RTC DS1307 示例

2026-07-07

概述

本文介绍如何在 睿擎工业开发平台 中创建并运行 RTC DS1307 实时时钟 示例工程。通过驱动 DS1307 实时时钟芯片，演示了基于 RT-Thread I2C 驱动框架完成时间读取、时间设置、BCD 码转换、12/24 小时制自适应解析等 RTC 专属功能。

DS1307 RTC

DS1307 是一款低功耗、全 BCD 码时钟日历实时时钟芯片。它通过 I2C 接口提供秒、分、时、日、星期、月和年信息，并支持闰年补偿。芯片内部包含一个电池备份电路，在主电源掉电时可自动切换到备用电池供电，确保时钟持续稳定运行。

关键特性

I2C 串行接口，从设备地址 0x68
内部振荡器可通过 CH（Clock Halt）位控制启停
支持 12 小时制（AM/PM）与 24 小时制两种时间格式
片上 56 字节非易失性 SRAM
备份电池自动切换，保证掉电走时

硬件连接

开发板的 I2C 与 RTC 硬件已经连接，RTC 芯片位置如图所示：

查手册获取 DS1307 的设备地址

根据 DS1307 数据手册可知：

DS1307 的 I2C 从设备地址为固定的 0x68（7 位地址）

构建与烧录

创建工程点击展开

构建工程点击展开

固件下载点击展开

核心示例代码

BCD 码与二进制互转

static rt_uint8_t bcd_to_bin(rt_uint8_t bcd)
{
    return ((bcd >> 4) * 10) + (bcd & 0x0F);
}

static rt_uint8_t bin_to_bcd(rt_uint8_t bin)
{
    return ((bin / 10) << 4) | (bin % 10);
}

I2C 寄存器写入

static rt_err_t ds1307_write_reg(rt_uint8_t reg, rt_uint8_t data)// ds1307 写寄存器
{
    rt_uint8_t buf[2];
    buf[0] = reg;
    buf[1] = data;

    struct rt_i2c_msg msg;
    msg.addr  = DS1307_I2C_ADDR;
    msg.flags = RT_I2C_WR;
    msg.buf   = buf;
    msg.len   = 2;

    if (rt_i2c_transfer(ds1307_i2c_bus, &msg, 1) == 1)
        return RT_EOK;

    return -RT_ERROR;
}

I2C 寄存器连续读取

static rt_err_t ds1307_read_regs(rt_uint8_t reg, rt_uint8_t *buf, rt_uint8_t len)// ds1307 读寄存器
{
    struct rt_i2c_msg msgs[2];

    msgs[0].addr  = DS1307_I2C_ADDR;
    msgs[0].flags = RT_I2C_WR;
    msgs[0].buf   = &reg;
    msgs[0].len   = 1;

    msgs[1].addr  = DS1307_I2C_ADDR;
    msgs[1].flags = RT_I2C_RD;
    msgs[1].buf   = buf;
    msgs[1].len   = len;

    if (rt_i2c_transfer(ds1307_i2c_bus, msgs, 2) == 2)
        return RT_EOK;

    return -RT_ERROR;
}

初始化与振荡器启动

rt_err_t ds1307_init(const char *i2c_bus_name)
{
    rt_uint8_t sec_reg = 0;

    ds1307_i2c_bus = (struct rt_i2c_bus_device *)rt_device_find(i2c_bus_name);//寻找 i2c 设备
    if (ds1307_i2c_bus == RT_NULL)
    {
        rt_kprintf("Can't find I2C bus: %s\n", i2c_bus_name);
        return -RT_ERROR;
    }

    if (ds1307_read_regs(DS1307_REG_SEC, &sec_reg, 1) == RT_EOK)// ds1307 读寄存器
    {
        if (sec_reg & DS1307_CH_BIT)
        {
            rt_kprintf("DS1307 oscillator is halted! Enabling it now...\n");
            ds1307_write_reg(DS1307_REG_SEC, sec_reg & ~DS1307_CH_BIT);
        }
    }

    rt_kprintf("DS1307 RTC driver init success.\n");
    return RT_EOK;
}

时间读取

rt_err_t ds1307_get_time(struct ds1307_time *time)// ds1307 获取时间
{
    rt_uint8_t rtc_buf[7];

    if (ds1307_i2c_bus == RT_NULL) return -RT_ERROR;

    if (ds1307_read_regs(DS1307_REG_SEC, rtc_buf, 7) != RT_EOK)// ds1307 读寄存器
    {
        return -RT_ERROR;
    }

    time->sec  = bcd_to_bin(rtc_buf[0] & 0x7F);
    time->min  = bcd_to_bin(rtc_buf[1]);

