部落客福利:100G+電子設計學習資源包!
http://mp.weixin.qq.com/mp/homepage?__biz=MzU3OTczMzk5Mg==&hid=7&sn=ad5d5d0f15df84f4a92ebf72f88d4ee8&scene=18#wechat_redirect --------------------------------------------------------------------------------------------------------------------------
頻率測量方法:
- 測頻法:測試限定時間内檢測脈沖的個數(1s)
- 測周法:采樣N個脈沖所使用的時間
測頻法實驗:
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設計要求:
通過測頻法測出時鐘發生器的頻率并顯示在顯示屏上
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實作過程:
通過DCLOCK時鐘發生器産生時鐘頻率,如下圖所示,一秒鐘産生233個頻率
T0接收時鐘發生器産生的脈沖,使用count變量計數,定時器T1完成1s後關閉中斷,并将此時的count顯示出來
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元件清單:
- AT89C51
- 7SEG-MPX8-CC-BLUE
- DCLOCK(在電壓探針清單中)
#include <reg52.h>
typedef unsigned int uint;
typedef unsigned char uchar;
uchar code number[] =
{
0xFC, 0x60, 0xDA, 0xF2, 0x66, 0xB6, 0xBE, 0xE0, 0xFE, 0xF6, 0xEE, 0x3E, 0x9C, 0x7A, 0x9E, 0x8E
};
uchar code address[] =
{
0xFE, 0xFD, 0xFB, 0xF7, 0xEF, 0xDF, 0xBF, 0x7F
};
uint count = 0, time = 0, temp; //一定要用int類型,char類型隻有8位,計數隻到255
bit flag = 0;
void Delay(uchar m)
{
while(--m);
}
int main()
{
uchar i;
EA = 1;
ET0 = 1;
ET1 = 1;
TMOD = 0x16; //定時器1為方式1,計數器0為方式2,T0選擇C/T=1,計數器方式,脈沖由外部提供
TH0 = 0xff;
TL0 = 0xff;
TR0 = 1;
TH1 = (65536 - 50000) / 256;
TL1 = (65536 - 50000) % 256;
TR1 = 1;
while(1)
{
if (flag == 1)
{
temp = count;
for (i = 0; i < 8; ++i)
{
P2 = address[i];
P1 = number[temp % 10];
temp = temp / 10;
Delay(500);
}
}
}
}
void Count0()interrupt 1
{
++count;
}
void Time1()interrupt 3
{
TH1 = (65536 - 50000) / 256;
TL1 = (65536 - 50000) % 256;
++time;
if (time == 20)
{
EA = 0;
flag = 1;
}
}