Adds Ethernet Examples

examples/TCP/EthernetModbusClientToggle/EthernetModbusClientToggle.ino

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+/*
+  Ethernet Modbus TCP Client Toggle
+
+  This sketch toggles the coil of a Modbus TCP server connected
+  on and off every second.
+
+  Circuit:
+   - Any Arduino MKR Board
+   - MKR ETH Shield
+
+  created 16 July 2018
+  by Sandeep Mistry
+*/
+
+#include <SPI.h>
+#include <Ethernet.h>
+
+#include <ArduinoRS485.h> // ArduinoModbus depends on the ArduinoRS485 library
+#include <ArduinoModbus.h>
+
+// Enter a MAC address for your controller below.
+// Newer Ethernet shields have a MAC address printed on a sticker on the shield
+// The IP address will be dependent on your local network:
+byte mac[] = {
+  0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED
+};
+IPAddress ip(192, 168, 1, 177);
+
+EthernetClient ethClient;
+ModbusTCPClient modbusTCPClient(ethClient);
+
+IPAddress server(192, 168, 1, 10); // update with the IP Address of your Modbus server
+
+void setup() {
+  //Initialize serial and wait for port to open:
+  Serial.begin(9600);
+  while (!Serial) {
+    ; // wait for serial port to connect. Needed for native USB port only
+  }
+
+  // start the Ethernet connection and the server:
+  Ethernet.begin(mac, ip);
+
+  // Check for Ethernet hardware present
+  if (Ethernet.hardwareStatus() == EthernetNoHardware) {
+    Serial.println("Ethernet shield was not found.  Sorry, can't run without hardware. :(");
+    while (true) {
+      delay(1); // do nothing, no point running without Ethernet hardware
+    }
+  }
+  if (Ethernet.linkStatus() == LinkOFF) {
+    Serial.println("Ethernet cable is not connected.");
+  }
+}
+
+void loop() {
+  if (!modbusTCPClient.connected()) {
+    // client not connected, start the Modbus TCP client
+    Serial.println("Attempting to connect to Modbus TCP server");
+
+    if (!modbusTCPClient.begin(server, 502)) {
+      Serial.println("Modbus TCP Client failed to connect!");
+    } else {
+      Serial.println("Modbus TCP Client connected");
+    }
+  } else {
+    // client connected
+
+    // write the value of 0x01, to the coil at address 0x00
+    if (!modbusTCPClient.coilWrite(0x00, 0x01)) {
+      Serial.print("Failed to write coil! ");
+      Serial.println(modbusTCPClient.lastError());
+    }
+
+    // wait for 1 second
+    delay(1000);
+
+    // write the value of 0x00, to the coil at address 0x00
+    if (!modbusTCPClient.coilWrite(0x00, 0x00)) {
+      Serial.print("Failed to write coil! ");
+      Serial.println(modbusTCPClient.lastError());
+    }
+
+    // wait for 1 second
+    delay(1000);
+  }
+}

examples/TCP/EthernetModbusServerLED/EthernetModbusServerLED.ino

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+/*
+  Ethernet Modbus TCP Server LED
+
+  This sketch creates a Modbus TCP Server with a simulated coil.
+  The value of the simulated coil is set on the LED
+
+  Circuit:
+   - Any Arduino MKR Board
+   - MKR ETH Shield
+
+  created 16 July 2018
+  by Sandeep Mistry
+*/
+
+#include <SPI.h>
+#include <Ethernet.h>
+
+#include <ArduinoRS485.h> // ArduinoModbus depends on the ArduinoRS485 library
+#include <ArduinoModbus.h>
+
+// Enter a MAC address for your controller below.
+// Newer Ethernet shields have a MAC address printed on a sticker on the shield
+// The IP address will be dependent on your local network:
+byte mac[] = {
+  0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED
+};
+IPAddress ip(192, 168, 1, 177);
+
+EthernetServer ethServer(502);
+
+ModbusTCPServer modbusTCPServer;
+
+const int ledPin = LED_BUILTIN;
+
+void setup() {
+  // You can use Ethernet.init(pin) to configure the CS pin
+  //Ethernet.init(10);  // Most Arduino shields
+  //Ethernet.init(5);   // MKR ETH shield
+  //Ethernet.init(0);   // Teensy 2.0
+  //Ethernet.init(20);  // Teensy++ 2.0
+  //Ethernet.init(15);  // ESP8266 with Adafruit Featherwing Ethernet
+  //Ethernet.init(33);  // ESP32 with Adafruit Featherwing Ethernet
+
+  // Open serial communications and wait for port to open:
+  Serial.begin(9600);
+  while (!Serial) {
+    ; // wait for serial port to connect. Needed for native USB port only
+  }
+  Serial.println("Ethernet Modbus TCP Example");
+
+  // start the Ethernet connection and the server:
+  Ethernet.begin(mac, ip);
+
+  // Check for Ethernet hardware present
+  if (Ethernet.hardwareStatus() == EthernetNoHardware) {
+    Serial.println("Ethernet shield was not found.  Sorry, can't run without hardware. :(");
+    while (true) {
+      delay(1); // do nothing, no point running without Ethernet hardware
+    }
+  }
+  if (Ethernet.linkStatus() == LinkOFF) {
+    Serial.println("Ethernet cable is not connected.");
+  }
+
+  // start the server
+  ethServer.begin();
+
+  // start the Modbus TCP server
+  if (!modbusTCPServer.begin()) {
+    Serial.println("Failed to start Modbus TCP Server!");
+    while (1);
+  }
+
+  // configure the LED
+  pinMode(ledPin, OUTPUT);
+  digitalWrite(ledPin, LOW);
+
+  // configure a single coil at address 0x00
+  modbusTCPServer.configureCoils(0x00, 1);
+}
+
+void loop() {
+  // listen for incoming clients
+  EthernetClient client = ethServer.available();
+
+  if (client) {
+    // a new client connected
+    Serial.println("new client");
+
+    // let the Modbus TCP accept the connection 
+    modbusTCPServer.accept(client);
+
+    while (client.connected()) {
+      // poll for Modbus TCP requests, while client connected
+      modbusTCPServer.poll();
+
+      // update the LED
+      updateLED();
+    }
+
+    Serial.println("client disconnected");
+  }
+}
+
+void updateLED() {
+  // read the current value of the coil
+  int coilValue = modbusTCPServer.coilRead(0x00);
+
+  if (coilValue) {
+    // coil value set, turn LED on
+    digitalWrite(ledPin, HIGH);
+  } else {
+    // coild value clear, turn LED off
+    digitalWrite(ledPin, LOW);
+  }
+}