設計要求

通過內部ADC完成電位器RB2的輸出電壓檢測，并顯示在數碼管上；

通過串口向PC端返回當前檢測的電壓值。

按鍵“S4”定義為發送按鍵，按下按鍵S4，串口向PC端發送當前檢測的電壓值。

串口發送格式：

U:1.25V\r\n

數碼管顯示格式如下圖所示：

電壓為1.25V（數碼管最高位顯示標識符U）

備注

單片機IRC振蕩器頻率設置為12MHz。

????????按鍵模式：BTN；擴展方式：IO模式。

串口波特率：9600。

代碼

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;			//定時器時鐘12T模式TMOD &= 0xF0;			//設置定時器模式TL0 = 0x9C;				//設置定時初始值TH0 = 0xFF;				//設置定時初始值TF0 = 0;				//清除TF0標志TR0 = 1;				//定時器0開始計時ET0 = 1;				//使能定時器0中斷EA = 1;
}
void UartInit(void)		//9600bps@12.000MHz
{SCON = 0x50;		//8位數據,可變波特率AUXR |= 0x40;		//定時器時鐘1T模式AUXR &= 0xFE;		//串口1選擇定時器1為波特率發生器TMOD &= 0x0F;		//設置定時器模式TL1 = 0xC7;			//設置定時初始值TH1 = 0xFE;			//設置定時初始值ET1 = 0;			//禁止定時器中斷TR1 = 1;			//定時器1開始計時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 //熄滅 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;
}

測評結果