I am working to convert this following block of code into python so I can run it on my Raspberry Pi. In doing so I am trying to understand what each line does and was hoping someone could provide insight! Here is the code:
{
pinMode(pin, OUTPUT); // Step 1, part 1
digitalWrite(pin, HIGH); // Step 1, part 2
delay(1); // Step 2
pinMode(pin, INPUT); // Step 3 part 1
digitalWrite(pin, LOW); // Step 3, part 2
long time = micros(); // Step 4
while(digitalRead(pin)); // Step 5
time = micros() - time; // Step 6 & 7
return time;
}
The code was taken from a tutorial on learn.parallax. Step 5 is where I am trying to get further clarification. According to the website the purpose is to *"*Wait for the voltage to decay and pass below the Arduino’s 2.1 V threshold". It would make sense if the code said:
while(digitalRead(pin)== HIGH);
But it doesn't not so any clarification would be great. I have tested this code on my Arduino so I know that it works, just trying to understand why. Bonus points to anyone who can give me the python equivalent line using CircuitPython!
I am working to convert this following block of code into python so I can run it on my Raspberry Pi. In doing so I am trying to understand what each line does and was hoping someone could provide insight! Here is the code:
{
pinMode(pin, OUTPUT); // Step 1, part 1
digitalWrite(pin, HIGH); // Step 1, part 2
delay(1); // Step 2
pinMode(pin, INPUT); // Step 3 part 1
digitalWrite(pin, LOW); // Step 3, part 2
long time = micros(); // Step 4
while(digitalRead(pin)); // Step 5
time = micros() - time; // Step 6 & 7
return time;
}
The code was taken from a tutorial on [learn.parallax](http://https://learn.parallax.com/tutorials/robot/shield-bot/robotics-board-education-shield-arduino/chapter-6-light-sensitive-6). Step 5 is where I am trying to get further clarification. According to the website the purpose is to *"**Wait for the voltage to decay and pass below the Arduino’s 2.1 V threshold".* It would make sense if the code said:
while(digitalRead(pin)== HIGH);
But it doesn't not so any clarification would be great. I have tested this code on my Arduino so I know that it works, just trying to understand why. **Bonus points to anyone who can give me the python equivalent line using CircuitPython!** :)
In the line:
while(digitalRead(pin)); // Step 5
digitalRead returns the state of the pin as either HIGH or LOW. HIGH is defined as 1 and LOW is defined as 0.
When no comparison is specified (e.g. "==HIGH") the while statement continues as long as the return value is non-zero. In essence:
