基于C51单片机、AD1674和MAX7221的数字电压表（含原理图）

1、#include#include#define uchar unsigned char#define uint unsigned int#define addo (10.0/4095.0)/转换进率，12位精度(212-1=4095)，满量程为10v/*管脚定义*/sbit din = p25;sbit scl = p26;sbit cs = p27;sbit sts = p20;sbit cs1 = p21;sbit a0 = p22;sbit ce = p23;sbit rc = p24;static uchar disbuf8;/显示缓存/*微秒延时函数*/void delay_us(u

2、char n) uchar i;while(n-) for(i=0;i10;i+);/*毫秒延时函数*/void delay_ms(uint n)uchar i;while(n-) for(i=0;i100;i+);/*向max7221串行写一个字节的数据*/void writedata(uchar dat)uchar i;for(i=0;ii)?1:0; scl = 0; delay_us(2); scl = 1; delay_us(2);/*向max7221中指定的地址写入数据*/void max7221_write(uchar addr,uchar dat)cs = 0;writedat

3、a(addr);writedata(dat);cs = 1;/*max7221的初始化*/void max7221_initial(void)max7221_write(0x0a,0x07);/led亮度值设置为8/16max7221_write(0x0b,0x07);/扫描显示器的个数为8个max7221_write(0x0c,0x01);/正常操作模式（非掉电模式）max7221_write(0x0f,0x00);/正常显示模式（非测试模式）max7221_write(0x09,0xff);/对07的8个数据进行b型bcd译码/*led显示函数*/void display(void)uch

4、ar i;for(i=0;i8;i+) max7221_write(i+1,disbufi);/*读取ad1674转换结果*/uint ad1674_read(void) uint temp; uchar temp1,temp2; cs1 = 1; ce = 0; /初始化,关闭数据采集 cs1 = 0; a0 = 0; rc = 0; ce = 1; /ce=1,cs1=0,rc=0,a0=0启动12位温度转换 _nop_(); while(sts=1);/等待数据采集结束 ce = 0; /芯片使能关闭 rc = 1; a0 = 0; ce = 1; /ce=1,cs1=0,rc=1,12

5、/8=1,a0=0允许高八位数据并行输出 _nop_(); temp1 = p0;/读取转换结果的高八位 ce = 0;/芯片使能关闭 rc = 1; a0 = 1; ce = 1;/ce=1,cs1=0,rc=1,12/8=0,a0=1允许低四位数据并行输出 _nop_(); temp2 = p0;/读取转换结果的低四位 ce = 0; cs1 = 1;/关闭ad1674数据采集 temp = (temp14);/返回转换结果，右移四位是因为temp2为p0口的高四位/*向缓冲器中写入要显示的数据*/void hextobcd(uchar chn) uint temp; temp = (int)(ad1674_read()*addo*1000);/转换为可显示的实际温度值 disbuf0 = temp/10000; disbuf1 = (temp%10000/1000)|0x80;/带小数点的位显示 disbuf2 = temp%1000/100; disbuf3 = temp%100/10; disbuf4 = temp%10; disbuf5 = 15; disbuf6 = 15;/空显示 disbuf7 = chn;/显示通道号/*主函数*/void main