蓝桥杯单片机刷题——串口发送实时时钟

设计要求

读取DS1302时钟芯片的时、分、秒，当S9按键按下时，串口发送一次当前时、分、秒。

串口发送格式如下图所示：

Time:00:00:00

备注：

单片机IRC振荡器频率：12MHz。

串口通信波特率：9600bps。

按键模式：BTN；扩展方式：IO模式

代码

sys.h

cpp 复制代码

#ifndef __SYS_H__
#define __SYS_H__

#include <STC15F2K60S2.H>
#include "intrins.h"
extern unsigned char time[3];
extern bit flag;
void init74hc138(unsigned char n);
void init();
void Key_Loop();
void w_ds1302();
void r_ds1302();


#endif

main.c

cpp 复制代码

#include "sys.h"
unsigned char *str="Time:";
bit flag_key=0;
bit flag_time=0;
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;
}
void Timer2_Init(void)		//100微秒@12.000MHz
{
	AUXR |= 0x04;			//定时器时钟1T模式
	T2L = 0x50;				//设置定时初始值
	T2H = 0xFB;				//设置定时初始值
	AUXR |= 0x10;			//定时器2开始计时
	IE2 |= 0x04;			//使能定时器2中断
	EA=1;
}
void send_uart_date(unsigned char date){
	SBUF=date;
	while(TI==0);
	TI=0;
}
void send_uart_str(unsigned char *str){
	while(*str!='\0'){
		send_uart_date(*str++);
	}
}
void send_uart_time(){
	send_uart_str(str);
	send_uart_date(time[2]/10+'0');
	send_uart_date(time[2]%10+'0');
	send_uart_date(':');
	send_uart_date(time[1]/10+'0');
	send_uart_date(time[1]%10+'0');
	send_uart_date(':');
	send_uart_date(time[0]/10+'0');
	send_uart_date(time[0]%10+'0');
	send_uart_str("\r\n");
}
void main(){
	init();
	w_ds1302();
	UartInit();
	Timer2_Init();
	while(1){
		if(flag_key){
			flag_key=0;
			Key_Loop();
		}
		if(flag_time){
			flag_time=0;
			r_ds1302();
		}
		if(flag){
			flag=0;
			send_uart_time();
		}
	}
}
void uart() interrupt 4
{
	if(RI){
		RI=0;
	}
}
void Timer2_Isr(void) interrupt 12
{
	static unsigned char count=0;
	static unsigned int count1=0;
	count++;count1++;
	if(count==50){
		count=0;
		flag_key=1;
	}
	if(count1==5000){
		count1=0;
		flag_time=1;
	}
}

sys.c

cpp 复制代码

#include "sys.h"
unsigned char keyval,keyold,keyup,keydown;
bit flag=0;
void init74hc138(unsigned char n){
	P2=(P2&0x1f)|(n<<5);
	P2&=0x1f;
}
void init(){
	P0=0x00;
	init74hc138(5);
	P0=0xff;
	init74hc138(4);
}
void Key_Loop(){
	P32=0;
	keyval=0;
	if(P42==0)keyval=1;
	keydown=keyval&(keyold^keyval);
	keyup=~keyval&(keyold^keyval);
	if(keyval&&!keyold)flag=1;
	keyold=keyval;
}

ds1302.c

cpp 复制代码

#include "sys.h"
sbit SCK=P1^7;
sbit SDA=P2^3;
sbit RST=P1^3;
unsigned char time[]={0,0,0};
void Write_Ds1302(unsigned  char temp) 
{
	unsigned char i;
	for (i=0;i<8;i++)     	
	{ 
		SCK = 0;
		SDA = temp&0x01;
		temp>>=1; 
		SCK=1;
	}
}   

//
void Write_Ds1302_Byte( unsigned char address,unsigned char dat )     
{
 	RST=0;	_nop_();
 	SCK=0;	_nop_();
 	RST=1; 	_nop_();  
 	Write_Ds1302(address);	
 	Write_Ds1302(dat/10*16|dat%10);//十进制------>8421BCD
 	RST=0; 
}

//
unsigned char Read_Ds1302_Byte ( unsigned char address )
{
 	unsigned char i,temp=0x00;
	unsigned char dat1,dat2;
 	RST=0;	_nop_();
 	SCK=0;	_nop_();
 	RST=1;	_nop_();
 	Write_Ds1302(address);
 	for (i=0;i<8;i++) 	
 	{		
		SCK=0;
		temp>>=1;	
 		if(SDA)
 		temp|=0x80;	
 		SCK=1;
	} 
 	RST=0;	_nop_();
 	SCK=0;	_nop_();
	SCK=1;	_nop_();
	SDA=0;	_nop_();
	SDA=1;	_nop_();
	dat1=temp/16;
	dat2=temp%16;
	temp=dat1*10+dat2;
	return (temp);			
}
void w_ds1302(){
	unsigned char i,addr=0x80;
	Write_Ds1302_Byte(0x8e,0x00);
	for(i=0;i<3;i++){
		Write_Ds1302_Byte(addr,time[i]);
		addr+=2;
	}
	Write_Ds1302_Byte(0x8e,0x80);
}
void r_ds1302(){
	unsigned char i,addr=0x81;
	for(i=0;i<3;i++){
		time[i]=Read_Ds1302_Byte(addr);
		addr+=2;
	}
}