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#include <reg52.h>
sbit ALE = P3^3;
sbit OE = P3^4;
sbit EOC = P3^5;
sbit STA = P3^6;
sbit CLK = P3^7;
unsigned int num; //AD轉換后的數(shù)字量
char ch; //通道號碼
// 延時函數(shù)
void delay(unsigned int z)
{
unsigned int x, y;
for(x = z; x > 0; x--) for(y = 110; y > 0; y--) CLK = ~CLK;
}
// 數(shù)碼管顯示函數(shù)
void display(void)
{
char code table[] = { //共陰段碼
0x3f, 0x06, 0x5b, 0x4f, 0x66, 0x6d, 0x7d, 0x07, //0~7
0x7f, 0x6f, 0x77, 0x7c, 0x39, 0x5e, 0x79, 0x71}; //8~F
P0 = 0; P2 = 0xf7; P0 = table[ch]; delay(2);//通道號碼
P0 = 0; P2 = 0xfb; P0 = table[num / 100] + 128; delay(2);//百位加上小數(shù)點
P0 = 0; P2 = 0xfd; P0 = table[num % 100 / 10]; delay(2);//十位
P0 = 0; P2 = 0xfe; P0 = table[num % 10]; delay(2);//個位
P0 = 0; //關閉顯示器
}
// 轉換函數(shù)
void main(void)
{
while(1) { //無窮循環(huán)
ch = P2 / 32; //取來通道號碼
P3 = ch + 0xf8; //送給ADC0808
ALE = 1; ALE = 0; //地址鎖存
STA = 1; STA = 0; //開始轉換,稍候,才可讀EOC
display(); //顯示,既做延時,又輸出CLK
while(EOC == 0) display(); //等待轉換結束
num = P1; //取出轉換結果
num = num * 100 / 51; //比例變換:255 --> 500
}}
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