Add quick wifi connect using saved AP parameters

Add quick wifi connect using saved AP parameters when ``SetOption56 0`` (#3189)

RELEASENOTES.md

@@ -72,3 +72,4 @@ The following binary downloads have been compiled with ESP8266/Arduino library c
 - Add support for up to four MQTT GroupTopics using the same optional Device Group names (#8014)
 - Add console command history (#7483, #8015)
 - Add support for longer template names
+- Add quick wifi connect using saved AP parameters when ``SetOption56 0`` (#3189)

tasmota/CHANGELOG.md

@@ -12,6 +12,7 @@
 - Add command ``Sensor10 0/1/2`` to control BH1750 resolution - 0 = High (default), 1 = High2, 2 = Low (#8016)
 - Add command ``Sensor10 31..254`` to control BH1750 measurement time which defaults to 69 (#8016)
 - Add command ``SetOption91 1`` to enable fading at startup / power on
+- Add quick wifi connect using saved AP parameters when ``SetOption56 0`` (#3189)
 
 ### 8.2.0.2 20200328
 

tasmota/settings.h

@@ -470,8 +470,10 @@ struct SYSCFG {
   uint8_t       bri_preset_low;            // F06
   uint8_t       bri_preset_high;           // F07
   int8_t        hum_comp;                  // F08
+  uint8_t       channel;                   // F09
+  uint8_t       bssid[6];                  // F0A
 
-  uint8_t       free_f09[175];             // F09
+  uint8_t       free_f10[168];             // F10
 
   uint16_t      pulse_counter_debounce_low;  // FB8
   uint16_t      pulse_counter_debounce_high; // FBA

tasmota/support_wifi.ino

@@ -401,6 +401,11 @@ void WifiCheckIp(void)
       Settings.ip_address[1] = (uint32_t)WiFi.gatewayIP();
       Settings.ip_address[2] = (uint32_t)WiFi.subnetMask();
       Settings.ip_address[3] = (uint32_t)WiFi.dnsIP();
+
+      // Save current AP parameters for quick reconnect
+      Settings.channel = WiFi.channel();
+      uint8_t *bssid = WiFi.BSSID();
+      memcpy((void*) &Settings.bssid, (void*) bssid, sizeof(Settings.bssid));
     }
     Wifi.status = WL_CONNECTED;
 #ifdef USE_DISCOVERY
@@ -423,6 +428,7 @@ void WifiCheckIp(void)
         break;
       case WL_NO_SSID_AVAIL:
         AddLog_P(LOG_LEVEL_INFO, S_LOG_WIFI, PSTR(D_CONNECT_FAILED_AP_NOT_REACHED));
+        Settings.channel = 0;  // Disable stored AP
         if (WIFI_WAIT == Settings.sta_config) {
           Wifi.retry = Wifi.retry_init;
         } else {
@@ -462,7 +468,7 @@ void WifiCheckIp(void)
         }
       } else {
         if (Wifi.retry_init == Wifi.retry) {
-          WifiBegin(3, 0);        // Select default SSID
+          WifiBegin(3, Settings.channel);  // Select default SSID
         }
         if ((Settings.sta_config != WIFI_WAIT) && ((Wifi.retry_init / 2) == Wifi.retry)) {
           WifiBegin(2, 0);        // Select alternate SSID
@@ -650,6 +656,8 @@ void WifiConnect(void)
   Wifi.retry = Wifi.retry_init;
   Wifi.counter = 1;
 
+  memcpy((void*) &Wifi.bssid, (void*) Settings.bssid, sizeof(Wifi.bssid));
+
 #ifdef WIFI_RF_PRE_INIT
   if (rf_pre_init_flag) {
     AddLog_P2(LOG_LEVEL_DEBUG, PSTR(D_LOG_WIFI "Pre-init done"));