ScanNetworks seems to disconnect established TCP connections ?

Hardware Arduino WiFi Rev2
1

Hi there

I recently ported a well working project from Arduino Uno to the Arduino Uno Wifi. So far so good.
The Arduino connects well to my Wifi AP and establishes properly a TCP socket to my server. Data exchange performs well both ways.
Then in the suite of events I happen to perform a ScanNetworks; which terminates well (I can see the expected output on the serial line)
But then I cannot write anymore to the TCP socket, which seems disconnected.
Any clue ?
Thanks

2

I manage to isolate the interesting part of the code (full project available on github - see link from my profile)

in setup :

WiFiClient WiClient;

...

WiFi.begin(ssid[CurrentAP].c_str(), pass[CurrentAP].c_str());
WiClient.connect (host, port);

// all is fine, i can read, write as necessary

...

ecran.print (WiClient.status()); // output shows 4
numSsid = WiFi.scanNetworks();
ecran.print (WiClient.status()); // output shows 0

I do not know where to find the return value meanings for the status method, but I bet 0 means something like disconnected. The fact that the status changes is itself not good sign...
Any WiClient.write I perform later returns 0.

Someone knows how to scan without disconnecting established connections ? I remember playing with an ESP8266 directly, I could switch from Data to Command mode back and forth without such issue...

3

Solved

Actually, ScanNetworks does disconnects the WIFI from the Access Point.

So in order to have everything work fine I close the socket first, perform the scan, reconnect to the AP and then the socket itself :

WiClient.stop();
...
numSsid = WiFi.scanNetworks();
...
WifiStatus = WiFi.begin(ssid, pass);
...
WiClient.connect (host, port);

On the other side, I also closed the socket properly, then perform an accept to wait for the arduino to reconnect.

This behaviour of ScanNetwork is different here than other WIFI chips I had tested, and is not documented. Once you know it...