刚刚写完DS3231时钟芯片的驱动程序。这里开源出来供大家使用。需要的自取。

先简单介绍下这个芯片，然后直接给驱动代码以及示例代码。

DS3231简介

简介

DS3231是一款低成本、高精度I2C实时时钟(RTC)，具有集成的温补晶体振荡器(TCXO)和晶体。该器件包含电池输入端，断开主电源时认可保持精确的计时。其提供年、月、日、星期、时、分、秒信息，提供有效期到2100年的闰年补偿。

其带有两个提供不同精度的日历闹钟，可在指定时刻在引脚上产生中断信号。

支持快速(400kHz)I2C接口通讯。

时钟精度在0℃到+40℃为±2ppm，即一个月可能偏离5s多；在-40℃到+85℃为±3.5ppm。

除了时钟外，还提供精度为±3℃的数字温度传感器输出，内部会使用这个温度传感器自动进行补偿以保证时间精度。

典型工作电路

框图

寄存器

DS3231提供如下寄存器：

与DS3231的控制和交互就是通过存取这几个寄存器来实现的，驱动代码中提供了所有寄存器的结构体以及对寄存器的存取函数。

具体寄存器的意义请自己参照数据手册。

与芯片的I2C通讯

I2C通讯的基本原理可以见我的上一个文章/lin_strong/article/details/80259571，翻译的MC9S12XEP100的数据手册，里头有对I2C通讯的详细描述。

DS3231的主叫地址固定为0b1101000，其内部存在一个寄存器指针，指向下一次读/写的寄存器，每次读/写一次后指针都会自增1，到最后一个寄存器后再指向第一个寄存器。

