Edge Detection with Timeout Setting

This section describes how to use the demo program to verify edge detection works correctly on VisionFive 2 or VisionFive 2 Lite with and without timeout settings.

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 to the 40-pin GPIO Header:


Button	40-Pin GPIO Header
Button	Pin Number	Pin Name
Pin ④	37	GPIO60
Pin ③	39	GND

Table 1. 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_waiting_time.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_waiting_time.py
```
Alternatively, you can also run the following command.
```
sudo python3  edge_detection_with_waiting_time.py
```
The terminal displays the following:
```
# python3 edge_detection_with_waiting_time.py 
*-----------------------Case 1-----------------------------------------------------*
Note: don't press the key on pin 37 once within 5 seconds !!!
```
Case 1: 5-second timeout. The code waits 5 seconds for you to press the button. If you do not press the button, no edge detection.
```
Edge hasn't been detected within 5 seconds  while setting 5 seconds to timeout.
The return value of GPIO.event_detected(37) within 5 seconds: False

*-----------------------Case 2-----------------------------------------------------------------------*
Please press the key on pin 37 once at any time !!!
```
Case 2: Infinite wait. The code waits forever until you press the button. If you press the button at any time, edge is detected successfully.
```
Edge has detected while setting -1 to timeout,
timeout -1 means waiting until edge is detected.

The return value (True) of GPIO.event_detected(37) should be True.
The return value (False) of GPIO.event_detected(37) should be False, because of the secondly reading.
```
Note: For details about the source code, see edge_detection_with_waiting_time.py Source Code.
(Optional) Exit the Python3 Virtual Environment.
```
deactivate
```