diff --git a/cores/arduino/HardwareSerial.cpp b/cores/arduino/HardwareSerial.cpp
index 284d8fc..cdd7b64 100644
--- a/cores/arduino/HardwareSerial.cpp
+++ b/cores/arduino/HardwareSerial.cpp
@@ -56,7 +56,7 @@ void HardwareSerial::begin(unsigned long baud, uint8_t config)
   // leaving the data length selected as 8 bits
 
   // stop bit                       // stop bit = 1 - everything is zero, don't set anything
-  if  ((config >> 3) & (0x01 == 1)) // stop bit = 2
+  if  (((config >> 3) & 0x01) == 1) // stop bit = 2
     reg2config |= UART_CONTROL2_STOP_1_M;
 
   // turn on the receiver and transmitter, apply the parsed config