[WiFi] Allow force to B/G to improve WiFi stability.

See letscontrolit#2012 and discussion here: letscontrolit#1987 (comment)

src/ESPEasy-Globals.h

@@ -37,6 +37,7 @@
 #define DEFAULT_IP_BLOCK_LEVEL 1                // 0: ALL_ALLOWED  1: LOCAL_SUBNET_ALLOWED  2: ONLY_IP_RANGE_ALLOWED
 
 #define DEFAULT_WIFI_CONNECTION_TIMEOUT  10000  // minimum timeout in ms for WiFi to be connected.
+#define DEFAULT_WIFI_FORCE_BG_MODE       false  // when set, only allow to connect in 802.11B or G mode (not N)
 
 // --- Default Controller ------------------------------------------------------------------------------
 #define DEFAULT_CONTROLLER   false              // true or false enabled or disabled, set 1st controller defaults
@@ -548,6 +549,7 @@ bool showSettingsFileLayout = false;
   #include <WebServer.h>
   #include "SPIFFS.h"
   #include <rom/rtc.h>
+  #include "esp_wifi.h" // Needed to call ESP-IDF functions like esp_wifi_....
   WebServer WebServer(80);
   #ifdef FEATURE_MDNS
     #include <ESPmDNS.h>
@@ -723,6 +725,11 @@ struct SettingsStruct
   bool OldRulesEngine() {  return !getBitFromUL(VariousBits1, 3); }
   void OldRulesEngine(bool value) {  setBitToUL(VariousBits1, 3, !value); }
 
+  bool ForceWiFi_bg_mode() {  return getBitFromUL(VariousBits1, 4); }
+  void ForceWiFi_bg_mode(bool value) {  setBitToUL(VariousBits1, 4, value); }
+
+
+
 
   void validate() {
     if (UDPPort > 65535) UDPPort = 0;
@@ -825,6 +832,7 @@ struct SettingsStruct
     MQTTUseUnitNameAsClientId = 0;
     VariousBits1 = 0;
     OldRulesEngine(DEFAULT_RULES_OLDENGINE);
+    ForceWiFi_bg_mode(DEFAULT_WIFI_FORCE_BG_MODE);
   }
 
   void clearAll() {

src/ESPEasyWifi.ino

@@ -580,6 +580,33 @@ bool wifiConnectTimeoutReached() {
   return timeOutReached(last_wifi_connect_attempt_moment + DEFAULT_WIFI_CONNECTION_TIMEOUT + randomOffset_in_sec);
 }
 
+void setConnectionSpeed() {
+  #ifdef ESP8266
+  if (Settings.ForceWiFi_bg_mode() || wifi_connect_attempt > 10) {
+    WiFi.setPhyMode(WIFI_PHY_MODE_11G);
+  } else {
+    WiFi.setPhyMode(WIFI_PHY_MODE_11N);
+  }
+  #endif
+
+  // Does not (yet) work, so commented out.
+  #ifdef ESP32
+  uint8_t protocol = WIFI_PROTOCOL_11B | WIFI_PROTOCOL_11G; // Default to BG
+  if (!Settings.ForceWiFi_bg_mode() || wifi_connect_attempt > 10) {
+    // Set to use BGN
+    protocol |= WIFI_PROTOCOL_11N;
+  }
+  if (WifiIsSTA(WiFi.getMode())) {
+    esp_wifi_set_protocol(WIFI_IF_STA, protocol);
+  }
+  if (WifiIsAP(WiFi.getMode())) {
+    esp_wifi_set_protocol(WIFI_IF_AP, protocol);
+  }
+  #endif
+
+
+}
+
 void setupStaticIPconfig() {
   setUseStaticIP(useStaticIP());
   if (!useStaticIP()) return;
@@ -637,6 +664,7 @@ bool tryConnectWiFi() {
     addLog(LOG_LEVEL_INFO, log);
   }
   setupStaticIPconfig();
+  setConnectionSpeed();
   last_wifi_connect_attempt_moment = millis();
   switch (wifi_connect_attempt) {
     case 0:

src/WebServer.ino

@@ -3359,6 +3359,10 @@ void html_B(const String& text) {
   wrap_html_tag("b", text);
 }
 
+void html_I(const String& text) {
+  wrap_html_tag("i", text);
+}
+
 void html_U(const String& text) {
   wrap_html_tag("u", text);
 }
@@ -4671,6 +4675,7 @@ void handle_advanced() {
     Settings.Latitude = getFormItemFloat(F("latitude"));
     Settings.Longitude = getFormItemFloat(F("longitude"));
     Settings.OldRulesEngine(isFormItemChecked(F("oldrulesengine")));
+    Settings.ForceWiFi_bg_mode(isFormItemChecked(F("forcewifi_bg")));
 
     addHtmlError(SaveSettings());
     if (systemTimePresent())
@@ -4750,6 +4755,13 @@ void handle_advanced() {
   addFormCheckBox_disabled(F("Use SSDP"), F("usessdp"), Settings.UseSSDP);
 
   addFormNumericBox(F("Connection Failure Threshold"), F("cft"), Settings.ConnectionFailuresThreshold, 0, 100);
+#ifdef ESP8266
+  addFormCheckBox(F("Force WiFi B/G"), F("forcewifi_bg"), Settings.ForceWiFi_bg_mode());
+#endif
+#ifdef ESP32
+  // Disabled for now, since it is not working properly.
+  addFormCheckBox_disabled(F("Force WiFi B/G"), F("forcewifi_bg"), Settings.ForceWiFi_bg_mode());
+#endif
 
   addFormNumericBox(F("I2C ClockStretchLimit"), F("wireclockstretchlimit"), Settings.WireClockStretchLimit);   //TODO define limits
   #if defined(FEATURE_ARDUINO_OTA)