进行写操作时第一个数据字节会对指针值进行修改。

驱动中提供的函数即封装了这个过程。

代码及测试

驱动代码

DS3231Driver.h

/***********************************************************************************************DS3231 DRIVER MODULE* DS3231驱动模块** File : DS3231Driver.h* By : Lin Shijun(/lin_strong)* Date: /05/14* version: V1.0* History: /05/14 V1.0 the prototype**********************************************************************************************/#ifndef DS3231_DRIVER_H#define DS3231_DRIVER_H/**********************************************************************************************MISCELLANEOUS*********************************************************************************************/#ifndef FALSE#define FALSE 0#endif#ifndef TRUE#define TRUE1#endif/********************************************************************************************CONSTANT*******************************************************************************************/// address of registertypedef enum{RegAddr_Sec, // Seconds 00-59RegAddr_Min, // Minutes 00-59RegAddr_Hour, // Hours1–12 + AM/PM 00–23RegAddr_Day, // Day 1 - 7RegAddr_Date, // Data 01-31RegAddr_CMon, // Century and month Century + 01–12RegAddr_Year, // Year 00 - 99RegAddr_Sec_A1, // Alarm 1 Seconds00-59RegAddr_Min_A1, // Alarm 1 Minutes00-59RegAddr_Hour_A1,// Alarm 1 Hours 1–12 + AM/PM 00–23RegAddr_Da_A1, // Alarm 1 Day/Date1 - 7 / 1 – 31RegAddr_Min_A2, // Alarm 2 Minutes00-59RegAddr_Hour_A2,// Alarm 2 Hours 1–12 + AM/PM 00–23RegAddr_Da_A2, // Alarm 2 Day/Date1 - 7 / 1 – 31RegAddr_Control,// ControlRegAddr_CtlStat,// Control/StatusRegAddr_AgOfset,// Aging offsetRegAddr_TempMSB,// MSB of TempRegAddr_TempLSB,// LSB of Temp}DS3231REG_ADDR;#define DS3231REG_ADDR_MAX RegAddr_TempLSB/********************************************************************************************* CONFIGURE 主配置********************************************************************************************/#define DS3231_CALLADDR0b1101000 // DS32331的主叫地址/****************************************************************************************** ERROR CODES*****************************************************************************************/#define DS3231_ERR_NULL 0// if success#define DS3231_ERR_COMM 1// any error in communication#define DS3231_ERR_REG 2// wrong register #define DS3231_ERR_ARG 3// if wrong argument/******************************************************************************************** TYPE DEFINE*******************************************************************************************/// struct of DS3231 register typedef struct {unsigned int sec_sd: 4; // ones digit of second 秒的个位unsigned int sec_td: 3; // tens digit of second 秒的十位unsigned int : 1;} REG_SEC;typedef struct {unsigned int min_sd: 4; // ones digit of minute 分的个位unsigned int min_td: 3; // tens digit of minute 分的十位unsigned int : 1;} REG_MIN;typedef union {struct{unsigned int hour_sd:4; // ones digit of hour 分的个位unsigned int hour_td:1; // tens digit of hour 分的个位unsigned int isPM :1; // whether is pmunsigned int is12sys:1; // whether is 12 hours system. unsigned int :1;}SYS12;struct{unsigned int hour_sd:4; // ones digit of hour 分的个位unsigned int hour_td:2; // tens digit of hour 分的个位unsigned int is12sys:1; // whether is 12 hours system. unsigned int :1;}SYS24;} REG_HOUR;typedef struct {unsigned int day : 3; // the day of the week unsigned int : 5;} REG_DAY;typedef struct {unsigned int date_sd: 4; // ones digit of second 秒的个位unsigned int date_td: 2; // tens digit of second 秒的十位unsigned int : 2;} REG_DATE;typedef struct {unsigned int mon_sd: 4; // ones digit of month 月的个位unsigned int mon_td: 1; // tens digit of month 月的个位unsigned int : 2; unsigned int century:1; // hundreds digit of year} REG_CMON;typedef struct {unsigned int year_sd: 4; // ones digit of year 月的个位unsigned int year_td: 4; // tens digit of year 月的个位} REG_YEAR;typedef struct {unsigned int sec_sd: 4; // ones digit of second 秒的个位unsigned int sec_td: 3; // tens digit of second 秒的十位unsigned int A1M1 : 1;} REG_SEC_A1;typedef struct {unsigned int min_sd: 4; // ones digit of minute 分的个位unsigned int min_td: 3; // tens digit of minute 分的十位unsigned int A1M2 : 1;} REG_MIN_A1;typedef union {struct{unsigned int hour_sd:4; // ones