добавлена проверка - не превышает ли номер вывода из аргумента функции общее кол-во выводов

libraries/SoftwareSerial/src/SoftwareSerial.cpp

@@ -228,6 +228,18 @@ void SoftwareSerial::begin(long speed)
   // delays are empirical values here
   _rx_delay_centering = _rx_delay_intrabit = _rx_delay_stopbit = _tx_delay = 0;
 
+  // if pins exceeds the total number of pins, return with zero delays - it blocks further library work
+  if ((_transmitPin >= pinCommonQty()))
+  {
+    ErrorMsgHandler("SoftwareSerial.begin(): Tx pin number exceeds the total number of pins");
+    return;
+  }
+  if ((_receivePin >= pinCommonQty()))
+  {
+    ErrorMsgHandler("SoftwareSerial.begin(): Rx pin number exceeds the total number of pins");
+    return;
+  }
+
   // limit speed
   if (speed > MAX_SOFT_SERIAL_SPEED) speed = MAX_SOFT_SERIAL_SPEED;
   if (speed < MIN_SOFT_SERIAL_SPEED) speed = MIN_SOFT_SERIAL_SPEED;