Zeroplus Arduino starter kit with Logic Analyzer Manual page 120

CODE EXPLANATION
• setInterrupts() Enables interrupts on the pins connected to
the buttons
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• ISR(PCINT0_vect) This is where we tell the microprocessor what
actions to perform when an interrupt is called. It is best to
keep it short so that the processor can quickly return to its
normal state.
• eliminateBounce() The mechanical contacts are not perfect.
They are unstable. Therefore, it is necessary to remove the
rebounds in order to get a clear Low when a button is pressed.
.