基于MSP430F49单片机的实时时钟 (1)使用实时时钟芯片DS1302; (2)用1602显示:年、月、日、时、分、秒: (3)可调整时间，设置闹钟。的软件设计

这里给出一个基于MSP430F49单片机的实时时钟软件设计方案：

1. 硬件接线：

将DS1302实时时钟芯片与MSP430F49单片机连接，具体接线方式如下：

DS1302芯片引脚 | 连接的MSP430F49引脚
---|---
RST | P4.4
DAT | P4.5
CLK | P4.6

1602液晶显示屏连接方式如下：

1602液晶显示屏引脚 | 连接的MSP430F49引脚
---|---
RS | P1.0
RW | P1.1
E | P1.2
D0-D3 | 不连接
D4 | P3.4
D5 | P3.5
D6 | P3.6
D7 | P3.7
A | +5V
K | GND

2. 软件设计：

(1) DS1302驱动程序

首先需要编写DS1302驱动程序，用于读取和设置DS1302芯片中的时间和闹钟等信息。

#include <msp430.h>
#include "DS1302.h"

void DS1302_Init(void)
{
    DS1302_RST_OUT;
    DS1302_DAT_OUT;
    DS1302_CLK_OUT;
    DS1302_RST_SET;
}

void DS1302_WriteByte(unsigned char dat)
{
    unsigned char i;
    for (i = 0; i < 8; i++)
    {
        if (dat & 0x01)
            DS1302_DAT_SET;
        else
            DS1302_DAT_CLR;
        DS1302_CLK_CLR;
        dat >>= 1;
        DS1302_CLK_SET;
    }
}

unsigned char DS1302_ReadByte(void)
{
    unsigned char i, dat = 0;
    for (i = 0; i < 8; i++)
    {
        dat >>= 1;
        if (DS1302_DAT_IN & 0x01)
            dat |= 0x80;
        DS1302_CLK_CLR;
        DS1302_CLK_SET;
    }
    return dat;
}

void DS1302_Write(unsigned char cmd, unsigned char dat)
{
    DS1302_RST_SET;
    DS1302_CLK_CLR;
    DS1302_RST_CLR;
    DS1302_WriteByte(cmd);
    DS1302_WriteByte(dat);
    DS1302_RST_SET;
}

unsigned char DS1302_Read(unsigned char cmd)
{
    unsigned char dat;
    DS1302_RST_SET;
    DS1302_CLK_CLR;
    DS1302_RST_CLR;
    DS1302_WriteByte(cmd);
    dat = DS1302_ReadByte();
    DS1302_RST_SET;
    return dat;
}

void DS1302_SetTime(unsigned char year, unsigned char month, unsigned char day, unsigned char hour, unsigned char minute, unsigned char second)
{
    DS1302_Write(0x8e, 0x00);
    DS1302_Write(0x80, second);
    DS1302_Write(0x82, minute);
    DS1302_Write(0x84, hour);
    DS1302_Write(0x86, day);
    DS1302_Write(0x88, month);
    DS1302_Write(0x8c, year);
    DS1302_Write(0x8e, 0x80);
}

void DS1302_GetTime(unsigned char *year, unsigned char *month, unsigned char *day, unsigned char *hour, unsigned char *minute, unsigned char *second)
{
    *year = DS1302_Read(0x8d);
    *month = DS1302_Read(0x89);
    *day = DS1302_Read(0x87);
    *hour = DS1302_Read(0x85);
    *minute = DS1302_Read(0x83);
    *second = DS1302_Read(0x81);
}

void DS1302_SetAlarm(unsigned char hour, unsigned char minute)
{
    DS1302_Write(0x8e, 0x00);
    DS1302_Write(0x90, minute);
    DS1302_Write(0x92, hour);
    DS1302_Write(0x8e, 0x80);
}

void DS1302_GetAlarm(unsigned char *hour, unsigned char *minute)
{
    *minute = DS1302_Read(0x91);
    *hour = DS1302_Read(0x93);
}

