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Encoded16To4Buttons.ino
Encoded16To4Buttons.ino
 
 
Makefile
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README.md
README.md
 
 
breadboard_16to4_74ls148_small.jpg
breadboard_16to4_74ls148_small.jpg
 
 

README.md

Binary Encoded 16-to-4 Buttons

The Encoded16To4Buttons.ino is a sample code for EncodedButtonConfig (which is a generalization of Encoded4To2ButtonConfig and Encoded8To3ButtonConfig) to show how it can be used to handle 15 buttons with 4 pins. These classes are described in detail in BinaryEncoding.

This program demonstrates 16-to-4 encoding to support 15 buttons using 4 pins using:

  • 2 x 74LS148 8-line to 3-line priority encoder
  • 1 x 74LS08 quad 2-input AND gate
  • 1 x SparkFun Pro Micro (clone)
  • 4 x push buttons

A partial schematic is:

Schematic 74LS148

Here is the breadboard that implements this circuit, but with only pins 1, 7, 8, and 15 for demonstration purposes:

Breadboard 74LS148

Sample Output

The sample output looks where each button was Pressed then Released, then was Pressed/Released quickly to generate a Clicked event. Blank lines were added for readability:

handleEvent(): virtualPin: 1; eventType: Pressed; buttonState: 0
handleEvent(): virtualPin: 1; eventType: Released; buttonState: 1

handleEvent(): virtualPin: 7; eventType: Pressed; buttonState: 0
handleEvent(): virtualPin: 7; eventType: Released; buttonState: 1

handleEvent(): virtualPin: 8; eventType: Pressed; buttonState: 0
handleEvent(): virtualPin: 8; eventType: Released; buttonState: 1

handleEvent(): virtualPin: 15; eventType: Pressed; buttonState: 0
handleEvent(): virtualPin: 15; eventType: Released; buttonState: 1

handleEvent(): virtualPin: 1; eventType: Pressed; buttonState: 0
handleEvent(): virtualPin: 1; eventType: Clicked; buttonState: 1
handleEvent(): virtualPin: 1; eventType: Released; buttonState: 1

handleEvent(): virtualPin: 7; eventType: Pressed; buttonState: 0
handleEvent(): virtualPin: 7; eventType: Clicked; buttonState: 1
handleEvent(): virtualPin: 7; eventType: Released; buttonState: 1

handleEvent(): virtualPin: 8; eventType: Pressed; buttonState: 0
handleEvent(): virtualPin: 8; eventType: Clicked; buttonState: 1
handleEvent(): virtualPin: 8; eventType: Released; buttonState: 1

handleEvent(): virtualPin: 15; eventType: Pressed; buttonState: 0
handleEvent(): virtualPin: 15; eventType: Clicked; buttonState: 1
handleEvent(): virtualPin: 15; eventType: Released; buttonState: 1