Single Chip Microcomputer Lesson 6th: Principle of independent button Detection

Connect the 8th pin of jp5 to the P1 ^ 0 of the microcontroller, and then connect P1 ^ 0 with the positive pin of the light-emitting diode. (when the light-emitting diode is added to a high level, the light-emitting diode will be on, because each IO port is a high level by default when the single chip microcomputer is powered on, after the wires are connected, the light-emitting diode will light up ). When we press K1, the Light Emitting Diode goes off, the button is released, and the light emitting diode lights up again. Because when you press the button, the TTL circuit only has two levels, showing the relationship between the "line and", and again detecting the level of P1 ^ 0 pin, you will find that it is already low. Because the high level and the upper level are equal to the lower level.

Single Chip Microcomputer Lesson 6th: Principle of independent button Detection