Fixed primary address scan

- scan only normal addresses (0-250)
- show collisions in scan result

bin/mbus-serial-scan.c

@@ -28,6 +28,7 @@ main(int argc, char **argv)
     mbus_handle *handle;
     char *device;
     int address, baudrate = 9600;
+    int ret;
 
     if (argc == 2)
     {
@@ -76,7 +77,7 @@ main(int argc, char **argv)
     if (debug)
         printf("Scanning primary addresses:\n");
 
-    for (address = 0; address < 254; address++)
+    for (address = 0; address <= 250; address++)
     {
         mbus_frame reply;
 
@@ -94,15 +95,40 @@ main(int argc, char **argv)
             return 1;
         } 
         
-        if (mbus_recv_frame(handle, &reply) == -1)
+        ret = mbus_recv_frame(handle, &reply);
+
+        if (ret == -1)
         {
             continue;
         }
         
+        if (debug)
+            printf("\n");
+        
+        if (ret == -2)
+        {
+            /* check for more data (collision) */
+            while (mbus_recv_frame(handle, &reply) != -1);
+            
+            printf("Collision at address %d\n", address);
+            
+            continue;
+        } 
+
         if (mbus_frame_type(&reply) == MBUS_FRAME_TYPE_ACK)
         {
-            if (debug)
+            /* check for more data (collision) */
-                printf("\n");
+            while (mbus_recv_frame(handle, &reply) != -1)
+            {
+                ret = -2;
+            }
+    
+            if (ret == -2)
+            {
+                printf("Collision at address %d\n", address);
+                
+                continue;
+            }
                 
             printf("Found a M-Bus device at address %d\n", address);
         }