!_frameHeaderProcessed) {
+    // read frame header
+    for(uint8_t i = 0; i < 3; i++) {
+      header[i] = _mod->ModuleSerial->read();
+    }
+    
+    // check if we received API frame
+    if(header[0] != XBEE_API_START) {
+      return(0);
+    }
+    
+    // get expected frame length
+    _frameLength = ((header[1] << 8) | header[2]) + 1;
+    _frameHeaderProcessed = true;
+  }
+  
+  // check if the header is complete
+  if(serialBytes < _frameLength) {
+    return(0);
+  }
+  
+  uint8_t* frame = new uint8_t[_frameLength];  //24
+  for(size_t i = 0; i < _frameLength; i++) {
+    frame[i] = _mod->ModuleSerial->read();
+  }
+  
+  // save packet source and data
+  size_t payloadLength = _frameLength - 12;
+  delete[] _packetData;
+  _packetData = new char[payloadLength];
+  memcpy(_packetData, frame + 12, payloadLength - 1);
+  _packetData[payloadLength - 1] = '\0';
+  memcpy(_packetSource, frame + 1, 8);
+  
+  delete[] frame;
+  _frameLength = 0;
+  _frameHeaderProcessed = false;
+  
+  // return number of bytes in payload
+  return(payloadLength);
 }
 
 String XBee::getPacketSource() {
-  
+  char buff[17];
+  sprintf(buff, "%02X%02X%02X%02X%02X%02X%02X%02X", _packetSource[0], _packetSource[1], _packetSource[2], _packetSource[3],
+                                                    _packetSource[4], _packetSource[5], _packetSource[6], _packetSource[7]);
+  String str(buff);
+  return(str);
 }
 
 String XBee::getPacketData() {
-  
+  String str(_packetData);
+  return(str);
 }
 
 int16_t XBee::setPanId(uint8_t* panId) {
diff --git a/src/modules/XBee.h b/src/modules/XBee.h
index 559f8b85..8d96bc62 100644
--- a/src/modules/XBee.h
+++ b/src/modules/XBee.h
@@ -67,6 +67,11 @@ class XBee {
   private:
     Module* _mod;
     uint8_t _frameID;
+    size_t _frameLength;
+    bool _frameHeaderProcessed;
+    
+    char* _packetData;
+    uint8_t _packetSource[8];
     
     void sendApiFrame(uint8_t type, uint8_t id, const char* data);
     void sendApiFrame(uint8_t type, uint8_t id, uint8_t* data, uint16_t length);