avrreadeeprom.c

利用GCCAVR读写EEPROM源代码

#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>

#include <avr/io.h>
#include <util/twi.h>       
#include <util/delay.h>
#include <avr/interrupt.h>

#define DEBUG 1
#define F_CPU 14745600UL    


#ifndef UCSRB
# ifdef UCSR1A      /* ATmega128 */
#  define UCSRA UCSR1A
#  define UCSRB UCSR1B
#  define UBRR UBRR1L
#  define UDR UDR1
# else /* ATmega8 */
#  define UCSRA USR
#  define UCSRB UCR
# endif
#endif
#ifndef UBRR
#  define UBRR UBRRL
#endif


#define TWI_SLA_24CXX   0xa2 


#define MAX_ITER    200


#define PAGE_SIZE 8

uint8_t twst;
unsigned char k;

ioinit(void)
{
	
#if F_CPU <= 1000000UL
	
	UCSRA = _BV(U2X);
	UBRR = (F_CPU / (8 * 9600UL)) - 1; /* 9600 Bd */
#else
	UBRR = (F_CPU / (16 * 9600UL)) - 1; /* 9600 Bd */
#endif
	UCSRB = _BV(TXEN);        /* tx enable */
	
	/* initialize TWI clock: 100 kHz clock, TWPS = 0 => prescaler = 1 */
#if defined(TWPS0)
	/* has prescaler (mega128 & newer) */
	TWSR = 0;
#endif
	
#if F_CPU < 3600000UL
	TWBR = 10;            /* smallest TWBR value*/
#else
	TWBR = (F_CPU / 100000UL - 16) / 2;
#endif
}

/*
* Send character c down the UART Tx, wait until tx holding register
* is empty.
*/
int uart_putchar(char c, FILE *unused)
{
	
	if (c == '\n')
		uart_putchar('\r', 0);
	loop_until_bit_is_set(UCSRA, UDRE);
	UDR = c;
	return 0;
}

void delay(unsigned int ms)
{
	_delay_ms(ms);
	
}
 
int IICRead_Byte( uint16_t eeaddr, int len, uint8_t *buf)
{
	uint8_t sla, twcr, n = 0;
	int rv = 0;
	
 

	/*high byte of eeprom*/
	sla =TWI_SLA_24CXX| (((eeaddr >> 8) & 0x07) << 1);
	
	 
	
	
restart:
	if (n++ >= MAX_ITER)/* error limte*/
		return -1;
	/*******************************************/
	
	/* master transmitter mode	*/
begin:
	
	TWCR = _BV(TWINT) | _BV(TWSTA) | _BV(TWEN); /* send start condition */
	while ((TWCR & _BV(TWINT)) == 0) ; 
	
	twst=TW_STATUS;
	if( twst!= TW_START)
		
	{
		return -1;
	}	
	
    delay(5);
	
	
	
	
	/* send SLA+W */
	TWDR = sla | TW_WRITE;
	TWCR = _BV(TWINT) | _BV(TWEN); /* start transmission */
	while ((TWCR & _BV(TWINT)) == 0) ; /* wait for transmission */
	
	twst=TW_STATUS;
	if(twst!=TW_MT_SLA_ACK)
	{
		
		return -1;
	}
	
	
	delay(10);


	TWDR = eeaddr;        /* low 8 bits of addr */
	TWCR = _BV(TWINT) | _BV(TWEN); /* start transmission */
	while ((TWCR & _BV(TWINT)) == 0) ; /* wait for transmission */
	
	twst=TW_STATUS;
	if(twst!=TW_MT_DATA_ACK)
	{
		 
		return -1;
	}
	
	delay(10);
	
	
	/*	* master receiver mode*/
	
	
	TWCR = _BV(TWINT) | _BV(TWSTA) | _BV(TWEN); /* rstart condition */
	while ((TWCR & _BV(TWINT)) == 0) ; /* wait for transmission */
	
	twst=TW_STATUS;
	if(twst!=TW_REP_START)
	{
		TWCR = _BV(TWINT) | _BV(TWSTO) | _BV(TWEN); /* send stop condition */
		goto restart;
		return -1;		
	}
	
	PORTB=0X7F;
	
	delay(10);