digit of hour 分的个位unsigned int hour_td:1; // tens digit of hour 分的个位unsigned int isPM :1; // whether is pmunsigned int is12sys:1; // whether is 12 hours system. unsigned int A1M3 :1;}SYS12;struct{unsigned int hour_sd:4; // ones digit of hour 分的个位unsigned int hour_td:2; // tens digit of hour 分的个位unsigned int is12sys:1; // whether is 12 hours system. unsigned int A1M3 :1;}SYS24;} REG_HOUR_A1;typedef union {struct{unsigned int day : 4; // the day of the week unsigned int : 2;unsigned int isDY : 1; // day selectedunsigned int A1M4 : 1;}DAY;struct{unsigned int date_sd: 4; // ones digit of dateunsigned int date_td: 2; // tens digit of dateunsigned int isDY : 1; // day selectedunsigned int A1M4 : 1;}DATE;} REG_DA_A1;typedef struct {unsigned int min_sd: 4; // ones digit of minute 分的个位unsigned int min_td: 3; // tens digit of minute 分的十位unsigned int A2M2 : 1;} REG_MIN_A2;typedef union {struct{unsigned int hour_sd:4; // ones digit of hour 分的个位unsigned int hour_td:1; // tens digit of hour 分的个位unsigned int isPM :1; // whether is pmunsigned int is12sys:1; // whether is 12 hours system. unsigned int A2M3 :1;}SYS12;struct{unsigned int hour_sd:4; // ones digit of hour 分的个位unsigned int hour_td:2; // tens digit of hour 分的个位unsigned int is12sys:1; // whether is 12 hours system. unsigned int A2M3 :1;}SYS24;} REG_HOUR_A2;typedef union {struct{unsigned int day : 4; // the day of the week unsigned int : 2;unsigned int isDY : 1; // day selectedunsigned int A2M4 : 1;}DAY;struct{unsigned int date_sd: 4; // ones digit of dateunsigned int date_td: 2; // tens digit of dateunsigned int isDY : 1; // day selectedunsigned int A2M4 : 1;}DATE;} REG_DA_A2;typedef struct{unsigned int A1IE : 1;unsigned int A2IE : 1;unsigned int INTCN : 1;unsigned int RS1 : 1;unsigned int RS2 : 1;unsigned int CONV : 1;unsigned int BBSQW : 1;unsigned int EOSC : 1;} REG_CONTROL;typedef struct{unsigned int A1IF : 1;unsigned int A2IF : 1;unsigned int BSY : 1;unsigned int EN32kHz: 1;unsigned int : 3;unsigned int OSF : 1;} REG_CTLSTAT;typedef struct{unsigned int DATA : 7;unsigned int SIGN : 1;} REG_AGOFSET;typedef struct{char DATA;} REG_TEMPMSB;typedef struct{unsigned int: 6;unsigned int DATA : 2;} REG_TEMPLSB;// type of moduletypedef struct {REG_SEC sec;REG_MIN min;REG_HOUR hour;REG_DAY day;REG_DATE date;REG_CMON cmon;REG_YEAR year;} TIME_STRUCT,*pTIME_STRUCT;typedef struct{REG_TEMPMSB integral;// integral partREG_TEMPLSB fractional; // fractional part} TEMP_STRUCT,*pTEMP_STRUCT;typedef struct{unsigned int errcode : 4; // see DS3231_ERR_XXXunsigned int commerr : 4; // hold the errcode by user defined iic functions.} DS3231_ERRCODE;/**************************************************************************************FUNCTION PROTOTYPES 函数原型*************************************************************************************/unsigned char DS3231_Init(void);DS3231_ERRCODE DS3231_GetReg(DS3231REG_ADDR reg,unsigned char *rst);DS3231_ERRCODE DS3231_SetReg(DS3231REG_ADDR reg,unsigned char value);DS3231_ERRCODE DS3231_GetRegs(DS3231REG_ADDR reg,unsigned char *pBuf,unsigned short len);DS3231_ERRCODE DS3231_SetRegs(DS3231REG_ADDR reg,unsigned char *pBuf,unsigned short len);DS3231_ERRCODE DS3231_SetTime(pTIME_STRUCT val);DS3231_ERRCODE DS3231_GetTime(pTIME_STRUCT rst);DS3231_ERRCODE DS3231_GetTemp(pTEMP_STRUCT rst);// 用户需要实现这几个函数以使模块能与DS3231进行IIC通讯// Arguments: calAddr7bits calling address// pBuf pointer to the send/recv buffer// lenlength of datas to be send/recv// rstpointer to the return value// valthe byte to send// return : 0 if success// 1 - 15 errcode of IIC communication. //meaning of errcode of these functions should be exactly same. extern unsigned char IIC_ReadBurst(unsigned char calAddr,unsigned char *pBuf,unsigned short len);extern unsigned char IIC_SendBurst(unsigned char calAddr,unsigned char *pBuf,unsigned short len);extern unsigned char IIC_ReadByte(unsigned char calAddr,unsigned char *rst);extern unsigned char IIC_SendByte(unsigned char calAddr,unsigned char val);/**************************************************************************************ERROR CHECK 错误检查*************************************************************************************/#endif // of DS3231_DRIVER_H