    if (rtc_buf[2] & DS1307_12_24_BIT)
    {
        rt_uint8_t hour = bcd_to_bin(rtc_buf[2] & 0x1F);
        if (rtc_buf[2] & 0x20)
        {
            time->hour = (hour == 12) ? 12 : (hour + 12);
        }
        else
        {
            time->hour = (hour == 12) ? 0 : hour;
        }
    }
    else
    {
        time->hour = bcd_to_bin(rtc_buf[2] & 0x3F);
    }

    time->week  = bcd_to_bin(rtc_buf[3]);
    time->day   = bcd_to_bin(rtc_buf[4]);
    time->month = bcd_to_bin(rtc_buf[5]);
    time->year  = bcd_to_bin(rtc_buf[6]) + 2000;

    return RT_EOK;
}

时间设置

rt_err_t ds1307_set_time(struct ds1307_time *time)// ds1307 设置时间
{
    rt_uint8_t write_buf[8];

    if (ds1307_i2c_bus == RT_NULL) return -RT_ERROR;

    write_buf[0] = DS1307_REG_SEC;
    write_buf[1] = bin_to_bcd(time->sec);
    write_buf[2] = bin_to_bcd(time->min);
    write_buf[3] = bin_to_bcd(time->hour);
    write_buf[4] = bin_to_bcd(time->week);
    write_buf[5] = bin_to_bcd(time->day);
    write_buf[6] = bin_to_bcd(time->month);
    write_buf[7] = bin_to_bcd(time->year - 2000);

    struct rt_i2c_msg msg;
    msg.addr  = DS1307_I2C_ADDR;
    msg.flags = RT_I2C_WR;
    msg.buf   = write_buf;
    msg.len   = 8;

    if (rt_i2c_transfer(ds1307_i2c_bus, &msg, 1) == 1)
    {
        return RT_EOK;
    }

    return -RT_ERROR;
}

示例代码

rtc_ds1307_example.c
static void rtc_ds1307_example(int argc, char **argv)
{
    if (ds1307_init("i2c1") != RT_EOK)
    {
        rt_kprintf("DS1307 init failed.\n");
        return;
    }

    if (argc > 1 && rt_strcmp(argv[1], "set") == 0)
    {
        if (argc < 9)
        {
            rt_kprintf("Usage: rtc_ds1307_example set <year> <mon> <day> <hour> <min> <sec> <week>\n");
            return;
        }

        struct ds1307_time set_tm;
        set_tm.year  = (rt_uint16_t)atoi(argv[2]);
        set_tm.month = (rt_uint8_t)atoi(argv[3]);
        set_tm.day   = (rt_uint8_t)atoi(argv[4]);
        set_tm.hour  = (rt_uint8_t)atoi(argv[5]);
        set_tm.min   = (rt_uint8_t)atoi(argv[6]);
        set_tm.sec   = (rt_uint8_t)atoi(argv[7]);
        set_tm.week  = (rt_uint8_t)atoi(argv[8]);

        if (ds1307_set_time(&set_tm) == RT_EOK)
            rt_kprintf("Set time success!\n");
        else
            rt_kprintf("Set time failed!\n");
    }
    else
    {
        struct ds1307_time get_tm;

        if (ds1307_get_time(&get_tm) == RT_EOK)
        {
            rt_kprintf("DS1307 Time: %04d-%02d-%02d %02d:%02d:%02d Week:%d\n",
                       get_tm.year, get_tm.month, get_tm.day,
                       get_tm.hour, get_tm.min, get_tm.sec, get_tm.week);
        }
        else
        {
            rt_kprintf("Get time failed!\n");
        }
    }
}

运行示例

操作步骤

将程序下载到开发板
打开串口终端连接开发板
系统在启动后 main 函数会自动调用 rtc_ds1307_example 读取当前时间
也可在终端输入 rtc_ds1307_example 命令读取时间
输入 rtc_ds1307_example set 2026 7 7 12 0 0 2 设置时间为 2026-07-07 12:00:00 星期二

预期结果

RT-Thread 终端
msh />DS1307 oscillator is halted! Enabling it now...
DS1307 RTC driver init success.
DS1307 Time: 2000-01-01 00:00:00 Week:1

msh />rtc_ds1307_example
DS1307 RTC driver init success.
DS1307 Time: 2000-01-01 00:00:32 Week:1

msh />rtc_ds1307_example set 2026 7 7 12 0 0 2
DS1307 RTC driver init success.
Set time success!

msh />rtc_ds1307_example
DS1307 RTC driver init success.
DS1307 Time: 2026-07-07 12:00:05 Week:2

01_os

02_peripheral

03_network

04_bus