fix: check initalize AssociationTableData

src/knx/association_table_object.cpp

@@ -53,6 +53,7 @@ void AssociationTableObject::prepareBinarySearch()
     // we iterate through all ASAP
     // the first n ASAP are sorted (strictly increasing number), these are assigning sending TSAP
     // the remaining ASAP have to be all repetitions, otherwise we set sortedEntryCount to 0, which forces linear search 
+    if(_tableData != nullptr) {
         for (uint16_t idx = 0; idx < entryCount(); idx++)
         {
             currentASAP = getASAP(idx);
@@ -89,6 +90,7 @@ void AssociationTableObject::prepareBinarySearch()
         // in case complete table is strictly increasing
         if (lookupIdx == 0 && sortedEntryCount == 0)
             sortedEntryCount = entryCount();
+    } 
 #endif    
 }