DS3231Driver.c

/***********************************************************************************************DS3231 DRIVER MODULE* DS3231驱动模块** File : DS3231Driver.c* By : Lin Shijun(/lin_strong)* Date: /05/14* version: V1.0* History: /05/14 V1.0 the prototype**********************************************************************************************//*********************************************************************************************** INCLUDES**********************************************************************************************/#include <string.h>#include "DS3231Driver.h"/*********************************************************************************************** LOCAL FUNCTION**********************************************************************************************/#define regCheck()if(reg > DS3231REG_ADDR_MAX){err.errcode = DS3231_ERR_REG; return err;}#define lenCheck()if(len > (DS3231REG_ADDR_MAX + 1) || len == 0){err.errcode = DS3231_ERR_ARG; return err;}/*********************************************************************************************** LOCAL VARIABLE**********************************************************************************************/// 发送缓存static unsigned char Sendbuf[DS3231REG_ADDR_MAX + 2];/***********************************************************************************************DS3231_Init()** Description : Initialize DS3231 support hardware(marco style). 初始化DS3231硬件** Arguments : ** Return: DS3231_ERR_NULL if success.** Note(s): **********************************************************************************************/unsigned char DS3231_Init(void){return DS3231_ERR_NULL;}/***********************************************************************************************************DS3231_getReg()** Description : get a register value of DS3231.** Arguments : reg the register to get value.*rst return value of result.** Return: .errcode:* DS3231_ERR_NULL if success.* DS3231_ERR_COMM if error.* DS3231_ERR_REGif unknown register.*.commerr:* errcode returned by user defined IIC functions if DS3231_ERR_COMM.** Note: **********************************************************************************************************/DS3231_ERRCODE DS3231_GetReg(DS3231REG_ADDR reg,unsigned char *rst){DS3231_ERRCODE err = {0};unsigned char commerr;regCheck();if((commerr = IIC_SendByte(DS3231_CALLADDR,(unsigned char)reg)) == 0 && // 写入寄存器指针(commerr = IIC_ReadByte(DS3231_CALLADDR,rst)) == 0){// 然后读取一个字节err.errcode = DS3231_ERR_NULL;}else{err.errcode = DS3231_ERR_COMM;}merr = commerr;return err;}/***********************************************************************************************************DS3231_SetReg()** Description : set a register of DS3231.** Arguments : reg the register to get value.*rst return value of result.** Return: .errcode:* DS3231_ERR_NULL if success.* DS3231_ERR_COMM if error.* DS3231_ERR_REGif unknown register.*.commerr:* errcode returned by user defined IIC functions if DS3231_ERR_COMM.* Note: **********************************************************************************************************/DS3231_ERRCODE DS3231_SetReg(DS3231REG_ADDR reg,unsigned char value){DS3231_ERRCODE err = {0};unsigned char commerr;regCheck();Sendbuf[0] = (unsigned char)reg;Sendbuf[1] = value;if((commerr = IIC_SendBurst(DS3231_CALLADDR,Sendbuf,2)) == 0)err.errcode = DS3231_ERR_NULL;elseerr.errcode = DS3231_ERR_COMM;merr = commerr;return err;}/***********************************************************************************************************DS3231_GetRegs()** Description : get sereval registers' value of DS3231.** Arguments : regthe first register to get value.*pBufreturn value of register.*len how many registers to get value (1 - (DS3231REG_ADDR_MAX + 1))** Return: .errcode:* DS3231_ERR_NULL if success.* DS3231_ERR_COMM if error.* DS3231_ERR_REGif unknown register.* DS3231_ERR_ARGif len out of range.*.commerr:* errcode returned by user defined IIC functions if DS3231_ERR_COMM.* Note: **********************************************************************************************************/DS3231_ERRCODE DS3231_GetRegs(DS3231REG_ADDR reg,unsigned char *pBuf,unsigned short len){DS3231_ERRCODE err = {0};unsigned char commerr;regCheck();lenCheck();if((commerr = IIC_SendByte(DS3231_CALLADDR,(unsigned char)reg)) == 0 && // 写入寄存器指针(commerr = IIC_ReadBurst(DS3231_CALLADDR,pBuf,len)) == 0){// 然后读取一个字节err.errcode = DS3231_ERR_NULL;}else{err.errcode = DS3231_ERR_COMM;}merr = commerr;return err;}/***********************************************************************************************************DS3231_SetRegs()* * Description : set sereval registers' value of DS3231.* * Arguments : reg the first register to set value.*pBufpoint to the value of registers to set.*len how many registers to set value (1 - (DS3231REG_ADDR_MAX + 1))* * Return: .errcode:* DS3231_ERR_NULL if success.* DS3231_ERR_COMM if error.* DS3231_ERR_REGif unknown register * DS3231_ERR_ARGif len out of range.*.commerr:* errcode returned by user defined IIC functions if DS3231_ERR_COMM.** Note: **********************************************************************************************************/DS3231_ERRCODE DS3231_SetRegs(DS3231REG_ADDR reg,unsigned char *pBuf,unsigned short len){DS3231_ERRCODE err = {0};unsigned char commerr;regCheck();lenCheck();Sendbuf[0] = (unsigned char)reg;memcpy(Sendbuf+1,pBuf,len);if((commerr = IIC_SendBurst(DS3231_CALLADDR,Sendbuf,len + 1)) == 0){// 写入寄存器指针err.errcode = DS3231_ERR_NULL;}else{err.errcode = DS3231_ERR_COMM;}merr = commerr;return err;}/***********************************************************************************************************DS3231_SetTime()* * Description : set time of DS3231.* * Arguments : val the time to set* * Return: .errcode:* DS3231_ERR_NULL if success.* DS3231_ERR_COMM if error.*.commerr:* errcode returned by user defined IIC functions if DS3231_ERR_COMM.* Note: **********************************************************************************************************/DS3231_ERRCODE DS3231_SetTime(pTIME_STRUCT val){return DS3231_SetRegs(RegAddr_Sec,(unsigned char *)val,sizeof(TIME_STRUCT));}/***********************************************************************************************************DS3231_GetTime()* * Description : get time of DS3231.* * Arguments : rst the time result.* * Return: .errcode:* DS3231_ERR_NULL if success.* DS3231_ERR_COMM if error.*.commerr:* errcode returned by user defined IIC functions if DS3231_ERR_COMM.* Note: **********************************************************************************************************/DS3231_ERRCODE DS3231_GetTime(pTIME_STRUCT rst){return DS3231_GetRegs(RegAddr_Sec,(unsigned char *)rst,sizeof(TIME_STRUCT));}/***********************************************************************************************************DS3231_GetTemp()* * Description : get temperature measured by DS3231.* * Arguments : rst return the temperature measured.*= (rst->integral.DATA).(rst->fractional.DATA * 0.25)*for example:* if rst->integral.DATA = -4, rst->fractional.DATA = 3* then temperature = -4.75 C* if rst->integral.DATA = 25, rst->fractional.DATA = 1* then temperature = +25.25 C** Return: .errcode:* DS3231_ERR_NULL if success.* DS3231_ERR_COMM if error.*.commerr:* errcode returned by user defined IIC functions if DS3231_ERR_COMM.* Note : 1. DS3231 will measure temperature every 64 seconds once powered* by Vcc or once communicated when powerd by battery.*2. you can also start the convertion by set CONV in Control * register.**********************************************************************************************************/DS3231_ERRCODE DS3231_GetTemp(pTEMP_STRUCT rst){return DS3231_GetRegs(RegAddr_TempMSB,(unsigned char *)rst,sizeof(TEMP_STRUCT));}

