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Application: Real-Time Clock on LCD (rtc_on_lcd.c)

rtc_on_lcd.c

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/*******************************************************************************
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 * Filename     : rtc_on_lcd.c
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 * Description  : Application to read time and date information from DS1207 RTC
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 *                chip and display it on the 16x2 Character LCD
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 * Author       : Kyungjae Lee
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 * History      : Jun 25, 2023 - Created file
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 ******************************************************************************/
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#include <lcd_hd44780u.h>
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#include "rtc_ds1307.h"
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#include <string.h>         /* strlen() */
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#include <stdio.h>          /* printf() */
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#include "stm32f407xx.h"
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#define SYSTICK_TIM_CLK     16000000UL
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/* SysTick timer registers */
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#define SYST_CSR            (*(uint32_t volatile *)0xE000E010)
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#define SYST_RVR            (*(uint32_t volatile *)0xE000E014)
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/* SysTick Control and Status Register (SYST_CSR) bit fields */
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#define SYST_CSR_ENABLE     (1 << 0U) /* Counter enabled */
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#define SYST_CSR_TICKINT    (1 << 1U)
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#define SYST_CSR_CLKSOURCE  (1 << 2U) /* Processor clock */
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#define PRINT_ON_LCD    /* Comment this out if LCD is not installed */
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/* Function prototypes */
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void DisplayPrologue(void);
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char* TimeToString(RTC_Time_TypeDef *rtcTime);
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char* DateToString(RTC_Date_TypeDef *rtcDate);
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char* GetDay(uint8_t dayCode);
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void NumToString(uint8_t num, char *buf);
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void SysTickTimer_Init(uint32_t tickHz);
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void DelayMs(uint32_t delayInMs);
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int main(int argc, char *argv[])
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{
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    RTC_Time_TypeDef currTime;
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    RTC_Date_TypeDef currDate;
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    char *amPm;
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    printf("Application running with LCD...\n");
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#ifndef PRINT_ON_LCD
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    printf("Application running without LCD...\n");
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#else
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    /* Initialize LCD module */
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    LCD_Init();
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    /* Display the project title and the name of the author */
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    DisplayPrologue();
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#endif
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    /* Initialize Tiny RTC module */
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    if (DS1307_Init())
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    {
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        /* RTC initialization was unsuccessful */
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        printf("RTC init failed\n");
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        while (1);
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    }
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    /* Initialize the SysTick Timer so it generates 1 interrupt per second */
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    SysTickTimer_Init(1);
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    /* Configure initial date and time to set */
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    currDate.day = FRIDAY;
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    currDate.date = 14;
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    currDate.month = 7;
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    currDate.year = 23;     /* Only the last two digits of the year */
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    currTime.hours = 11;
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    currTime.minutes = 59;
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    currTime.seconds = 50;
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    currTime.timeFormat = TIME_FORMAT_12HRS_PM;
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    /* Set initial time and date */
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    DS1307_SetCurrentDate(&currDate);
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    DS1307_SetCurrentTime(&currTime);
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    /* Get initial time and date */
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    DS1307_GetCurrentDate(&currDate);
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    DS1307_GetCurrentTime(&currTime);
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    /* Print current time ----------------------------------------------------*/
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    if (currTime.timeFormat != TIME_FORMAT_24HRS)
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    {
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        /* 12HRS format (e.g., 08:33:45 PM) */
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        amPm = (currTime.timeFormat) ? "PM" : "AM";
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#ifndef PRINT_ON_LCD
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        printf("Current time = %s %s\n", TimeToString(&currTime), amPm);
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#else
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        LCD_SetCursor(2, 1);
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        LCD_PrintString(TimeToString(&currTime));
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        LCD_PrintString(" ");
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        LCD_PrintString(amPm);
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#endif
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    }
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    else
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    {
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        /* 24HRS format (e.g., 20:33:45) */
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#ifndef PRINT_ON_LCD
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        printf("Current time = %s\n", TimeToString(&currTime));
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#else
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        LCD_PrintString(TimeToString(&currTime));
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#endif
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    }
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    /* Print current date in 'MM/DD/YY Day' format ---------------------------*/
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#ifndef PRINT_ON_LCD
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    printf("Current date = %s %s\n", DateToString(&currDate), GetDay(currDate.day));
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#else
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    LCD_SetCursor(1, 1);
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    LCD_PrintString(DateToString(&currDate));
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    LCD_PrintString(" ");
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    LCD_PrintString(GetDay(currDate.day));
