多量程数字电压表

1、 多量程数字电压表本毕设以stc89c52rc单片机为核心，利用adc0809采集外部电压进行转换显示，并采用串联电阻法，选取不同的量程。程序：#include/#include#define uint unsigned int#define uchar unsigned charsbit rs=p30;sbit e=p31;sbit start=p20;sbit out=p22;sbit ale=p23;sbit key1=p34;sbit key2=p35;sbit key3=p36;uchar num=1,flag=0;uint ad_data;uchar data table=0123

2、456789.v h:;void delay(uchar ms) /延时子函数 uchar j,i; for(i=ms;i0;i-) for(j=110;j0;j-);/写指令/void write_com(uchar com) /写指令函数 rs=0; p1=com; e=1; delay(1); e=0;/写数据/void write_data(uchar da) /写数据函数 rs=1; p1=da; e=1; delay(1); e=0; /初始化液晶/void lcd_init() write_com(0x38); /*显示模式设置*/ delay(5); write_com(0x3

3、8); delay(5); write_com(0x38); delay(5); write_com(0x38); write_com(0x08); /*显示关闭*/ write_com(0x01); /*显示清屏*/ write_com(0x06); /*显示光标移动设置*/ delay(5); write_com(0x0c); /*显示开及光标设置*/ write_com(0x83); write_data(table14); /初始化显示相关字符/void display_data(uchar add1,uchar add2,uint date) uchar i; write_com(0

4、x82); write_data(tablenum); /ad通道显示 write_com(0x80+add1*0x40+add2); /地址计算 delay(1); if(num=1) i=date/100; write_data(tablei); / i=date/10%10; write_data(tablei); write_data(table10); i=date%10; write_data(tablei); write_data(table11); if(num=2|num=3) i=date/100; write_data(tablei); /write_data(table

5、10); i=date/10%10; write_data(tablei); i=date%10; write_data(tablei); write_data(table11); write_data(table12); void key_scan() if(key1=0) delay(10); /消抖延时 if(key1=0) num=1; while(key1=0); if(key2=0) delay(10); /消抖延时 if(key2=0) num=2; while(key2=0); if(key3=0) delay(10); /消抖延时 if(key3=0) num=3; whil

6、e(key3=0);void int0_init() ea=1; it0=1; ex0=1;void ad_transform() p2&=0x0f;/ delay(2); ale=0; p2|=0x00+num*16; /地址计算 delay(1); ale=1; ale=0; start=0; start=1; start=0; void main() float aa=0.0; lcd_init(); /液晶屏初始化 int0_init(); /中断初始化while(1) key_scan(); /按键扫描函数 ad_transform(); delay(100); if(flag=1) ea=0; flag=0; aa=(float)ad_data; /ad转换函数 if(num=1) aa=(aa*200)/255; /标度转换此公式将ad值放大100倍 if(num=2) aa=(aa*200)/255; /标度转换此公式将ad值放大100倍 if(num=3) aa=(aa*500)/255; /标度转换此公式将ad值放大100倍 ea=1; display_data(0,4,(uint)aa);/数值显示 void it0() interrupt 0 out=1; flag+; ad_dat