FEDEVEL
Platform forum

Modjo , 11-08-2018, 01:50 AM

Hi i would like to have more explanation about the utilities of and gate for USER BUTTON in 28 pins projest please ? Does this gate limit the "button rebound effect" ?

robertferanec , 11-08-2018, 04:42 AM

The purpose of the gate is clearly specify level of the signal which goes into the microcontroller - so there is always 0 or 1. I also like this gate approach, as you can for example see and measure the exact duration of the Button or Reset pulse. In more simple designs, you can use it without the gate, but the voltage will not be then clear 0 or 1 ... it will be a rising voltage - so you may need to double check the input pin parameters where you are connecting it to. Notice, the gate is "Schmitt-Trigger Action at All Inputs Makes the Circuit Tolerant for Slower Input Rise and Fall Time" which helps to make this circuit to work reliably.

Together with capacitor and resistor it helps to de-bounce the button signal.

Modjo , 11-08-2018, 06:35 AM

Very clear now