Update README.md

Author: shennongmin

readme.md

@@ -1,4 +1,5 @@
 # Nextion Library for Arduino 
+
 Nextion Arduino library provides an easy-to-use way to manipulate Nextion serial displays. 
 Users can use the libarry freely, either in commerical projects or open-source prjects,  without any additional condiitons. 
 
@@ -18,28 +19,16 @@ You can clone it by:
 
     git clone https://github.com/itead/ITEADLIB_Arduino_Nextion
 
-
 # Hareware requirement 
 
   - RAM: not less than 2KBytes
-  - Serial: one serial (HardwareSerial or SoftwareSerial) at least 
-
-Suppported Mainboards: Arduino family and it's derivatives.
-We test this library with Iteaduino UNO and Iteaduino Mega2560.
-
-
-# Using SoftwareSerial
-
-If you want to use SoftwareSerial to communicate with Nextion display, you need to modify
-the line in file `hmi.h`: 
-
-    //#define HMI_SOFTWARE_SERIAL
+  - Serial: two serial (communication and debug)
 
-After modification, it should be:
+# Suppported Mainboards:
 
-    #define HMI_SOFTWARE_SERIAL
+  - Iteaduino MEGA2560
+  - Arduino MEGA2560
 
-Nextion library only requires an uart for hardware connection. All communications are done via uart.   
 
 -------------------------------------------------------------------------------