updated exmaple section for LORAWAN

docs/zh_CN/module/lorawan.md

@@ -54,83 +54,78 @@ LoRaWAN**默认的串口配置：**
 
 ### Arduino IDE
 
-这是主从LORA模块点对点通信的例程，模块与M5Core之间通过AT指令通讯。
+这是两个 LoRaWAN 模块之间通信的例程。
 
-*具体例程请点击[这里](https://github.com/m5stack/M5-ProductExampleCodes/tree/master/Module/LORAWAN/Arduino)。*
+**功能：** 按下按键 B，设置模块工作在 433MHz 频段，并发送字符串 “Hello World”; 按下按键 C，设置模块工作在 868MHz 频段，并发送字符串 “Hello World”; 按下按键 A，Core 清屏。
+
+**注意：** 在编译程序之前需要将 `LoRaWan for M5Stack.rar` 解压到路径 `C:\Users\<user_name>\Documents\Arduino\libraries` 下。
+
+*以下仅为用法示意，并不完整。如果需要完整例程请点击[这里](https://github.com/m5stack/M5-ProductExampleCodes/tree/master/Module/LORAWAN/Arduino)。*
 
 ```arduino
 /*
-    Master.ino
+    device_A.ino
 */
-
 #include <M5Stack.h>
+#include <LoRaWan.h>
 
-// entry test mode
-String cmd_test_mode = "AT+Mode=Test";
-// Configure the modem,like Freq, SF, BW, Preamble length, TX output power
-String cmd_rfconf = "AT+TEST=RFCFG,472.3,8,250,8,8,20";
-// send data as HEX format
-String cmd_send_data = "AT+TEST=TXLRPKT,\"30 31 32 33 34 35\"";
+#define SerialUSB Serial
 
-void setup() {
-  M5.begin();
-  Serial.begin(9600);
-  Serial2.begin(9600, SERIAL_8N1, 16, 17);
+// declaration
+M5.begin();
+SerialUSB.begin(9600);
+lora.init();
+delay(2000); // must delay for lorawan power on
 
-  delay(1000);// delay for lorawan power on
-  /* LoRaWAN Init */
-  Serial2.println(cmd_test_mode);
-  delay(500);
-  Serial2.println(cmd_rfconf);
-  delay(500);
-}
+// 433MHz frequency initialization
+lora.initP2PMode(433, SF12, BW500, 8, 8, 20);
 
-void loop() {
-  if(M5.BtnA.wasPressed()) {
-    Serial2.println(cmd_send_data);
-    Serial.println(cmd_send_data);
-  }
-  M5.update();
-}
+// 868MHz frequency initialization
+lora.initP2PMode(868, SF12, BW500, 8, 8, 20);
+
+// send string
+lora.transferPacketP2PMode("hello world");
+
+// receive data
+short length = 0;
+short rssi = 0;
+memset(buffer, 0, 128);
+length = lora.receivePacketP2PMode(buffer, 128, &rssi, 1);
 ```
 
 ```arduino
 /*
-    Slaver.ino
+    device_B.ino
 */
-
 #include <M5Stack.h>
+#include <LoRaWan.h>
 
-// entry test mode
-String cmd_test_mode = "AT+Mode=Test";
-// Configure the modem,like Freq, SF, BW, Preamble length
-String cmd_rfconf = "AT+TEST=RFCFG,472.3,8,250,8,8,20";
-// allow to receive data
-String cmd_receive_data = "AT+TEST=RXLRPKT";
+#define SerialUSB Serial
 
-void setup() {
-  M5.begin();
-  Serial.begin(9600);
-  Serial2.begin(9600, SERIAL_8N1, 16, 17);
-  delay(1000);// delay for lorawan power on
-  /* LoRaWAN Init */
-  Serial2.println(cmd_test_mode);
-  delay(500);
-  Serial2.println(cmd_rfconf);
-  delay(500);
-  Serial2.println(cmd_receive_data);
-  delay(500);
-}
+// declaration
+M5.begin();
+SerialUSB.begin(9600);
+lora.init();
+delay(2000); // must delay for lorawan power on
 
-void loop() {
-  if(Serial2.available()) {
-    int ch = Serial2.read();
-    M5.Lcd.print((char)ch);
-    Serial.write(ch);
-  }
-}
+// 433MHz frequency initialization
+lora.initP2PMode(433, SF12, BW500, 8, 8, 20);
+
+// 868MHz frequency initialization
+lora.initP2PMode(868, SF12, BW500, 8, 8, 20);
+
+// send string
+lora.transferPacketP2PMode("hello world");
+
+// receive data
+short length = 0;
+short rssi = 0;
+memset(buffer, 0, 128);
+length = lora.receivePacketP2PMode(buffer, 128, &rssi, 1);
 ```
 
+<img src="assets/img/product_pics/module/module_example/LORAWAN/example_module_lorawan_01.png">
+
 ## 原理图
 
 <img src="assets/img/product_pics/module/lorawan_sch.png">