doc: update README for Atom2.5

Author: zlj-zz

README.md

@@ -1,15 +1,18 @@
 # This is Python API for myCobot
 
-If you want to install it separately.
+This is a python API for serial communication with mycobot and controlling it.
+
+<!--![](./f3-min2.jpg)-->
 
 ## Installation
 
 **Notes**:
 
 <!-- This is the mycobot Python API package designed by Zhang Lijun([lijun.zhang@elephantrobotics.com]()) -->
 
-> Make sure that `Atom` is flashed into the top Atom, `Transponder` is flashed into the base Basic <br>
+> Make sure that `Atom` is flashed into the top Atom, `Transponder` is flashed into the base Basic. <br>
 > The firmware `Atom` and `Transponder` download address: [https://github.com/elephantrobotics/myCobot/tree/main/Software](https://github.com/elephantrobotics/myCobot/tree/main/Software)<br>
+> You also can use myStudio to flash them, myStudio address: [https://github.com/elephantrobotics/myStudio/releases](https://github.com/elephantrobotics/myStudio/releases)
 
 ### Pip
 
@@ -19,6 +22,7 @@ pip install pymycobot --upgrade --user
 
 **Notes:**
 
+> If you want to use Gripper and IO, you should update your Atom to 2.5<br>
 > Now only the version is `Atom2.4` or later is supported. If you use an earlier version, please install `pymycobot 1.0.7`.
 
 ```bash
@@ -36,8 +40,10 @@ python2 setup.py install
 python3 setup.py install
 ```
 
-**_`test/test.py` is a test file, you can find out which interfaces pymycobot provides in `pymycobot/README.md`._**
-
 ## Usage:
 
+The `tests` directory stores some test case files.
+
+You can find out which interfaces pymycobot provides in `pymycobot/README.md`.
+
 Please go to [here](./pymycobot/README.md).

f3-min2.jpg

@@ -159,11 +159,11 @@ from pymycobot.mycobot import MyCobot
 
 - **Description**
 
-  Get the Coords from robot arm.
+  Get the Coords from robot arm, coordinate system based on base.
 
 - **Returns**
 
-  `list`: A float list of coord.
+  `list`: A float list of coord - `[x, y, z, rx, ry, rz]`
 
 ### send_coord()
 
@@ -201,7 +201,7 @@ from pymycobot.mycobot import MyCobot
   coords: a list of coords value(`List[float]`)
 
   speed: (`int`)
-  
+
   mode: (`int`): `0` - angluar, `1` - linear
 
 - **Example**