设计要求
通过内部ADC完成电位器RB2的输出电压检测，并显示在数码管上；
通过串口向PC端返回当前检测的电压值。
按键“S4”定义为发送按键，按下按键S4，串口向PC端发送当前检测的电压值。
串口发送格式：
U:1.25V\r\n
数码管显示格式如下图所示：
电压为1.25V（数码管最高位显示标识符U）
备注
单片机IRC振荡器频率设置为12MHz。
按键模式：BTN；扩展方式：IO模式。
串口波特率：9600。
代码
sys.h
#ifndef __SYS_H__
#define __SYS_H__#include <STC15F2K60S2.H>
//sys.c
extern bit flag_send;
extern float Vrb2;
void init74hc138(unsigned char n);
void init();
//seg_key.c
void Key_Loop();
void Seg_Loop();
void ui();
//iic.c
float get_Vrb2();
#endif main.c
#include "sys.h"
#include "stdio.h"
bit flag1=0;
bit flag2=0;
bit flag3=0;
void Timer0_Init(void) //100微秒@12.000MHz
{AUXR &= 0x7F; //定时器时钟12T模式TMOD &= 0xF0; //设置定时器模式TL0 = 0x9C; //设置定时初始值TH0 = 0xFF; //设置定时初始值TF0 = 0; //清除TF0标志TR0 = 1; //定时器0开始计时ET0 = 1; //使能定时器0中断EA = 1;
}
void UartInit(void) //9600bps@12.000MHz
{SCON = 0x50; //8位数据,可变波特率AUXR |= 0x40; //定时器时钟1T模式AUXR &= 0xFE; //串口1选择定时器1为波特率发生器TMOD &= 0x0F; //设置定时器模式TL1 = 0xC7; //设置定时初始值TH1 = 0xFE; //设置定时初始值ET1 = 0; //禁止定时器中断TR1 = 1; //定时器1开始计时ES = 1;EA = 1;
}
char putchar(char ch){SBUF=ch;while(!TI);TI=0;return ch;
}
void main(){init();Timer0_Init();UartInit();while(1){if(flag1){flag1=0;Seg_Loop();}if(flag2){flag2=0;Key_Loop();}if(flag3){flag3=0;Vrb2=get_Vrb2();ui();}if(flag_send){flag_send=0;printf("U:%.2fV\r\n",Vrb2);}}
}
void Timer0_Isr(void) interrupt 1
{static unsigned char count1=0;static unsigned char count2=0;static unsigned int count3=0;count1++;count2++;count3++;if(count1==2){count1=0;flag1=1;}if(count2==50){count2=0;flag2=1;}if(count3==1000){count3=0;flag3=1;}
}
void uart() interrupt 4
{if(RI){RI=0;}
}sys.c
#include "sys.h"
bit flag_send=0;
float Vrb2;
void init74hc138(unsigned char n){P2=(P2&0x1f)|(n<<5);P2&=0x1f;
}
void init(){P0=0x00;init74hc138(5);P0=0xff;init74hc138(4);
}seg_key.c
#include "sys.h"
code unsigned char Seg_Table[]={0xc0,//00xf9,//10xa4,//20xb0,//30x99,//40x92,//50x82,//60xf8,//70x80,//80x90,//90xc1,//U 100xff //熄灭 11
};
unsigned char Seg_Buff[8]={11,11,11,11,11,11,11,11};
unsigned char keyval,keyold,keyup,keydown;
void Key_Loop(){if(P33==0)keyval=4;keydown=keyval&(keyold^keyval);keyup=~keyval&(keyold^keyval);if(keyval==4&&keyold!=4) flag_send=1;keyold=keyval;keyval=0;
}
void seg(unsigned char addr,num){P0=0xff;init74hc138(7);P0=0x01<<addr;init74hc138(6);P0=Seg_Table[num];if(addr==5) P0&=0x7f;init74hc138(7);
}
void Seg_Loop(){static unsigned char i=0;seg(i,Seg_Buff[i]);i++;if(i==8) i=0;
}
void ui(){Seg_Buff[7]=(int)(Vrb2*100+0.5)%10;Seg_Buff[6]=(int)(Vrb2*10+0.05)%10;Seg_Buff[5]=(int)(Vrb2+0.005)%10;Seg_Buff[4]=11;Seg_Buff[3]=11;Seg_Buff[2]=11;Seg_Buff[1]=11;Seg_Buff[0]=10;
}iic.c
#include "sys.h"
#include "intrins.h"
#define DELAY_TIME 10
sbit scl=P2^0;
sbit sda=P2^1;
static void I2C_Delay(unsigned char n)
{do{_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_(); }while(n--);
}//
void I2CStart(void)
{sda = 1;scl = 1;I2C_Delay(DELAY_TIME);sda = 0;I2C_Delay(DELAY_TIME);scl = 0;
}//
void I2CStop(void)
{sda = 0;scl = 1;I2C_Delay(DELAY_TIME);sda = 1;I2C_Delay(DELAY_TIME);
}//
void I2CSendByte(unsigned char byt)
{unsigned char i;for(i=0; i<8; i++){scl = 0;I2C_Delay(DELAY_TIME);if(byt & 0x80){sda = 1;}else{sda = 0;}I2C_Delay(DELAY_TIME);scl = 1;byt <<= 1;I2C_Delay(DELAY_TIME);}scl = 0;
}//
unsigned char I2CReceiveByte(void)
{unsigned char da;unsigned char i;for(i=0;i<8;i++){ scl = 1;I2C_Delay(DELAY_TIME);da <<= 1;if(sda) da |= 0x01;scl = 0;I2C_Delay(DELAY_TIME);}return da;
}//
unsigned char I2CWaitAck(void)
{unsigned char ackbit;scl = 1;I2C_Delay(DELAY_TIME);ackbit = sda; scl = 0;I2C_Delay(DELAY_TIME);return ackbit;
}//
void I2CSendAck(unsigned char ackbit)
{scl = 0;sda = ackbit; I2C_Delay(DELAY_TIME);scl = 1;I2C_Delay(DELAY_TIME);scl = 0; sda = 1;I2C_Delay(DELAY_TIME);
}
unsigned char adc(unsigned char addr){unsigned char temp;EA=0;I2CStart();I2CSendByte(0x90);I2CWaitAck();I2CSendByte(addr);I2CWaitAck();I2CStart();I2CSendByte(0x91);I2CWaitAck();temp=I2CReceiveByte();I2CSendAck(1);I2CStop();EA=1;return temp;
}
float get_Vrb2(){return (float)adc(3)/255*5.0;
}测评结果
函数详解)
