update

Author: lxw119

README.md

@@ -2,11 +2,41 @@
 
 > dotnet version: 5.0.103
 
+##download
+
 You can download the `.dll` at [Release](https://github.com/elephantrobotics/Mycobot.csharp/releases)
 
-And import it to you Project.
+###**notice:**<br>
+if you project **target frame** is **.net core**,download **net core/Mycobot.csharp.dll**,if is **.net framework**,download **net framework/Mycobot.csharp.dll**)
+
+###how to check target frame
+
+![pic](res/frame.gif)
+
+##use
+
+###import
+
+1、import **Mycobot.csharp.dll** to you Project.<br>
+2、add system.io.ports to ***.csproj(*** is your project name,this file is in your project directory),like this:<br>
+**frame: .net core**<br>
+![pic](res/port_1.jpg)<br>
+**frame: .net framework**<br>
+![pic](res/port_2.jpg)
+
+
+###problem
+
+when use you will have some prolem:<br> 
+1、probelm: System.Runtime, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies...<br>
+solve:update your sdk(if .net core,update to **5.0** and choose,if .net framework update to **4.0** and choose **4.7.2**),like this:<br>
+![pic](res/update.gif)
+<br>
+2、probelm:System.IO.FileNotFoundException:“Could not load file or assembly 'System.IO.Ports, Version=6.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'. <br>
+solve:look use-->2
+ 
 
-```c#
+###API
 /// arm power on
 public void PowerOn()