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这是一个温度显示程序，用的是DS18B20测温度，有几个问题我想问问大家。<br />1、四个数组中的后三个数组都表示是什么意思？尤其是最后一个，怎么还有一样的数值。<br />2、小数位的值是怎么来的？<br />我是个菜鸟，想半天也没想明白。<br /><br />#include "avr/io.h" //头文件<br />#include "avr/delay.h" //头文件<br /><br />#define BEEP PD7 //蜂鸣器<br />#define DQ PD3 //ds18b20的DQ<br />#define FREQ 8 //芯片工作频率<br /><br />unsigned char presence,flash=0;<br /><br />unsigned char LEDData[ ] = {0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,<br />0x80,0x90,0xff};<br /> <br />unsigned char temp_data[2] = {0x00,0x00};<br /><br />unsigned char display[5] = {0x00,0x00,0x00,0x00,0x00};<br /><br />unsigned char ditab[16] = {0x00,0x01,0x01,0x02,0x03,0x03,0x04,0x04,<br />0x05,0x06,0x06,0x07,0x08,0x08,0x09,0x09};<br /><br />void Disp_Temperature(void)<br />{<br /> display[4]=temp_data[0]&0x0f;<br /> display[0]=ditab[display[4]]; //查表得小数位的值<br /> <br /> display[4]=((temp_data[0]&0xf0)>>4)|((temp_data[1]&0x0f)<<4);<br /> display[3]=display[4]/100;<br /> display[1]=display[4]%100;<br /> display[2]=display[1]/10;<br /> display[1]=display[1]%10;<br /><br /> if(!display[3]) //高位为0，不显示<br /> { <br /> display[3]=0x0a; <br /> if(!display[2]) //次高位为0，不显示<br /> display[2]=0x0a;<br /> }<br /><br /> PORTA = 0xc6; //显示 C<br /> PORTC = 0x7f;<br /> delay_nms(1);<br /><br /> PORTA = 0x9c; //显示 ° <br /> PORTC = 0xbf;<br /> delay_nms(1);<br /><br /> PORTA =LEDData[display[0]]; //显示小数位<br /> PORTC = 0xdf;<br /> delay_nms(1);<br /><br /> PORTA =LEDData[display[1]]; //显示个位<br /> PORTA &=~_BV(PA7); //显示小数点<br /> PORTC = 0xef;<br /> delay_nms(1);<br /><br /> PORTA =LEDData[display[2]]; //显示十位<br /> PORTC = 0xf7;<br /> delay_nms(1);<br /><br /> PORTA =LEDData[display[3]]; //显示十位<br /> PORTC = 0xfb;<br /> delay_nms(1);<br /><br /> PORTC = 0xff; //关闭显示<br />}<br /> |
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