ESP8266 watchdog reset (WDT) while long freq scan

[ESPboy-edu]

The peculiarity of ESP8266 is such that the chip SDK needs to call internal routines from time to time for stable operation and if this is not done, the chip reboots with WDT error.
SDK internal procedure calls occur in the following cases:

1. start of loop(){}
2. delay(n);
3. call ESP.wdtFeed();
   .Thus, when calling the procedure of frequency scanning from the library, WDT chip reboot occurs in case of long scanning (2-3sec).