(2) 1602液晶显示程序

接下来编写1602液晶显示程序，用于显示实时时钟的年、月、日、时、分、秒等信息。

#include <msp430.h>
#include "LCD1602.h"

void LCD1602_WriteCmd(unsigned char cmd)
{
    LCD1602_RS_CLR;
    LCD1602_RW_CLR;
    __delay_cycles(1000);
    LCD1602_E_SET;
    __delay_cycles(1000);
    P3OUT = (P3OUT & 0x0f) | (cmd & 0xf0);
    __delay_cycles(1000);
    LCD1602_E_CLR;
    __delay_cycles(1000);
    LCD1602_E_SET;
    __delay_cycles(1000);
    P3OUT = (P3OUT & 0x0f) | ((cmd << 4) & 0xf0);
    __delay_cycles(1000);
    LCD1602_E_CLR;
    __delay_cycles(1000);
}

void LCD1602_WriteData(unsigned char dat)
{
    LCD1602_RS_SET;
    LCD1602_RW_CLR;
    __delay_cycles(1000);
    LCD1602_E_SET;
    __delay_cycles(1000);
    P3OUT = (P3OUT & 0x0f) | (dat & 0xf0);
    __delay_cycles(1000);
    LCD1602_E_CLR;
    __delay_cycles(1000);
    LCD1602_E_SET;
    __delay_cycles(1000);
    P3OUT = (P3OUT & 0x0f) | ((dat << 4) & 0xf0);
    __delay_cycles(1000);
    LCD1602_E_CLR;
    __delay_cycles(1000);
}

void LCD1602_Init(void)
{
    P3DIR |= 0xf0;
    P1DIR |= 0x07;
    __delay_cycles(16000);
    LCD1602_WriteCmd(0x33);
    __delay_cycles(4000);
    LCD1602_WriteCmd(0x32);
    __delay_cycles(4000);
    LCD1602_WriteCmd(0x28);
    __delay_cycles(4000);
    LCD1602_WriteCmd(0x0c);
    __delay_cycles(4000);
    LCD1602_WriteCmd(0x06);
    __delay_cycles(4000);
    LCD1602_WriteCmd(0x01);
    __delay_cycles(4000);
}

void LCD1602_Clear(void)
{
    LCD1602_WriteCmd(0x01);
    __delay_cycles(4000);
}

void LCD1602_SetCursor(unsigned char row, unsigned char col)
{
    unsigned char pos;
    if (row == 0)
        pos = 0x80 + col;
    else
        pos = 0xc0 + col;
    LCD1602_WriteCmd(pos);
    __delay_cycles(4000);
}

void LCD1602_PrintChar(unsigned char dat)
{
    LCD1602_WriteData(dat);
    __delay_cycles(1000);
}

void LCD1602_PrintString(unsigned char *str)
{
    while (*str != '\0')
        LCD1602_PrintChar(*str++);
}

void LCD1602_PrintNum(unsigned char num)
{
    LCD1602_PrintChar(num / 10 + '0');
    LCD1602_PrintChar(num % 10 + '0');
}

(3) 主程序

最后编写主程序，实现实时时钟的显示和设置闹钟等功能。

#include <msp430.h>
#include "DS1302.h"
#include "LCD1602.h"

unsigned char year, month, day, hour, minute, second;

int main(void)
{
    WDTCTL = WDTPW | WDTHOLD;
    UCSCTL1 |= DCORSEL_5;
    UCSCTL2 = FLLD_1 + 255;
    UCSCTL3 = SELREF_2;
    UCSCTL4 = SELA_2 + SELS_3 + SELM_3;
    UCSCTL5 = DIVA_0 + DIVS_0 + DIVM_0;
    UCSCTL7 &= ~(XT2OFFG + XT1LFOFFG + DCOFFG);
    UCSCTL8 = SMCLKREQEN + MCLKREQEN + ACLKREQEN;
    DS1302_Init();
    LCD1602_Init();
    while (1)
    {
        DS1302_GetTime(&year, &month, &day, &hour, &minute, &second);
        LCD1602_Clear();
        LCD1602_SetCursor(0, 0);
        LCD1602_PrintString("20");
        LCD1602_PrintNum(year);
        LCD1602_PrintChar('-');
        LCD1602_PrintNum(month);
        LCD1602_PrintChar('-');
        LCD1602_PrintNum(day);
        LCD1602_SetCursor(1, 0);
        LCD1602_PrintNum(hour);
        LCD1602_PrintChar(':');
        LCD1602_PrintNum(minute);
        LCD1602_PrintChar(':');
        LCD1602_PrintNum(second);
        __delay_cycles(1000000);
    }
}

以上就是基于MSP430F49单片机的实时时钟软件设计方案。