Update README.md

Author: rossmann-engineering

README.md

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 # EasyModbusTCP.NET
+
+Modbus TCP, Modbus UDP and Modbus RTU client/server library for .NET
+
+For JAVA-Version see: https://sourceforge.net/projects/easymodbustcp-udp-java/
+
+Now available: Modbus RTU Slave for ATMEL ATMEGA microcontrollers
+
+See Also CRC-Checking Tool for RTU Frames: http://easymodbustcp.net/crc-calculation 
+
+Supports Function Codes:
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+- Read Coils (FC1)
+- Read Discrete Inputs (FC2)
+- Read Holding Registers (FC3)
+- Read Input Registers (FC4)
+- Write Single Coil (FC5)
+- Write Single Register (FC6)
+- Write Multiple Coils (FC15)
+- Write Multiple Registers (FC16)
+
+
 Modbus TCP, Modbus UDP and Modbus RTU client/server library
 
 Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)