51 MCU: Button control light on and off and flashing-EEWORLD

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Require:

The light is off when the power is on. Press the button once and the light will turn on. Press it again and the light will flash. Press it again and the light will flash faster.

Press again and the light turns off...

The cycle continues.

To do this, program as follows.

//----------------------------------------------

#include

unsigned char n = 0;

sbit key = P3^4;

sbit led = P0^0;

void delay()

{

unsigned int i, j;

for(i = 0; i < 100; i++) for(j = 0; j < 500; j++);

}

void readkey(void)

{

unsigned char i, j;

if(!key) {

for(i = 0; i < 10; i++)

for(j = 0; j < 120; j++); //delay debounce

if(!key) {

while(!key); //Wait for the key to be released

n++;

n %= 4; //n = 0~3

}

main()

{

while(1) {

switch(n) {

case 0: led = 1; readkey(); break; //turn off

case 1: led = 0; readkey(); break; //长亮

case 2: delay(); readkey(); //slow flashing

case 3: delay(); readkey(); led = ~led; //fast flashing

}

//----------------------------------------------

This program has been verified in practice and can meet the requirements of the topic.

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