From 1fb68d1e05d8ea6d65243c6166b116ec181d4644 Mon Sep 17 00:00:00 2001
From: Stefan Wahren <info@lategoodbye.de>
Date: Sun, 20 May 2012 03:35:04 +0200
Subject: [PATCH] Fixed primary address scan - scan only normal addresses
 (0-250) - show collisions in scan result

---
 bin/mbus-serial-scan.c | 36 +++++++++++++++++++++++++++++++-----
 1 file changed, 31 insertions(+), 5 deletions(-)

diff --git a/bin/mbus-serial-scan.c b/bin/mbus-serial-scan.c
index f0d1776..3d7c8bf 100644
--- a/bin/mbus-serial-scan.c
+++ b/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;
 
@@ -93,16 +94,41 @@ main(int argc, char **argv)
             printf("Scan failed. Could not send ping frame: %s\n", mbus_error_str());
             return 1;
         } 
+        
+        ret = mbus_recv_frame(handle, &reply);
 
-        if (mbus_recv_frame(handle, &reply) == -1)
+        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)
-                printf("\n");
+            /* check for more data (collision) */
+            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);
         }