Improve gitignore for PlatformIO + macOS

.gitignore

@@ -0,0 +1,11 @@
+#
+# macOS junk
+.DS_Store
+**/.DS_Store
+
+# PlatformIO build + deps (ANY folder)
+**/.pio/
+.platformio/
+
+# VS Code (all subprojects)
+**/.vscode/

Source/ports/OpEnerTeensy/.gitignore

@@ -1,5 +0,0 @@
-.pio
-.vscode/.browse.c_cpp.db*
-.vscode/c_cpp_properties.json
-.vscode/launch.json
-.vscode/ipch

Source/ports/OpEnerTeensy/src/main.cpp

@@ -1,21 +1,59 @@
 #include <Arduino.h>
+#include <QNEthernet.h>
 
-// put function declarations here:
-int myFunction(int, int);
+using namespace qindesign::network;
+
+// Network config
+IPAddress ip(192, 168, 1, 177);   // change to your network
+IPAddress gateway(192, 168, 1, 1);
+IPAddress subnet(255, 255, 255, 0);
+
+EthernetUDP udp;
+const uint16_t localPort = 2222;   // EtherNet/IP uses 2222 (good test)
 
 void setup() {
-  // put your setup code here, to run once:
-  int result = myFunction(2, 3);
+    Serial.begin(115200);
+    delay(2000);
+
+    Serial.println("Starting Ethernet...");
+
+    Ethernet.begin(ip, subnet, gateway);
+
+    if (!Ethernet.linkStatus()) {
+        Serial.println("Ethernet cable not connected!");
+    }
+
+    Serial.print("IP: ");
+    Serial.println(Ethernet.localIP());
+
+    udp.begin(localPort);
+
+    Serial.print("Listening on UDP port: ");
+    Serial.println(localPort);
 }
 
 void loop() {
-  // put your main code here, to run repeatedly:
-  int data = myFunction(50,1);
-  Serial.print((int)data); 
-  delay(1000);
-}
+    int packetSize = udp.parsePacket();
 
-// put function definitions here:
-int myFunction(int x, int y) {
-  return x + y;
+    if (packetSize) {
+        Serial.print("Received packet: ");
+        Serial.println(packetSize);
+
+        char buffer[512];
+        int len = udp.read(buffer, sizeof(buffer));
+
+        if (len > 0) {
+            buffer[len] = 0;
+        }
+
+        Serial.print("Data: ");
+        Serial.println(buffer);
+
+        // Echo back
+        udp.beginPacket(udp.remoteIP(), udp.remotePort());
+        udp.write((const uint8_t*)"ACK", 3);
+        udp.endPacket();
+
+        Serial.println("Sent ACK");
+    }
 }