單片機精華之利用內置定時器對外部按鍵進行計數

前面焊好的板子，按鍵按下10次以后，點亮led

上代碼：

#include

sbit led = P1^0;

unsigned int counter = 0;

void init(void)
{
led = 0;
TMOD = 0x06; // counter and 8-bit auto-reload
TH0 = 256 - 1;
TL0 = 256 - 1;
ET0 = 1;
EA = 1;
TR0 = 1;
}

void key_counter() interrupt 1
{
counter ++;
if(counter >= 3)
{
led = 1;
}
if(counter >=6)
{
counter = 0;
}

}

void main()
{
init();
while(1);
}

注意此時外部脈沖輸入的界限是P3.4口