Figure 3. Program Listing /*********************************************************************/
/* Ds1318AN.c program, use on the DS1318 app note board              */
/*********************************************************************/
#include <stdio.h>		/* Prototypes for I/O functions           */
#include <DS5000.h>		/* Register declarations for DS5000       */
#include <absacc.h>		/* needed to define xdata addresses       */
/***************************** Defines *******************************/
#define SSEC1	XBYTE[0x0000]
#define SSEC2	XBYTE[0x0001]
#define SEC0	XBYTE[0x0002]
#define SEC1	XBYTE[0x0003]
#define SEC2	XBYTE[0x0004]
#define SEC3	XBYTE[0x0005]
#define AL0	XBYTE[0x0006]
#define AL1	XBYTE[0x0007]
#define AL2	XBYTE[0x0008]
#define AL3	XBYTE[0x0009]
#define CTLA	XBYTE[0x000A]
#define CTLB	XBYTE[0x000B]
#define STAT	XBYTE[0x000C]
/************************* bit definitions ***************************/
/************************* Global Variables **************************/
uchar	int_flg = 0;
/*********************** Function Prototypes *************************/
void	init_rtc();
void	writebyte();
void	readregs();
void	disp_clk_regs();
void	disp_clk_regs_int();
void	bin2date();
unsigned long	date2bin(uint, uint, uint, uint, uint, uint);
void	external0_int(void);

void init_rtc()	/* ------------ set the time and date ----------------- */
/* Note: NO error checking is done on the user entries! */
{
uint	yrs, mon, dt, hrs, min, sec;
unsigned long y;

	printf("\nEnter the year (1970-2099): ");
	scanf("%d", &yrs);
	printf("Enter the month (1-12): ");
	scanf("%d", &mon);
	printf("Enter the date (1-31): ");
	scanf("%d", &dt);
	printf("Enter the hour (0-23): ");
	scanf("%d", &hrs);
	printf("Enter the minute (0-59): ");
	scanf("%d", &min);
	printf("Enter the second (0-59): ");
	scanf("%d", &sec);

	CTLA = 0x46;	/* disable update transfers */

	y = date2bin(yrs, mon, dt, hrs, min, sec);

	SEC0 = (y & 0xff);
	SEC1 = ((y >> 8) & 0xff);
	SEC2 = ((y >> 16) & 0xff);
	SEC3 = ((y >> 24) & 0xff);

	CTLA = 0xC6;
}
void	writebyte()	/* -------- enter data for one byte --------- */
{
int	add;
uchar	dat;

	printf("\nEnter address (hex): ");
	scanf("%x", &add);

	printf("Enter data (hex): ");
	scanf("%bx", &dat);

	XBYTE[add] = dat;
}
void	readregs()	/* --------- list all of the registers -------- */
{
uchar	inc;

	CTLA = 0x46;	/* disable update transfers */

	printf("\n");
	for(inc = 0; inc < 0xd; inc++)
	{
		printf("%02bx ", XBYTE[inc]);
	}

	CTLA = 0xC6;	/* enable transfers, osc, sqw */
}
void disp_clk_regs()		/* -------------- read time & date using TE as intended ----------------- */
{
uchar prv_sec = 99;

	while(!RI)	/* Read & Display Clock Registers */
	{
		if(prv_sec != SEC0)	/* display once per second */
		{
			bin2date();
			prv_sec = SEC0;
		}
	}
		RI = 0;  /* Swallow keypress to exit loop */
}
void disp_clk_regs_int()		/* ----- display time using irq output ----- */
{
	CTLA = 0xC6;	/* enable update transfers, oscillator, squarewave and PIE */
	CTLB = 0xA0;	/* PF = 1Hz, SQW = 32kHz */

	EX0 = 1;	/* enable interrupt 0 */
	IT0 = 1;	/* edge activated */
	PX0 = 0;	/* low priority */
	EX1 = 0;	/* disable interrupt 1 */
	EA = 1;	/* enable all interrupts */

	while(!RI)	/* Read & Display Clock Registers */
	{
		while(!int_flg);	/* wait for interrupt */

		if(int_flg & 0x02)	/* only display if the periodic flag caused the interrupt */
		{
			EX0 = EX1 = 0;	/* disable interrupts while updating the display */

			bin2date();		/* calculate and display time and date */

			int_flg = 0;		/* for this example, we'll just clear all interrupt sources */
			EX0 = EX1 = 1;	/* re-enable interrupts */
		}
	}
	EX0 = 0;		/* disable interrupt */
	RI = 0;  		/* Swallow keypress to exit loop */
}
/* Note: The following routine could be replaced with the ANSI C ctime function */
void bin2date()	/* ------ convert binary time to date format ------ */
{
int	yrs, mon, day, date, dow, tmp, jday, hrs, min, sec;
uchar	ssec;
unsigned long x, j, n;