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#endif
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    while (1);
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    return 0;
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} /* End of main */
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/**
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 * DisplayPrologue()
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 * Desc.    : Displays the project title and the author's name
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 * Param.   : None
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 * Returns  : None
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 * Note     : N/A
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 */
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void DisplayPrologue(void)
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{
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    /* Display the project title */
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    LCD_PrintString("Real-time clock");
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    LCD_SetCursor(2, 1);
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    LCD_PrintString("on 16x2 LCD");
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    /* Introduce inter-frame delay */
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    DelayMs(3000);
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    /* Clear display */
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    LCD_ClearDisplay();
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    LCD_ReturnHome();
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    /* Display the author's name */
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    LCD_PrintString("by");
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    LCD_SetCursor(2, 1);
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    LCD_PrintString("Kyungjae Lee");
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    DelayMs(3000);
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    /* Clear display */
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    LCD_ClearDisplay();
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    LCD_ReturnHome();
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} /* End of DisplayPrologue */
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/**
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 * TimeToString()
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 * Desc.    : Converts the time represented by @rtcTime to a string
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 * Param.   : @rtcTime - pointer to RTC Time structure
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 * Return   : Time in string format (e.g., HH:MM:SS PM)
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 * Note     : N/A
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 */
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char* TimeToString(RTC_Time_TypeDef *rtcTime)
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{
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    static char buf[9]; /* Make it static not to return a dangling ptr */
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    buf[2] = ':';
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    buf[5] = ':';
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    NumToString(rtcTime->hours, buf);
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    NumToString(rtcTime->minutes, &buf[3]);
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    NumToString(rtcTime->seconds, &buf[6]);
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    buf[8] = '\0';
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    return buf;
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} /* End of TimeToString */
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/**
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 * DateToString()
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 * Desc.    : Converts the date represented by @rtcDate to a string
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 * Param.   : @rtcDate - pointer to RTC Date structure
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 * Return   : Date in string format (e.g., MM/DD/YY <Day>)
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 * Note     : N/A
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 */
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char* DateToString(RTC_Date_TypeDef *rtcDate)
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{
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    static char buf[9]; /* Make it static not to return a dangling ptr */
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    buf[2] = '/';
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    buf[5] = '/';
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    NumToString(rtcDate->month, buf);
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    NumToString(rtcDate->date, &buf[3]);
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    NumToString(rtcDate->year, &buf[6]);
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    buf[8] = '\0';
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    return buf;
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} /* End of DateToString */
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/**
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 * GetDay()
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 * Desc.    : Gets the day represented by @dayCode in string format
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 * Param.   : @dayCode - day macro
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 * Return   : Day in string format (e.g., Sunday)
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 * Note     : N/A
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 */
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char* GetDay(uint8_t dayCode)
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{
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    char *days[] = {"SUN", "MON", "TUE", "WED", "THU", "FRI", "SAT"};
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    return days[dayCode];
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} /* End of GetDay */
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/**
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 * NumToString()
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 * Desc.    : Converts the passed uint8_t number @num and store it into @buf
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 * Param.   : @num - a number to be converted into a string
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 *            @buf - pointer to a string buffer
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 * Return   : None
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 * Note     : N/A
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 */
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void NumToString(uint8_t num, char *buf)
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{
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    if (num < 10)
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    {
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        buf[0] = '0';
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        buf[1] = num + '0';
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        //buf[1] = num + 48;
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    }
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    else if (10 <= num && num < 99)
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    {
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        buf[0] = num / 10 + '0';
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        buf[1] = num % 10 + '0';
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        //buf[0] = num / 10 + 48;
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        //buf[1] = num % 10 + 48;
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    }
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} /* End of NumToString */
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/**
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 * SysTickTimer_Init()
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 * Desc.    : Initializes the SysTick Timer
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 * Param.   : @tickHz - number of interrupts to be triggered per second
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 * Return   : None
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 * Note     : Counting down to zero asserts the SysTick exception request.
