added md

docs/tcp_cmd.md

@@ -0,0 +1,18 @@
+# TCP Command Interface
+This is the documentation of the TCP Command Interface task
+
+## Table of contents
+- [Table of contents](#table-of-contents)
+- [Initialization](#initialization)
+- [Usage](#usage)
+
+## Initialization
+The TCP Command Interface task is initialized in the main function.
+```c
+// Initialize Modbus task
+tcp_cmd_init();
+```
+## Usage
+
+![putty](./img/Putty.png)
+![IPv4](./img/IPv4_computer.png)