	CTLA = 0x46;	/* disable update transfers */

	x = SEC3;
	x <<= 8;
	x |= SEC2;
	x <<= 8;
	x |= SEC1;
	x <<= 8;
	x |= SEC0;
	ssec = SSEC2;

	CTLA = 0xC6;	/* enable transfers, osc, sqw */

	j = x / 60;			/* whole minutes since 1/1/70 */
	sec = x - (60 * j);		/* leftover seconds */
	n = j / 60;
	min = j - (60 * n);
	j = n / 24;
	hrs = n - (24 * j);

	j = j + (365 + 366);		/* whole days since 1/1/68 */
	day = j / ((4 * 365) + 1);
	tmp = j % ((4 * 365) + 1);

	if(tmp >= (31 + 29))		/* if past 2/29 */
		day++;			/* add a leap day */

	yrs = (j - day) / 365;		/* whole years since 1968 */
	jday = j - (yrs * 365) - day;	/* days since 1/1 of current year */
	if(tmp <= 365 && tmp >= 60)		/* if past 2/29 and a leap year then */
		jday++;			/* add a leap day */
	yrs += 1968;				/* calculate year */

	for(mon = 12; mon > 0; mon--)
	{
		switch(mon)
		{
			case 1:	tmp = 0;	break;
			case 2:	tmp = 31;	break;
			case 3:	tmp = 59;	break;
			case 4:	tmp = 90;	break;
			case 5:	tmp = 120;	break;
			case 6:	tmp = 151;	break;
			case 7:	tmp = 181;	break;
			case 8:	tmp = 212;	break;
			case 9:	tmp = 243;	break;
			case 10:	tmp = 273;	break;
			case 11:	tmp = 304;	break;
			case 12:	tmp = 334;	break;
		}
		if((mon > 2) && !(yrs % 4))	/* adjust for leap year */
			tmp++;
		if(jday >= tmp)	break;
	}
	day = jday - tmp + 1;	/* calculate day in month */
	dow = (j + 1) % 7 + 1;	/* 1 = Sun, 2 = Mon, and so on */

	printf("\n%04d/%02d/%02d %d %02d:%02d:", yrs ,mon, day, dow, hrs, min);
	printf("%02d.%02bu", sec, ssec);
}
/* ---- convert date to elapsed days in binary ---- */
unsigned long	date2bin(uint yrs, uint mon, uint day, uint hrs, uint min, uint sec)
{
unsigned long x;

	/* the following is broken down for clarity */
	x = 365 * (yrs - 1970);			/* calculate number of days for previous years */
	x += (yrs - 1969) >> 2;			/* add a day for each leap year */
	if((mon > 2) && (yrs % 4 == 0))		/* add a day if current year is leap and past Feb 29th */
		x++;

	switch(mon)
	{
		case 1:	x += 0;	break;
		case 2:	x += 31;	break;
		case 3:	x += 59;	break;
		case 4:	x += 90;	break;
		case 5:	x += 120;	break;
		case 6:	x += 151;	break;
		case 7:	x += 181;	break;
		case 8:	x += 212;	break;
		case 9:	x += 243;	break;
		case 10:	x += 273;	break;
		case 11:	x += 304;	break;
		case 12:	x += 334;	break;
	}

	x += day - 1;			/* finally, add the days into the current month */
	x = x * 86400;		/* and calculate the number of seconds in all those days */
	x += ((long) hrs * 3600);	/* add the number of seconds in the hours */
	x += (min * 60);		/* ditto the minutes */
	x += sec;			/* finally, the seconds */
	return(x);
}
void	external0_int(void) interrupt 0	/* --- display time/date on interrupt from RTC --- */
{
	EX0 = EX1 = 0;	/* disable interrupt */
	int_flg = STAT;	/* clear the interrupt source, save the info */
	STAT = 0;		/* clear PF (and all other bits) */
	EX0 = EX1 = 1;	/* re-enable interrupt */
}
main (void)		/* ----------------------------------------------------- */
{
uchar i, M, M1;

	while (1)
	{
	printf("\nDS1318  build %s\n", __DATE__);
	printf("CI Clock Init CN Clk iNt rd\n");
	printf("CR Read Time   W Write byte\n");
	printf("R  Read regs\n");
	printf("Enter Menu Selection:");

	M = _getkey();

	switch(M) 
	{
		case 'C':
		case 'c':
		printf("\rEnter Clock Routine to run: C");
		M1 = _getkey();

		switch(M1) 
		{
			case 'I':
			case 'i':	init_rtc();	break;

			case 'N':
			case 'n':	disp_clk_regs_int();	break;

			case 'R':
			case 'r':	disp_clk_regs();	break;
		}
		break;

		case 'R':
		case 'r':	readregs();	break;

		case 'W':
		case 'w':	writebyte();	break;
	}
   }
}