求原因？AVR16捕获调试的原因。TIMER1输入捕获频率计例程
本帖最后由 SCREA 于 2014-2-20 16:35 编辑求怎么回事，第1、3、4个频率正常，唯独频率从1K到5K左右不正常
//-----------------------------------------------------------------
//名称: 用TIMER1输入捕获功能设计的频率计
//-----------------------------------------------------------------
//说明: 本例运行时,切换不同的频率输入,然后按下K1按键,数码管上将
// 显示当前频率值.两次捕获的时间差值即为当前输入频率的周期,
// 周期倒数即可得到当前频率.
//
//-----------------------------------------------------------------
#defineF_CPU1000000UL //1M晶振
#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>
#define INT8U unsigned char
#define INT16Uunsigned int
//共阴数码管0-9的数字编码,最后一位为黑屏
const INT8U SEG_CODE[] =
{0x3F,0x06,0x5B,0x4F,0x66,0x6D,0x7D,0x07,0x7F,0x6F,0x00};
//分解后的待显示数位
INT8U Display_Buffer[] = {0,0,0,0};
//连续两次捕获计数变量
INT16U CAPi=0,CAPj=0;
volatile INT16U Buffer = {0};
volatileunsigned long SS = 0;
volatile INT8U j=0;
//-----------------------------------------------------------------
// 数码管显示频率
//-----------------------------------------------------------------
void Show_FRQ_ON_DSY()
{
INT8U i=0;
for( i =0;i<4;i++)
{
PORTB = ~_BV(i);
PORTA = SEG_CODE[ Display_Buffer ];
if(i==0)PORTA |= 0x80;
_delay_ms(2);
}
}
//------------------------------------------------------------------
// 主程序
//------------------------------------------------------------------
int main()
{
INT8U LastKey = 0xff;
DDRA = 0xff;
DDRB = 0xff;
DDRC = 0x00; PORTC = 0xff;
DDRD = 0x00; PORTD = 0xff;
TCCR1B = _BV(ICNC1) | _BV(ICES1);//输入捕获噪声音消除，ICP上升沿触发捕获，分频系数1（1MHz，1us触发一次）
sei();
while(1)
{
if( LastKey != PINC)
{
TIMSK = _BV(TICIE1);
TCCR1B |= 0x01;
LastKey = PINC;
}
Show_FRQ_ON_DSY();
}
}
//------------------------------------------------------------------
// T1输入捕获中断子程序
//------------------------------------------------------------------
ISR (TIMER1_CAPT_vect)
{
INT8U i,k;
INT16U temp=0;
if(CAPi == 0 )CAPi = ICR1;
else
{
CAPj = ICR1 - CAPi;
Buffer =1000000UL/ CAPj;
j++;
if(j==6)
{
j=0;
TIMSK = 0x00;
TCCR1B &= 0xf8;
for(k=0;k<6;k++) //采样6次，取中间4个值求平均
{
for(i=0;i<5-k;i++)
{
if(Buffer>Buffer)
{
temp = Buffer;
Buffer = Buffer;
Buffer = temp;
}
}
}
SS = (Buffer + Buffer + Buffer+ Buffer )/4;
for(i=3;i!= 0xff;i--)
{
Display_Buffer = SS%10;
SS /= 10;
}
}
TCNT1 = CAPi = CAPj = 0;
}
}
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