DS3231_G/SetReg(s)对DS3231寄存器读写操作进行封装。

模块要求用户按照要求提供错误码风格的IIC通讯函数，并在发生通讯错误时把用户函数的错误码一同返回。

由于时间和温度的使用较频繁，提供了专门的读写函数。

时间转换助手

DS3231TimeHelper.h

/**********************************************************************************************DS3231 TIME HELPER MODULE** File : DS3231TimeHelper.h* By : Lin Shijun(/lin_strong)* Date: /09/26* version: V1.0* History: * note : the convert interfaces for DS3231 time.**********************************************************************************************/#ifndef _DS3231TimeHelper_H#define _DS3231TimeHelper_H#include "DS3231Driver.h"#include "TimeExt.h"#include "common.h"// only support year from 2000 to 2199#define DS3231_BASEYEAR 2000void DS3231TimeToSystemTime(struct tm *dst, const TIME_STRUCT *src);void SystemTimeToDS3231Time(TIME_STRUCT *dst, const struct tm *src);BOOL DS3231TimeValid(const TIME_STRUCT *time);#endif

其中TimeExt.h是引用的我自己写的time标准库实现：

/lin_strong/article/details/102619616

只是为了节省空间直接用了里头的

const int16_t TimeExt_lpdays[] = {-1, 30, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365}; const int16_t TimeExt_days[] = {-1, 30, 58, 89, 119, 150, 180, 211, 242, 272, 303, 333, 364};

如果不需要使用这个实现的话，就把

#include "TimeExt.h"

