Interrupts are an efficient way for a program to be able to respond immediately to a specific event. In the previous article I explained the basics of using interrupts in RPi.GPIO and gave an example of a simple “wait for an event” interrupt program.
In this second article I will introduce “threaded callback” which opens up a lot of new possibilities.
So What are we going to do now?
We’ll keep most of what we did before and add another button and an event detect threaded callback that runs when the new button is pressed, even though we are still waiting for the first button to be pressed.
But this time, the new button will connect GPIO port 24 to 3.3V (3V3) when pressed. This will allow us to demonstrate a rising edge detection. So we’ll be setting up port 24 with the built in pulldown resistor enabled.
Later on we’ll have to modify the code to cope with ‘button bounce’, but we won’t say any more about that just yet.
Each Friday is PiDay here at Adafruit, be sure to check out our posts, tutorials and new Raspberry Pi related products. Have you tried the new “Adafruit Raspberry Pi Educational Linux Distro” ? It’s our tweaked distribution for teaching electronics using the Raspberry Pi. But wait, there’s more! Try our new Raspberry Pi WebIDE! The easiest way to learn programming on a Raspberry Pi.
We now have Raspberry Pi Model B with 512MB RAM in stock and shipping now!
Have an amazing project to share? Join the SHOW-AND-TELL every Wednesday night at 7:30pm ET on Google+ Hangouts.
Join us every Wednesday night at 8pm ET for Ask an Engineer!
Learn resistor values with Mho’s Resistance or get the best electronics calculator for engineers “Circuit Playground” – Adafruit’s Apps!
Maker Business — Raspberry Pi and CoderDojo Join Forces
Wearables — Gold glow
Electronics — Linear Love
Biohacking — Nike’s Unlimited Stadium Will Put Your Best Foot Forward
No comments yet.
Sorry, the comment form is closed at this time.