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 */
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void SysTickTimer_Init(uint32_t tickHz)
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{
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    /* Calculate reload value */
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    uint32_t reloadVal = (SYSTICK_TIM_CLK / tickHz) - 1;
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    /* Clear the least significant 24 bits in the SYST_RVR */
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    SYST_RVR &= ~0x00FFFFFF;
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    /* Load the counter start value into SYST_RVR */
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    SYST_RVR |= reloadVal;
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    /* Configure SYST_CSR */
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    SYST_CSR |= (SYST_CSR_TICKINT | SYST_CSR_CLKSOURCE | SYST_CSR_ENABLE);
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        /* TICKINT  : Enable SysTick exception request */
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        /* CLKSOURCE: Specify clock source; processor clock source */
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        /* ENABLE   : Enable counter */
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} /* End of SysTickTimer_Init */
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/**
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 * SysTick_Handler()
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 * Desc.    : Handles the SysTick exception
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 * Param.   : None
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 * Return   : None
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 * Note     : N/A
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 */
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void SysTick_Handler(void)
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{
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    RTC_Time_TypeDef currTime;
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    RTC_Date_TypeDef currDate;
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    char *amPm;
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    /* Print current time ----------------------------------------------------*/
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    DS1307_GetCurrentTime(&currTime);
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    if (currTime.timeFormat != TIME_FORMAT_24HRS)
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    {
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        /* 12HRS format (e.g., 08:33:45 PM) */
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        amPm = (currTime.timeFormat) ? "PM" : "AM";
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#ifndef PRINT_ON_LCD
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        printf("Current time = %s %s\n", TimeToString(&currTime), amPm);
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#else
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        LCD_SetCursor(2, 1);
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        LCD_PrintString(TimeToString(&currTime));
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        LCD_PrintString(" ");
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        LCD_PrintString(amPm);
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#endif
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    }
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    else
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    {
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        /* 24HRS format (e.g., 20:33:45) */
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#ifndef PRINT_ON_LCD
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        printf("Current time = %s\n", TimeToString(&currTime));
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#else
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        LCD_SetCursor(2, 1);
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        LCD_PrintString(TimeToString(&currTime));
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#endif
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    }
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    /* Print current date in 'MM/DD/YY Day' format ---------------------------*/
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    DS1307_GetCurrentDate(&currDate);
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#ifndef PRINT_ON_LCD
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    printf("Current date = %s <%s>\n", DateToString(&currDate), GetDay(currDate.day));
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#else
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    LCD_SetCursor(1, 1);
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    LCD_PrintString(DateToString(&currDate));
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    LCD_PrintString(" ");
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    //LCD_PrintChar('<');
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    LCD_PrintString(GetDay(currDate.day));
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    //LCD_PrintChar('>');
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#endif
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} /* End of SysTick_Handler */
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/**
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 * DelayMs()
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 * Desc.    : Spinlock delays for @delayInMs milliseconds
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 * Param.   : @delayInMs - time to delay in milliseconds
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 * Returns  : None
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 * Note     : N/A
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 */
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void DelayMs(uint32_t delayInMs)
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{
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    for (uint32_t i = 0; i < delayInMs * 1000; i++);
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} /* End of DelayMs */