改为

#include <time.h>

然后在模块内部加入上面那两个常量数组就好了。

DS3231TimeHelper.c

/**********************************************************************************************DS3231 TIME HELPER MODULE** File : DS3231TimeHelper.c* By : Lin Shijun(/lin_strong)* Date: /09/26* version: V1.0* History: * note : the convert interfaces for DS3231 time.**********************************************************************************************/#include "DS3231TimeHelper.h"#include <stdint.h>#pragma MESSAGE DISABLE C2705#pragma MESSAGE DISABLE C12056void DS3231TimeToSystemTime(struct tm *dst, const TIME_STRUCT *src){uint16_t tmp;const int16_t * mdays;if(dst == NULL || src == NULL)return;dst->tm_sec = src->sec.sec_sd + src->sec.sec_td * 10;dst->tm_min = src->min.min_sd + src->min.min_td * 10;if(src->hour.SYS12.is12sys){tmp = src->hour.SYS12.hour_sd + src->hour.SYS12.hour_td * 10;tmp = (tmp == 12)? 0: tmp; // 12:30 am = 00:30(24h); 12:30pm = 12:30(24h)dst->tm_hour = (src->hour.SYS12.isPM)? tmp + 12: tmp;}else{dst->tm_hour = src->hour.SYS24.hour_sd + src->hour.SYS24.hour_td * 10;}dst->tm_mday = src->date.date_sd + src->date.date_td * 10;dst->tm_mon = src->cmon.mon_sd + src->cmon.mon_td * 10 - 1;dst->tm_year = src->year.year_sd + src->year.year_td * 10 + (DS3231_BASEYEAR - 1900) + src->cmon.century * 100;dst->tm_wday = src->day.day - 1;// treat TIME_STRUCT.day 1 as Sundayif(dst->tm_mon < 12){tmp = dst->tm_year + 1900;mdays = (IS_LEAP_YEAR(tmp))?TimeExt_lpdays: TimeExt_days;dst->tm_yday = mdays[dst->tm_mon] + dst->tm_mday;}dst->tm_isdst = 0;dst->tm_gmtoff = -1;}void SystemTimeToDS3231Time(TIME_STRUCT *dst, const struct tm *src){uint16_t tmp;if(dst == NULL || src == NULL)return;if(src->tm_year < (DS3231_BASEYEAR - 1900))return;dst->sec.sec_sd = src->tm_sec % 10;dst->sec.sec_td = src->tm_sec / 10;dst->min.min_sd = src->tm_min % 10;dst->min.min_td = src->tm_min / 10;dst->hour.SYS12.is12sys = 0; // use 24 hours systemdst->hour.SYS24.hour_sd = src->tm_hour % 10;dst->hour.SYS24.hour_td = src->tm_hour / 10;dst->date.date_sd = src->tm_mday % 10;dst->date.date_td = src->tm_mday / 10;dst->day.day = src->tm_wday + 1;tmp = src->tm_mon + 1;dst->cmon.mon_sd = tmp % 10;dst->cmon.mon_td = tmp / 10;tmp = src->tm_year - (DS3231_BASEYEAR - 1900);dst->cmon.century = tmp / 100 & 1;dst->year.year_sd = tmp % 10;tmp /= 10;dst->year.year_td = tmp % 10;}BOOL DS3231TimeValid(const TIME_STRUCT *time){uint16_t tmp;if(time == NULL)return FALSE;// BCD check(with some range check)if(time->sec.sec_sd > 9 || time->sec.sec_td > 5 ||time->min.min_sd > 9 || time->min.min_td > 5 ||time->hour.SYS24.hour_sd > 9 ||time->day.day == 0 ||time->date.date_sd > 9 ||time->cmon.mon_sd > 9 ||time->year.year_sd > 9 || time->year.year_td > 9)return FALSE;// range checkif(time->hour.SYS12.is12sys){tmp = time->hour.SYS12.hour_sd + time->hour.SYS12.hour_td * 10;if(tmp < 1 || tmp > 12)return FALSE;}else{tmp = time->hour.SYS24.hour_sd + time->hour.SYS24.hour_td * 10;if(tmp > 23)return FALSE;}tmp = time->cmon.mon_sd + time->cmon.mon_td * 10;if(tmp == 0 || tmp > 12)return FALSE;tmp = time->date.date_sd + time->date.date_td * 10;if(tmp == 0 || tmp > 31) // 其实更严格的检查的话得判断当前月份return FALSE;return TRUE;}

