/*
*****************************************************************************
*
* File Name - rtc_read.c
* Function - Demonstrates reading from the uFlash RTC over the I2C connection
*
* Note that you should run the rtc_set program to set and enable the RTC
* before using this program
*
* You will need:
* (1) uFlash & CCS PIC C compiler (PCM/PCW)
* (2) PC Terminal emulator (such as Hyperterm)
*
* Instructions:
* (1) Compile & downloading to the uFlash
* (2) Setup Hyprterm for 57K6 Baud,8 bits, no parity, no echo, no handshaking
* (3) Remove the Pgrm Jumper from the uFlash (this stops Hyperterm from
* holding the uFlash in reset).
* (4) Run Hyperterm
*
*	Since there is no logical difference between an I2C chip located on the
*	internal I2C bus of a uFlash and one located on the uConnect bus of a
*	uFlash876B, we can use the uConnect library code to simplify access to
*	the RTC. This means that this code would also work for a uFlash876B with
*	an RTC located externally on the uConnect bus.
*
*****************************************************************************
*/

#include <uF876.h>
#include <uConn.h>			// use the uConnect support code
/*
******************************* rtc buffer locations ************************
*/

#define SEC		0			// RTC data offsets in the buffer
#define MIN		1			// note that RTC data is stored in
#define HOUR 	2			// Binary Coded Decimal (BCD) format
#define DOW		3
#define DAY		4
#define MONTH	5
#define YEAR	6

/*
******************************* rtc buffer **********************************
*
*	This RAM buffer mirrors the format of the RTC on chip registers
*	All values are stored in Binary Coded Decimal (BCD)
*	See DS1307 data sheet for details
*
*	The initial value shown here is 00:00:00 Saturday 01/01/2000
*/

BYTE rtc[7]=
	{
	0x00,					// Seconds (0-59)  (Bit 7 is the enable flag)
	0x00,					// Minutes (0-59)
	0x00,					// Hours (0-24 or 0-12 am/pm) (Bit 6 12/24 hr ctrl)
	0x07,					// Day of week (1-7)
	0x01,					// Day of month (1-31)
	0x01,					// Month (1-12)
	0x00					// Year (0-99)
	};

/*
***************************** function prototypes ***************************
*/
void read_rtc(void);
void print_rtc(void);

/*
*********************************** main ************************************
*
*	Read and display the date & time each time it changes
*/

void main(void)
	{
	BYTE last_sec;					// the last second read from the rtc

	printf("RTC Read - Reads and displays the contents of the uFlash RTC\r");
	printf("If the the data displayed is wrong or invalid please use the\r");
	printf("rtc_set program to set the uFlash RTC to a valid time\r\r");

	last_sec=0xff;					// force print_rtc to run next time

	while(true)						// loop forever
		{
		delay_ms(100);				// every 100 mS
		read_rtc();					// read the rtc
		if(last_sec!=rtc[0])		// if the time has changed
			{
			last_sec=rtc[0];		// update last_sec
			print_rtc();			// print the date & time
			}
		}
	}

/*
****************************** read_rtc *************************************
*
*	Copy the contents of the rtc chip to the rtc buffer
*
*	Not used in the rtc_set program
*/
void read_rtc(void)
	{
	uc_wstart(0x68);			// address the RTC (write)
	uc_write(0);				// start at location 0 (SEC)
	uc_rstart(0x68);			// address the RTC (read)
	rtc[SEC]=uc_read(1);		// read seconds
	rtc[MIN]=uc_read(1);		// read minutes
	rtc[HOUR]=uc_read(1);		// read hours
	rtc[DOW]=uc_read(1);		// read day of week
	rtc[DAY]=uc_read(1);		// read day of month
	rtc[MONTH]=uc_read(1);		// read month
	rtc[YEAR]=uc_read(0);		// read year (since 2000)
	uc_stop();					// finished
	}
	

/*
**************************** print_rtc **************************************
*
*	Print the contents of the rtc buffer
*	Note that because RTC values are stored in BCD format printing them in
*	hex gives the required result (think about it!)
*
*	Display format is:
*
*	hh:mm:ss dayofweek dd/mm/yyyy
*/
void print_rtc(void)
	{
	printf("%02x:%02x:%02x ",rtc[HOUR],rtc[MIN],rtc[SEC]);

	switch(rtc[DOW])
		{
		case 1:
			printf("Sunday ");
			break;
		case 2:
			printf("Monday ");
			break;
		case 3:
			printf("Tuesday ");
			break;
		case 4:
			printf("Wednesday ");
			break;
		case 5:
			printf("Thursday ");
			break;
		case 6:
			printf("Friday ");
			break;
		case 7:
			printf("Saturday ");
			break;
		}
	printf("%02x/%02x/%04lx\r",rtc[DAY],rtc[MONTH],rtc[YEAR]+0x2000);
	}