Revision 1:c994530bdb3d, committed 2021-11-27

Comitter:

tzwell

Date:

Sat Nov 27 20:33:49 2021 +0000

Parent:

0:6380a1c94d6c

Commit message:

Commented in more detail

Changed in this revision

diff -r 6380a1c94d6c -r c994530bdb3d main.cpp
--- a/main.cpp	Thu Nov 25 18:58:24 2021 +0000
+++ b/main.cpp	Sat Nov 27 20:33:49 2021 +0000
@@ -34,7 +34,7 @@
 InterruptIn sw1(MB_SW1);
 // Right LED on the motherboard:
 DigitalOut led2(MB_LED2);
-// WiFi network handler:
+// Pointer to a WiFi network object:
 WiFiInterface *wifi;
 // Creating TCP socket:
 TCPSocket socket;
@@ -49,7 +49,9 @@
 int arrivedcount = 0;
 // Flag indicating that button is not pressed:
 int button_pressed=0;
-
+// HiveMQ broker connectivity information:
+const char* hostname = "broker.hivemq.com";
+int port = 1883;
 // Returning a string for a provided network encryption: 
 const char *sec2str(nsapi_security_t sec)
 {
@@ -71,35 +73,35 @@
     }
 }
 
-int scan_demo(WiFiInterface *wifi)
+int scan_networks(WiFiInterface *wifi)
 {
-    // Creating an access point
-    WiFiAccessPoint *ap;
-
     printf("Scan:\n");
-
-    int count = wifi->scan(NULL,0);
-
+    
+    // Scan only for the number of networks, first parameter is NULL:
+    int count = wifi->scan(NULL, 0);
+    // If there are no networks, count == 0, if there is an error, counter < 0:
     if (count <= 0)
     {
         printf("scan() failed with return value: %d\n", count);
         return 0;
     }
 
-    // Limit number of network arbitrary to 15
+    // Limit number of network arbitrary to some reasonable number:
     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];
+    // Create a local pointer to an object, which is an array of WiFi APs:
+    WiFiAccessPoint *ap = new WiFiAccessPoint[count];
+    // Now scan again for 'count' networks and populate the array of APs:
     count = wifi->scan(ap, count);
-
+    
+    // This time, the number of entries to 'ap' is returned:
     if (count <= 0) 
     {
         printf("scan() failed with return value: %d\n", count);
         return 0;
     }
     
-    // Print network information:
+    // Print out the parameters of each AP:
     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(),
@@ -108,7 +110,9 @@
         thread_sleep_for(PRINTF_DELAY_MS);
     }
     printf("%d networks available.\n", count);
-
+    
+    // Since 'ap' is dynamically allocated pointer to the array of objects, it
+    // needs to be deleted:
     delete[] ap;
     return count;
 }
@@ -129,45 +133,51 @@
 
 int main()
 {
-    sw1.fall(&buttonFunction);    
-    const char* hostname = "broker.hivemq.com";
-    int port = 1883;    
-    // Network interface
+    // Set the interrupt event:
+    sw1.fall(&buttonFunction); 
     
+    // Create a default network interface:
     wifi = WiFiInterface::get_default_instance();
     if (!wifi) {
         printf("ERROR: No WiFiInterface found.\n");
         return -1;
     }
-
-    int count = scan_demo(wifi);
+    
+    // Scan for available networks and aquire information about Access Points:
+    int count = scan_networks(wifi);
     if (count == 0) {
         printf("No WIFI APs found - can't continue further.\n");
         return -1;
     }
-
+    
+    // Connect to the network with the parameters specified in 'mbed_app.json':
     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;
     }
-
+    
+    // Print out the information aquired:
     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());   
-     
+    
+    // Open TCP socket using WiFi network interface:
     socket.open(wifi);
+    // Connect to the HiveMQ broker:
     socket.connect(hostname, port);
-    
+    // Fill connect data with default values:
     MQTTPacket_connectData data = MQTTPacket_connectData_initializer;
+    // Change only ID and protocol version:
     data.MQTTVersion = 3;
     data.clientID.cstring = "NUCLEO-L476RG-60";
     
-    int rc=0;
+    // Connect the 
+    int rc = 0;
     if ((rc = client.connect(data)) != 0)
         printf("rc from MQTT connect is %d\r\n", rc);