程序如下，調(diào)試時出現(xiàn)錯誤。求高手指導(dǎo)。。幫忙找出錯誤~~~

#include<reg52.h>
#define uchar unsigned char
#define uint unsigned int
sbit trig=P1^0;
sbit echo=P3^2;
sbit test=P1^2;
uchar distance,time,outH,outL;
void delay_20us();
void delay(uint);
void nint();
void count();

void main()
{
while(1)
{
nint();
delay(100);
trig=1;
delay_20us();
trig=0;
while(!echo)
TR0=0;
while(echo)
TR0=1;
delay(1000);
count();
}
}

void init() //初始化函數(shù)
{
trig=0;
echo=0;
test=1;
//外部中斷
EA=1;
EX0=1;
IT0=0;
//T0中斷
TMOD=0X01;
TH0=0;
TL0=0;
ET0=1;
TR0=0;
}

void INT0_time() interrupt 0 //外部0中斷函數(shù)
{
TR0=1;
while(!echo)
TR0=0;
outH=TH0;
outL=TL0;
}

void T0_time() interrupt 1 //定時器中斷函數(shù)
{
TH0=0;
TL0=0;
}

void count()
{
time=outH*256+outL;
distance=(time*17)/1000;
if(distance<20&&distance!=0)
test=0;
}

void delay_20us()
{
uint i;
for(i=0;i<100;i++);
}

void delay(uint z)
{
uint x,y;
for(x=z;x>0;x--)
for(y=110;y>0;y--);