WiFi

WiFi State Machine

WiFi STA states

  1. STA off -> ESPEASY_WIFI_DISCONNECTED
  2. STA connecting
  3. STA connected -> ESPEASY_WIFI_CONNECTED
  4. STA got IP -> ESPEASY_WIFI_GOT_IP
  5. STA connected && got IP -> ESPEASY_WIFI_SERVICES_INITIALIZED

N.B. the states are flags, meaning both “connected” and “got IP” must be set to be considered ESPEASY_WIFI_SERVICES_INITIALIZED

The flag wifiConnectAttemptNeeded indicates whether a new connect attempt is needed. This is set to true when:

  • Security settings have been saved with AP mode enabled. FIXME TD-er, this may not be the best check.
  • WiFi connect timeout reached & No client is connected to the AP mode of the node.
  • Wifi is reset
  • WiFi setup page has been loaded with SSID/pass values.

WiFi AP mode states

  1. AP on -> reset AP disable timer
  2. AP client connect/disconnect -> reset AP disable timer
  3. AP off -> AP disable timer = 0;

AP mode will be disabled when both apply:

  • AP disable timer (timerAPoff) expired
  • No client is connected to the AP.

AP mode will be enabled when at least one applies:

  • No valid WiFi settings
  • Start AP timer (timerAPstart) expired

Start AP timer is set or cleared at:

  • Set timerAPstart when “valid WiFi connection” state is observed.
  • Disable timerAPstart when ESPEASY_WIFI_SERVICES_INITIALIZED wifi state is reached.

Quick reconnect (using BSSID/channel of last connection) when both apply:

  • If wifi_connect_attempt < 3
  • lastBSSID is known

Change of wifi settings when both apply:

  • “other” settings valid
  • (wifi_connect_attempt % 2) == 0

Reset of wifi_connect_attempt to 0 when both apply:

  • connection successful
  • Connection stable (connected for > 5 minutes)

WiFi disconnect reasons

Beacon timeout (200)

For more information on the Beacon frame, see Wikipedia.

In short, the access point sends periodically a packet containing information about the network. This interval is typically 100 TU (102.4 msec). The ESP module is trying to listen to this beacon every time, but for a number of reasons it may miss a beacon frame. The timeout is longer than 100 TU, so it must miss a number of these beacon frames to report a beacon timeout. Reasons to miss such a beacon frame are:

  • too busy processing other blocking tasks (very likely)
  • access point not sending a beacon due to high traffic demands of others (depending on brand/model/settings)
  • RF disturbances (not likely given how often this occurs)
  • clock drift (not really likely)

So the “beacon timeout” is happening every now and then on the ESP nodes and ESPeasy will try to reconnect.