求助各位大哥，急

只看该作者 · 2010-5-25 09:59

小弟最近接了一个项目，用lpc2132作控制器，采集信号，用8253进行累加计数，我用2132的P1_16-19，p1_21-24作为数据口d0-d7，对8253进行读写。我现在用脉冲发生器给8253发确定脉冲，比如10个脉冲，可是我读出来的都是大于10的，给的脉冲越多，误差就越大，小弟苦思冥想N天，就是不得其解，忘各位大哥给看看，出了什么问题

只看该作者 · 2010-5-25 10:02

void write_8253_cnt(uint8 chose_8253,uint8 dat_8253,uint8 a1a0)
{

if(!chose_8253)
Output(p0_25,0);//片选8253(1)cs
else
Output(p0_26,0);//片选8253(2)cs
//Output(p0_30,0);//选中wr
switch(a1a0)
{
case 0:
Output(p0_28,0);//A1
Output(p0_27,0);//A0
break;
case 1:
Output(p0_28,0);//A1
Output(p0_27,1);//A0
break;
case 2:
Output(p0_28,1);//A1
Output(p0_27,0);//A0
break;
case 3:
Output(p0_28,1);//A1
Output(p0_27,1);//A0
break;
}

write_8253_dat(dat_8253);

Output(p0_30,0);//选中wr
DelayNS(10);
Output(p0_30,1);//放弃wr
if(!chose_8253)
Output(25,1);//放弃8253(1)cs
else
Output(26,1);//放弃8253(2)cs

}
uint8 read_8253_dat(uint8 a1a0,uint8 chose_8253)
{

uint8 read_i=0;

if(!chose_8253)
Output(p0_25,0);//选中cs1
else
Output(p0_26,0);//选中cs2

//Output(p0_29,0);//选中rd

switch(a1a0)
{
case 0:
Output(p0_28,0);//A1
Output(p0_27,0);//A0

break;
case 1:
Output(p0_28,0);//A1
Output(p0_27,1);//A0

break;
case 2:
Output(p0_28,1);//A1
Output(p0_27,0);//A0

break;
}
DelayNS(1);
Output(p0_29,0);//选中rd

DelayNS(1);

read_i=(Read_pin(p1_24,p1_24)&0x01)<<7;
read_i=read_i|(Read_pin(p1_23,p1_23)&0x01)<<6;
read_i=read_i|(Read_pin(p1_22,p1_22)&0x01)<<5;
read_i=read_i|(Read_pin(p1_21,p1_21)&0x01)<<4;
read_i=read_i|(Read_pin(p1_19,p1_19)&0x01)<<3;
read_i=read_i|(Read_pin(p1_18,p1_18)&0x01)<<2;
read_i=read_i|(Read_pin(p1_17,p1_17)&0x01)<<1;
read_i=read_i|(Read_pin(p1_16,p1_16)&0x01);

Output(p0_29,1);//放弃rd

if(!chose_8253)
Output(p0_25,1);//放弃cs1
else
Output(p0_26,1);//放弃cs2

//Output(p0_29,1);//放弃rd
return(read_i);

}
这是我的读写函数

求助各位大哥，急

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