8253产生方波不成功

[gao11zhang]

电路图如上，程序在下面，想要产生方波，但是却没有，请帮忙看看怎么回事

#include "reg52.h"
#include <intrins.h>
#include <absacc.h>

#define uint unsigned int
#define uchar unsigned char

/*操作地址0xffff; t0地址0x3fff; t1地址0x7fff; t2地址0xbfff;*/
sbit led1=P1^3; //指示灯1
sbit led2=P1^4; //指示灯2
sbit bell=P1^1;
unsigned char xdata *p; //p用来做地址访问指针
#define COM8254 XBYTE[0xffff]
#define T08254 XBYTE[0x3fff]
#define T18254 XBYTE[0x7fff]
#define T28254 XBYTE[0xbfff]


void delay(uint n)
{
uint i,j;
for(i=0;i<100;i++)
{
for(j=0;j<n;j++)
{}
}

}


void main()
{bell=1;
//P1=0x00;
COM8254=0x35;
T08254=0xf4;
T08254=0x01;

while(1)
{

}
}