Use a Button to Control LED Dot Matrix

This section describes how to use VisionFive 2 or VisionFive 2 Lite's GPIO pins to develop an LED dot matrix display after pressing a button.

Hardware Setup

Connect pin ① and pin ② of the button to the breadboard first, and then connect pin ③ and pin ④ to VisionFive 2 or VisionFive 2 Lite. The following table and figure describe how to connect the button and MAX7219 to the 40-pin GPIO Header:

Figure 1. Connect Button and MAX7219 to the 40-Pin Header

Table 1. Connect Button to 40-Pin Header
Button	40-Pin GPIO Header
Button	Pin Number	Pin Name
Pin ④	37	GPIO60
Pin ③	39	GND

Table 2. Connect MAX7219 to 40-Pin Header
MAX7219	40-Pin GPIO Header
MAX7219	Pin Number	Pin Name
VCC	2	5V Power
GND	34	GND
DIN	40	GPIO44
CS	38	GPIO61
CLK	36	GPIO36

Run Demo Code

Perform the following steps on Debian of VisionFive 2 or VisionFive 2 Lite.

Locate the directory where the test code, edge_detection_with_LED_Matrix.py, exists.
1. Source into the Python3 Virtual Environment.
```
source ./myvenv/bin/activate
```
2. Install the dependency.
```
python3 -m pip install pillow
```
3. Get the directory where VisionFive.gpio exists.
```
python3 -m pip show VisionFive.gpio
```
  Note: The output depends on how the application is installed.
4. Enter the VisionFive.gpio directory.
```
cd <VisionFive.gpio directory>
```
5. Enter the sample-code directory.
```
cd ./VisionFive/sample-code/
```
Under the sample-code directory, execute the following command to run the demo code.
```
sudo python  edge_detection_with_LED_Matrix.py
```
Alternatively, you can also run the following command.
```
sudo python3  edge_detection_with_LED_Matrix.py
```
The terminal displays the following:
```
# python3 edge_detection_with_LED_Matrix.py 
*------------------------------------------------------*
Please press the key on pin 37 to launch !!!
```
Press the button according to the prompt, and the LED matrix module counts down from 5 to 1 and then displays the S logo.
Figure 2. Countdown and StarFive Logo

Note: For details about the source code, see edge_detection_with_LED_Matrix.py Source Code.
(Optional) Exit the Python3 Virtual Environment.
```
deactivate
```