Diff: main.cpp

Revision:

0:6380a1c94d6c

Child:

1:c994530bdb3d

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Thu Nov 25 18:58:24 2021 +0000
@@ -0,0 +1,196 @@
+/*
+ * Program implements MQTT client on a NUCLEO-L476RG board
+ * using arm mbed-mqtt library and ESP-WROOM-02 WiFi modem.
+ *
+ * University of Belgrade - School of Electrical Engineering
+ * Department of Electronics
+ * Bulevar Kralja Aleksandra 73, 11120 Belgrade, Serbia
+ *
+ * November 2021.
+ *
+ */
+
+#include "mbed.h"
+#include "mb_pins.h"
+#include "platform/mbed_thread.h"
+#include "MQTTClientMbedOs.h"
+
+
+// LED2 blinking rate:
+#define BLINKING_RATE_MS                                                     250
+// Scaler to 3v3L
+#define VOLTAGE_SCALER                                                      3.3f
+// Client yield timeout in miliseconds:
+#define YIELD_TIMEOUT_MS                                                    1000
+// Maximum number of networks to scan for:
+#define MAX_NETWORKS                                                          15
+// Small delay for network information printing:
+#define PRINTF_DELAY_MS                                                       10
+
+
+// Left potentiometer:
+AnalogIn pot1(MB_POT1);
+// Left button on the motherboard:
+InterruptIn sw1(MB_SW1);
+// Right LED on the motherboard:
+DigitalOut led2(MB_LED2);
+// WiFi network handler:
+WiFiInterface *wifi;
+// Creating TCP socket:
+TCPSocket socket;
+// Creating MQTT client using the TCP socket;
+MQTTClient client(&socket);
+// Message handler:
+MQTT::Message message;
+
+char* topic = "mbed-sample-pub";
+char* topic_sub = "mbed-sample-sub";
+// Counter of arrived messages:
+int arrivedcount = 0;
+// Flag indicating that button is not pressed:
+int button_pressed=0;
+
+// Returning a string for a provided network encryption: 
+const char *sec2str(nsapi_security_t sec)
+{
+    switch (sec) 
+    {
+        case NSAPI_SECURITY_NONE:
+            return "None";
+        case NSAPI_SECURITY_WEP:
+            return "WEP";
+        case NSAPI_SECURITY_WPA:
+            return "WPA";
+        case NSAPI_SECURITY_WPA2:
+            return "WPA2";
+        case NSAPI_SECURITY_WPA_WPA2:
+            return "WPA/WPA2";
+        case NSAPI_SECURITY_UNKNOWN:
+        default:
+            return "Unknown";
+    }
+}
+
+int scan_demo(WiFiInterface *wifi)
+{
+    // Creating an access point
+    WiFiAccessPoint *ap;
+
+    printf("Scan:\n");
+
+    int count = wifi->scan(NULL,0);
+
+    if (count <= 0)
+    {
+        printf("scan() failed with return value: %d\n", count);
+        return 0;
+    }
+
+    // Limit number of network arbitrary to 15
+    count = count < MAX_NETWORKS ? count : MAX_NETWORKS;
+    
+    // Create a new object, array of WiFi APs, and assign it to ap variable:
+    ap = new WiFiAccessPoint[count];
+    count = wifi->scan(ap, count);
+
+    if (count <= 0) 
+    {
+        printf("scan() failed with return value: %d\n", count);
+        return 0;
+    }
+    
+    // Print network information:
+    for (int i = 0; i < count; i++) 
+    {
+        printf("Network: %s secured: %s BSSID: %hhX:%hhX:%hhX:%hhx:%hhx:%hhx RSSI: %hhd Ch: %hhd\n", ap[i].get_ssid(),
+               sec2str(ap[i].get_security()), ap[i].get_bssid()[0], ap[i].get_bssid()[1], ap[i].get_bssid()[2],
+               ap[i].get_bssid()[3], ap[i].get_bssid()[4], ap[i].get_bssid()[5], ap[i].get_rssi(), ap[i].get_channel());
+        thread_sleep_for(PRINTF_DELAY_MS);
+    }
+    printf("%d networks available.\n", count);
+
+    delete[] ap;
+    return count;
+}
+
+void messageArrived(MQTT::MessageData& md)
+{
+    MQTT::Message &message = md.message;
+    //printf("Message arrived: qos %d, retained %d, dup %d, packetid %d\r\n", message.qos, message.retained, message.dup, message.id);
+    printf("Message from the browser: %.*s\r\n", message.payloadlen, (char*)message.payload);
+    ++arrivedcount;
+}
+
+void buttonFunction() {
+    
+    button_pressed=1;
+   
+}
+
+int main()
+{
+    sw1.fall(&buttonFunction);    
+    const char* hostname = "broker.hivemq.com";
+    int port = 1883;    
+    // Network interface
+    
+    wifi = WiFiInterface::get_default_instance();
+    if (!wifi) {
+        printf("ERROR: No WiFiInterface found.\n");
+        return -1;
+    }
+
+    int count = scan_demo(wifi);
+    if (count == 0) {
+        printf("No WIFI APs found - can't continue further.\n");
+        return -1;
+    }
+
+    printf("\nConnecting to %s...\n", MBED_CONF_APP_WIFI_SSID);
+    int ret = wifi->connect(MBED_CONF_APP_WIFI_SSID, MBED_CONF_APP_WIFI_PASSWORD, NSAPI_SECURITY_WPA_WPA2);
+    if (ret != 0) {
+        printf("\nConnection error: %d\n", ret);
+        return -1;
+    }
+
+    printf("Success\n\n");
+    printf("MAC: %s\n", wifi->get_mac_address());
+    printf("IP: %s\n", wifi->get_ip_address());
+    printf("Netmask: %s\n", wifi->get_netmask());
+    printf("Gateway: %s\n", wifi->get_gateway());
+    printf("RSSI: %d\n\n", wifi->get_rssi());   
+     
+    socket.open(wifi);
+    socket.connect(hostname, port);
+    
+    MQTTPacket_connectData data = MQTTPacket_connectData_initializer;
+    data.MQTTVersion = 3;
+    data.clientID.cstring = "NUCLEO-L476RG-60";
+    
+    int rc=0;
+    if ((rc = client.connect(data)) != 0)
+        printf("rc from MQTT connect is %d\r\n", rc);
+
+    if ((rc = client.subscribe(topic_sub, MQTT::QOS2, messageArrived)) != 0)
+        printf("rc from MQTT subscribe is %d\r\n", rc);
+      
+    while (true) {
+        // Show that the loop is running by switching motherboard LED2:
+        led2 = !led2;
+        thread_sleep_for(BLINKING_RATE_MS);
+        if (button_pressed==1) {
+            button_pressed=0;      
+            // QoS 0
+            char buf[100];
+            sprintf(buf, "V(POT1) = %1.2f\r\n", pot1*VOLTAGE_SCALER);
+            message.qos = MQTT::QOS0;
+            message.retained = false;
+            message.dup = false;
+            message.payload = (void*)buf;
+            message.payloadlen = strlen(buf)+1;
+            client.publish(topic, message);
+        }
+        // Need to call yield API to maintain connection:
+        client.yield(YIELD_TIMEOUT_MS);
+    }
+}
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