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507 kaklik 1 
/*--------------------------------------------------------------------------*/
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/*  RTC controls                                                            */
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#include <avr/io.h>
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#include <string.h>
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#include "rtc.h"
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#define SCL_LOW()	DDRE |=	0x04			/* SCL = LOW */
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#define SCL_HIGH()	DDRE &=	0xFB			/* SCL = High-Z */
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#define	SCL_VAL		((PINE & 0x04) ? 1 : 0)	/* SCL input level */
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#define SDA_LOW()	DDRE |=	0x08			/* SDA = LOW */
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#define SDA_HIGH()	DDRE &=	0xF7			/* SDA = High-Z */
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#define	SDA_VAL		((PINE & 0x08) ? 1 : 0)	/* SDA input level */
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static
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void iic_delay (void)
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{
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	int n;
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	BYTE d;
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	for (n = 4; n; n--) d = PINE;
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}
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/* Generate start condition on the IIC bus */
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static
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void iic_start (void)
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{
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	SDA_HIGH();
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	iic_delay();
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	SCL_HIGH();
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	iic_delay();
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	SDA_LOW();
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	iic_delay();
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	SCL_LOW();
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	iic_delay();
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}
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/* Generate stop condition on the IIC bus */
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static
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void iic_stop (void)
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{
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	SDA_LOW();
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	iic_delay();
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	SCL_HIGH();
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	iic_delay();
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	SDA_HIGH();
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	iic_delay();
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}
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/* Send a byte to the IIC bus */
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static
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BOOL iic_send (BYTE dat)
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{
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	BYTE b = 0x80;
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	BOOL ack;
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	do {
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		if (dat & b)	 {	/* SDA = Z/L */
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			SDA_HIGH();
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		} else {
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			SDA_LOW();
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		}
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		iic_delay();
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		SCL_HIGH();
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		iic_delay();
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		SCL_LOW();
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		iic_delay();
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	} while (b >>= 1);
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	SDA_HIGH();
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	iic_delay();
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	SCL_HIGH();
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	ack = SDA_VAL ? FALSE : TRUE;	/* Sample ACK */
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	iic_delay();
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	SCL_LOW();
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	iic_delay();
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	return ack;
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}
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/* Receive a byte from the IIC bus */
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static
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BYTE iic_rcvr (BOOL ack)
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{
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	UINT d = 1;
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	do {
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		d <<= 1;
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		SCL_HIGH();
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		if (SDA_VAL) d++;
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		iic_delay();
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		SCL_LOW();
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		iic_delay();
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	} while (d < 0x100);
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	if (ack) {		/* SDA = ACK */
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		SDA_LOW();
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	} else {
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		SDA_HIGH();
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	}
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	iic_delay();
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	SCL_HIGH();
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	iic_delay();
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	SCL_LOW();
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	SDA_HIGH();
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	iic_delay();
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	return (BYTE)d;
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}
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BOOL rtc_read (
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	UINT adr,		/* Read start address */
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	UINT cnt,		/* Read byte count */
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	void* buff		/* Read data buffer */
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)
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{
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	BYTE *rbuff = buff;
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	int n;
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	if (!cnt) return FALSE;
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	n = 10;
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	do {							/* Select DS1338 (0xD0) */
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		iic_start();
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	} while (!iic_send(0xD0) && --n);
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	if (!n) return FALSE;
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	if (iic_send((BYTE)adr)) {		/* Set start address */
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		iic_start();				/* Reselect DS1338 in read mode (0xD1) */
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		if (iic_send(0xD1)) {
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			do {					/* Receive data */
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				cnt--;
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				*rbuff++ = iic_rcvr(cnt ? TRUE : FALSE);
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			} while (cnt);
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		}
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	}
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	iic_stop();						/* Deselect device */
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	return cnt ? FALSE : TRUE;
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}
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BOOL rtc_write (
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	UINT adr,			/* Write start address */
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	UINT cnt,			/* Write byte count */
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	const void* buff	/* Data to be written */
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)
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{
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	const BYTE *wbuff = buff;
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	int n;
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	if (!cnt) return FALSE;
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	n = 10;
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	do {							/* Select DS1338 (0xD0) */
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		iic_start();
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	} while (!iic_send(0xD0) && --n);
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	if (!n) return FALSE;
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	if (iic_send((BYTE)adr)) {		/* Set start address */
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		do {						/* Send data */
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			if (!iic_send(*wbuff++)) break;
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		} while (--cnt);
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	}
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	iic_stop();						/* Deselect device */
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	return cnt ? FALSE : TRUE;
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}
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BOOL rtc_gettime (RTC *rtc)
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{
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	BYTE buf[8];
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	if (!rtc_read(0, 7, buf)) return FALSE;
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	rtc->sec = (buf[0] & 0x0F) + ((buf[0] >> 4) & 7) * 10;
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	rtc->min = (buf[1] & 0x0F) + (buf[1] >> 4) * 10;
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	rtc->hour = (buf[2] & 0x0F) + ((buf[2] >> 4) & 3) * 10;
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	rtc->mday = (buf[4] & 0x0F) + ((buf[4] >> 4) & 3) * 10;
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	rtc->month = (buf[5] & 0x0F) + ((buf[5] >> 4) & 1) * 10;
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	rtc->year = 2000 + (buf[6] & 0x0F) + (buf[6] >> 4) * 10;
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	return TRUE;
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}
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BOOL rtc_settime (const RTC *rtc)
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{
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	BYTE buf[8];
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	buf[0] = rtc->sec / 10 * 16 + rtc->sec % 10;
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	buf[1] = rtc->min / 10 * 16 + rtc->min % 10;
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	buf[2] = rtc->hour / 10 * 16 + rtc->hour % 10;
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	buf[3] = 0;
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	buf[4] = rtc->mday / 10 * 16 + rtc->mday % 10;
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	buf[5] = rtc->month / 10 * 16 + rtc->month % 10;
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	buf[6] = (rtc->year - 2000) / 10 * 16 + (rtc->year - 2000) % 10;
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	rtc_write(0, 7, buf);
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	return TRUE;
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}
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BOOL rtc_init (void)
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{
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	BYTE buf[8];	/* RTC R/W buffer */
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	UINT n;
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	/* Read RTC registers */
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	if (!rtc_read(0, 8, buf)) return FALSE;	/* IIC error */
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	if (buf[7] & 0x20) {	/* When RTC data has been broken, set default time */
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		/* Reset time to Jan 1, '08 */
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		memset(buf, 0, 8);
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		buf[4] = 1; buf[5] = 1; buf[6] = 8;
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		rtc_write(0, 8, buf);
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		/* Clear data memory */
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		memset(buf, 0, 8);
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		for (n = 8; n < 64; n += 8)
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			rtc_write(n, 8, buf);
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		return FALSE;
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	}
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	return TRUE;
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}
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