下面给出驱动代码的使用示例：

示例代码

#include <hidef.h>/* common defines and macros */#include "derivative.h"/* derivative-specific definitions */#include "DS3231Driver.h"#include "IIC.h"#include <stdio.h>typedef void (*near tIsrFunc)(void);const tIsrFunc _vect @0xFFC0 = IIC_ISR;#define BUS_CLOCK 32000000void Delay(void) {unsigned int i,j;for(i = 0; i < 100; i++)for(j = 0; j < 50000; j++);}void INIT_PLL(void) {CLKSEL &= 0x7f; //set OSCCLK as sysclkPLLCTL &= 0x8F; //DisaKble PLL circuitCRGINT &= 0xDF;#if(BUS_CLOCK == 40000000) SYNR = 0x44;#elif(BUS_CLOCK == 32000000)SYNR = 0x43;#elif(BUS_CLOCK == 24000000)SYNR = 0x42;#endif REFDV = 0x81; //PLLCLK=2×OSCCLK×(SYNR+1)/(REFDV+1)＝64MHz ,fbus=32MPLLCTL =PLLCTL|0x70; //Enable PLL circuitasm NOP;asm NOP;while(!(CRGFLG&0x08)); //PLLCLK is Locked alreadyCLKSEL |= 0x80; //set PLLCLK as sysclk}char strbuf[100];volatile TIME_STRUCT time;volatile TEMP_STRUCT temp;unsigned char* flag = (unsigned char*)0x3F80;void main(void) {// 5月11日星期五23点59分50秒time.year.year_td = 1; time.year.year_sd = 8;time.cmon.mon_td = 0; time.cmon.mon_sd = 5;time.date.date_td = 1; time.date.date_sd = 1;time.day.day = 5;time.hour.SYS24.is12sys = 0;time.hour.SYS24.hour_td = 2; time.hour.SYS24.hour_sd = 3;time.min.min_td = 5; time.min.min_sd = 9;time.sec.sec_td = 5; time.sec.sec_sd = 0;INIT_PLL();IIC_Init();DS3231_Init();EnableInterrupts;// 每次首次上电时设置当前时间if(*flag != 0xac){if(DS3231_SetTime(&time).errcode != DS3231_ERR_NULL)while(1);*flag = 0xac; // RAM中的数据在保持上电状态时即使系统重置也不会重置，但在上电重置时会重置}for(;;) {// 读取当前时间和温度，出任意错则无限循环停止运行if(DS3231_GetTime(&time).errcode != DS3231_ERR_NULL)while(1);if(DS3231_GetTemp(&temp).errcode != DS3231_ERR_NULL)while(1);sprintf(strbuf,"year:%d%d month:%d%d date:%d%d day:%d,%d%d:%d%d:%d%d\r\nTemp:%d.%02d\r\n",time.year.year_td,time.year.year_sd,time.cmon.mon_td,time.cmon.mon_sd,time.date.date_td,time.date.date_sd,time.day.day,time.hour.SYS24.hour_td,time.hour.SYS24.hour_sd,time.min.min_td,time.min.min_sd,time.sec.sec_td,time.sec.sec_sd,temp.integral.DATA,temp.fractional.DATA * 25);Delay();}}// 实现驱动要求的函数unsigned char IIC_ReadBurst(unsigned char calAddr,unsigned char *pBuf,unsigned short len){return IIC_Recv(calAddr,pBuf,len);}unsigned char IIC_SendBurst(unsigned char calAddr,unsigned char *pBuf,unsigned short len){return IIC_Send(calAddr,pBuf,len);}unsigned char IIC_ReadByte(unsigned char calAddr,unsigned char *rst){return IIC_RecvChar(calAddr,rst);}unsigned char IIC_SendByte(unsigned char calAddr,unsigned char val){return IIC_SendChar(calAddr,&val);}

测试结果

后记

这次对DS3231进行了简单的封装，难免会有不足或者错误之处，敬请指出。

测试中使用的IIC函数是自己封装的MC9S12XEP100的IIC模块，正在完善中，应该马上就会放出。

要求用户提供IIC函数是为了实现与硬件解耦，这样不管实际平台是怎么样的，用户只要按照要求实现IIC通讯函数就可以使用这个驱动了。

简介中完全参考Maxim的数据手册。

注意

结构体位字段的写法有移植性问题，和编译器怎么排布位域有关。要检查有没问题的话，比如设

time.year.year_td = 1; time.year.year_sd = 8;

然后调试器看下内存，对应字节应该为0x18。如果是0x81的话，需要把结构体定义中的所有位字段的位置都掉个个。

另外，还可能遇到结构体对齐特性上的移植性问题。TIME_STRUCT中的每个寄存器结构体都应该占1个byte，也就是说sizeof(TIME_STRUCT)应该等于7，sizeof(REG_SEC)应该等于1。

目前已知stm32的编译器对位域上会根据类型声明来对齐，因此对于stm32的话应该把所有的位域的类型改成unsigned char，如REG_SEC应该改成这样：

typedef struct {unsigned char sec_sd: 4; // ones digit of second 秒的个位unsigned char sec_td: 3; // tens digit of second 秒的十位unsigned char : 1;} REG_SEC;

这是stm32编译器自己的扩展，非语言本身规范。

更新历史

/05/14

/10/18 增加时间转换助手模块