Debounced Buttons Breakout Board

If you need a precision interface between a user and your circuit, this is the board for you. The Debounced Button Breakout Board provides three buttons that are debounced through a hardware RC network. It’s the same circuit used for on the Manual Serial Trainer and I2C and SPI Education Shield. That means you can add three crisp digital inputs to your board without having to modify your code to track milliseconds of pause time to make sure the button has settled. These provide zero bounce — GND to V_CC and back again — very crisp, very clean.

This circuit is based on the classic Jack Ganssle solution and is perfect for triggering interrupts. A network of two resistors and a capacitor feed the input of a schmitt-trigger inverter and the inverter generates the signal instead of the button mechanism. Because the debounced buttons are now filtered in hardware, you don’t have to include any potentially blocking code to do that filtering instead. Clean signals and clean code!

But don’t take my word for it, here’s what Mr. Oscilloscope has to say about it!

Here’s the before…

Here’s the after…

The RC network designed for the tactile buttons is calculated to work with a 5V V_CC. All three buttons are brought out to the pin header for easy connection to your project.