Change byte order of the MAC in the access point name.

fixes openbikesensor#315

src/configServer.cpp

@@ -765,12 +765,23 @@ void startServer(ObsConfig *obsConfig) {
   theObsConfig = obsConfig;
 
   const uint64_t chipid_num = ESP.getEfuseMac();
-  String esp_chipid = String((uint16_t)(chipid_num >> 32), HEX);
-  esp_chipid += String((uint32_t)chipid_num, HEX);
-  esp_chipid.toUpperCase();
-  OBS_ID = "OpenBikeSensor-" + esp_chipid;
-  OBS_ID_SHORT = "OBS-" + String((uint16_t)(ESP.getEfuseMac() >> 32), HEX);
-  OBS_ID_SHORT.toUpperCase();
+
+  uint64_t chipid_be = 0;
+  for(int i=0; i<48; i=i+8) {
+    chipid_be <<= 8;
+    chipid_be |= ((chipid_num >> i) & 0xff);
+  }
+  /*
+    FIXME: workaround as the MAC of the AP is increased by one
+    could not yet figure out the reason, as WiFi.softAP is
+    called with OBS_ID as value for the ssid
+  */
+  chipid_be++;
+
+  char esp_chipid[28];
+  snprintf(esp_chipid, sizeof(esp_chipid), "OpenBikeSensor-%llX", chipid_be);
+  OBS_ID = String(esp_chipid);
+  OBS_ID_SHORT = "OBS-" + OBS_ID.substring(15,19);
 
   displayTest->clear();
   displayTest->showTextOnGrid(0, 0, "Ver.:");