求大神帮忙算一下我这个C51定时的周期时间

#include <reg51.h>
sbit P11=P1^1;
sbit P33=P3^3;
int i; int n;
void main(void)
{
P1=0x02; P3=0x08;
TMOD = 0x10; TH1 = 0x4C; TL1 = 0x00;
EA = 1; ET1 = 1; TR1 = 1;
while(1);
}
void Timer1(void) interrupt 3
{ TH1 = 0x4C; TL1 = 0x00;
i++; n++;
if (n==2000)
{
n=0; P11=1;
}
while(i==1000)
{
i=0;
if(P33==1)
{
P11=~P11;
}
}
if(P33==0)
{
if(n<=500) P11=1;
else P11=0;
}
}