// 資訊四A 方立翔 9879001 2012/12/04 作業一
#include <reg51.h>
sbit P1_4 = P1^4; // INPUT
sbit P3_5 = P3^5; // BUZZER
sbit P3_3 = P3^3; // PB_SW
int t = 64820; // So=784Hz, 65536-716=64820
void delay(int);
main()
{
unsigned char i;
int j;
IE = 0x84;
TMOD = 0x01;
TCON = 0x00;
P2 = 0xff;
while(1)
{
i = 0x00;
if(P1_4 == 0)
{
for (j = 1; j <= 6; j++)
{
P2 = ~i;
delay(30); // 20ms *40 = 800ms = 0.8s
i = ~i;
}
P2 = 0xff;
}
}
}
void delay(int count) // delay 20ms
{
int m, n;
for(m = 1; m <= count; m++)
{
for(n = 1; n <= 2000; n++)
{
;
}
}
}
void EX1_int(void) interrupt 2
{
int j;
for(j = 1; j <= 250; j++)
{
P3_5 = 1;
TH0 = t /256;
TL0 = t % 256;
TR0 = 1;
while(TF0 == 0)
{
;
}
TF0 = 0;
P3_5 = 0;
TH0 = t /256;
TL0 = t % 256;
TR0 = 1;
while(TF0 == 0)
{
;
}
TF0 = 0;
}
}
