Improve content

- Rewrite external module section
- fix spi illustration to show c1 and c2
- fix code snippets for ext. modules.

Author: Hannes7eicher

content/micropython-course/course/01.introduction-python/02.intro-to-micropython.md

@@ -146,39 +146,64 @@ For example, to use a module for a specific sensor, we need to install it **exte
 
 ### Install External Modules
 
-To install an external module, we are going to use something called `mip`. With `mip`, we can install a module on the board directly, by connecting to Wi-Fi and downloading the module directly to the board. So how do we do this?
+To install an external module, we are going to use a package manager called `mip`. With `mip`, we can install a module on the board by connecting to Wi-Fi® and downloading the module directly to the board. So how do we do this?
 
-Below is a script that first connects to Wi-Fi®, and then downloads a specific module. In this case, we will provide a URL to a file stored on GitHub (the raw file). In this case, we will install the `lis3dh` module, which will be used later on in this course.
+To download external modules from the internet we first a foremost need a working internet connection. To connect to your local Wi-Fi you can upload the following script to your `boot.py` file. Why `boot.py`? 
 
-Please note that you need to add your own Wi-Fi® network and password in the `WIFI_NETWORK` and `WIFI_PASSWORD` fields.
+Because we want to make sure our board connects to the internet as soon as it boots up.
+
+***Please note that you need to add your own Wi-Fi network and password in the `WIFI_NETWORK` and `WIFI_PASSWORD` fields.***
+
+![Wi-Fi script inside boot.py](./assets/boot.png)
+
+**Connect to Wi-Fi**
 
 ```python
 """
-This script first connects to Wi-Fi,
-then installs the module specified
-in the URL variable.
+This script connects to Wi-Fi
 """
 
 import network
-import mip
 
 WIFI_NETWORK='YOUR_NETWORK_NAME'
 WIFI_PASSWORD='YOUR_NETWORK_PASSWORD'
 
-# add the URL of the module you want to install
-URL = "https://raw.githubusercontent.com/tinypico/tinypico-micropython/master/lis3dh%20library/lis3dh.py"
-
 wlan = network.WLAN(network.STA_IF)
 wlan.active(True)
 wlan.connect(WIFI_NETWORK, WIFI_PASSWORD)
 
 print()
 print("Connected to ",WIFI_NETWORK)
+```
+ Press run and you should see `Connected to <your Wi-Fi>` being printed inside the REPL.
+
+ ![Successful connection](./assets/wifiConnected.png)
+
+ Next, you need to run a script that installs the external module from a specific url. Place the following script inside `main.py` and press run.
+
+![Module installation script inside main.py](./assets/main.png)
 
-mip.install(URL)
+**Install external module**
+```python
+'''
+This script installs external modules using mip
+'''
+
+import mip
+mip.install("https://raw.githubusercontent.com/tinypico/tinypico-micropython/master/lis3dh%20library/lis3dh.py")
 ```
 
-Once you run the script successfully, you will have installed the module on your board.
+Press run and you should see the following inside the REPL:
+
+![Successful download](./assets/download.png)
+
+In this case, we will provide a URL to a file stored on GitHub (the raw file). The script installs the `lis3dh` module, which will be used later on in this course.
+
+You can verify that the module was installed correctly by pressing `Files` and checking inside the `lib` folder. You should see a file called `lis3dh.py` inside.
+
+![Installed module](./assets/libFolderIn.png)
+
+When asked later in the course to install external modules simply paste the provided script into `main.py` and press run.
 
 ### Removing Modules
 
@@ -215,9 +240,9 @@ OSError: -202
 
 Some things to check are:
 - Did you enter your network credentials properly?
-- Did you already connect to Wi-Fi®?
+- Did you already connect to Wi-Fi?
 
-If the error persist, you can try to "soft-reset" the board, by clicking the **"Reset"** button, and run the script again.
+If the error persists, you can try to "soft-reset" the board, by clicking the **"Reset"** button, and run the script again.
 
 ![](assets/reset.png)
 

content/micropython-course/course/01.introduction-python/assets/boot.png

@@ -287,6 +287,7 @@ This example demonstrates how to use an [OLED](https://store.arduino.cc/products
 This module is not part of the MicroPython installation, and needs to be installed via the following command:
 
 ```python
+import mip
 mip.install("https://raw.githubusercontent.com/micropython/micropython-lib/master/micropython/drivers/display/ssd1306/ssd1306.py")
 ```
 
@@ -386,6 +387,7 @@ This example shows how to use a [Grove Accelerometer](https://store.arduino.cc/p
 This module is not part of the MicroPython installation, and needs to be installed via the following command:
 
 ```python
+import mip
 mip.install("https://raw.githubusercontent.com/tinypico/tinypico-micropython/master/lis3dh%20library/lis3dh.py")
 ```
 
@@ -502,6 +504,7 @@ This example shows how to use a [Grove 4-digit display](https://store.arduino.cc
 This module is not part of the MicroPython installation, and needs to be installed via the following command:
 
 ```python
+import mip
 mip.install("https://raw.githubusercontent.com/mcauser/micropython-tm1637/master/tm1637.py")
 ```