Initial commit, getting all the stuff from PlatformIO

.pio/libdeps/esp32dev/PicoMQTT/examples/w5500_client/w5500_client.ino

@@ -0,0 +1,48 @@
+// Platform compatibility: espressif8266
+
+#include <Arduino.h>
+#include <Ethernet.h>
+
+#include <PicoMQTT.h>
+
+byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
+
+EthernetClient client;
+PicoMQTT::Client mqtt(client, "broker.hivemq.com");
+
+unsigned long last_publish_time = 0;
+int greeting_number = 1;
+
+void setup() {
+    Serial.begin(115200);
+
+    Serial.println("Connecting to network...");
+    Ethernet.init(5); // ss pin
+    while (!Ethernet.begin(mac)) {
+        Serial.println("Failed, retrying...");
+    }
+    Serial.println(Ethernet.localIP());
+
+    // Subscribe to a topic and attach a callback
+    mqtt.subscribe("picomqtt/#", [](const char * topic, const char * payload) {
+        // payload might be binary, but PicoMQTT guarantees that it's zero-terminated
+        Serial.printf("Received message in topic '%s': %s\n", topic, payload);
+    });
+
+    mqtt.begin();
+}
+
+void loop() {
+    mqtt.loop();
+
+    // Publish a greeting message every 3 seconds.
+    if (millis() - last_publish_time >= 3000) {
+        // We're publishing to a topic, which we're subscribed too.
+        // The broker should deliver the messages back to us.
+        String topic = "picomqtt/esp-" + WiFi.macAddress();
+        String message = "Hello #" + String(greeting_number++);
+        Serial.printf("Publishing message in topic '%s': %s\n", topic.c_str(), message.c_str());
+        mqtt.publish(topic, message);
+        last_publish_time = millis();
+    }
+}