	/* send SLA+R */
	
	
	TWDR =sla| TW_READ;
	
	/*TWDR= 1;*/
	TWCR = _BV(TWINT) | _BV(TWEN); /* clear interrupt to start transmission */
	delay(10);

	while ((TWCR & _BV(TWINT)) == 0) ; /* wait for transmission */
	_delay_us(1);
	//TWCR=_BV(TWEA);
	twst=TW_STATUS;
	PORTB=0XBF;
	if(twst!=TW_MR_SLA_ACK)
	{
		
	  
		return -1;
		
		
	}
	

	for (twcr = _BV(TWINT) | _BV(TWEN) | _BV(TWEA);  
	len > 0;
	len--)
	{
		 
		if (len == 1)
		{
			twcr = _BV(TWINT) | _BV(TWEN); /* send NAK this time */
			
			}
		TWCR = twcr;      /* clear int to start transmission */
		while ((TWCR & _BV(TWINT)) == 0) ; /* wait for transmission */
		switch ((twst = TW_STATUS))
		{
		case TW_MR_DATA_NACK:
			len = 0;      /* force end of loop */
		 	
		case TW_MR_DATA_ACK:

			*buf++ = TWDR;
			rv++;	
			break;
			
		default:
		 
			goto error;
		}
	}
quit:
	
	TWCR = _BV(TWINT) | _BV(TWSTO) | _BV(TWEN); /* send stop condition */
	 
	 
 
	return rv;
	
error:
	
	rv = -1;
	goto quit;
	
}




/*
*	adr: eerpom address
*	len: length (not use)
*	a: data
*/
int IICWrite_Byte(uint16_t adr, int len, uint8_t a)
{
	uint8_t sla, n = 0;
	int rv = 0;
	uint16_t endaddr;
	DDRB=0XFF;
	
	if (adr + len < (adr | (PAGE_SIZE - 1)))
		endaddr = adr + len;
	else
		endaddr = (adr | (PAGE_SIZE - 1)) + 1;
	len = endaddr - adr;
	
	/* patch high bits of EEPROM address into SLA */
	sla = TWI_SLA_24CXX | (((adr >> 8) & 0x07) << 1);
	
	
restart:
	if (n++ >= MAX_ITER)
		return -1;
begin:
	
	TWCR = _BV(TWINT) | _BV(TWSTA) | _BV(TWEN); /*start  */
	while ((TWCR & _BV(TWINT)) == 0);  
	twst=TW_STATUS;
	if(twst!=TW_START)
	{
			
		return -1;
	}
	


	
	TWDR = sla | TW_WRITE;/* send SLA+W */
	TWCR = _BV(TWINT) | _BV(TWEN);  
	while ((TWCR & _BV(TWINT)) == 0) ;  
	twst=TW_STATUS;
	if(twst!=TW_MT_SLA_ACK)
	{
		return -1;
	}


	TWDR = adr;        /* low 8 bits of addr */
	TWCR = _BV(TWINT) | _BV(TWEN); /* start transmission */
	while ((TWCR & _BV(TWINT)) == 0) ; 
	twst=TW_STATUS;
	if(twst!=TW_MT_DATA_ACK)
	{
		
		return -1;
	}

	
	/************************************/

	TWDR= a; /*data*/
	TWCR= _BV(TWINT)|_BV(TWEN); 
	while((TWCR & _BV(TWINT))==0); 
	
	twst=TW_STATUS;
	if(twst!=TW_MT_DATA_ACK)
	{
		return -1;
	}
	
	
quit:
	
	TWCR = _BV(TWINT) | _BV(TWSTO) | _BV(TWEN); /* stop  */
 
	
	return 1;
	
error:
	rv = -1;
	goto quit;
}
 

FILE mystdout = FDEV_SETUP_STREAM(uart_putchar, NULL, _FDEV_SETUP_WRITE);

void
main(void)
{
	
	uint16_t a;
	int rv=0;
	uint8_t b[200];
	uint8_t x;
	unsigned char address;
	address=95;
	ioinit();
	delay (20);
	_delay_ms(27890);
	DDRB=0XFF;
	k=0;
	int i=0;
	/*IICWrite_Byte(0,10,0);*/
	
	//rv=IICWrite_Byte(0x25,1,0x34);

	//;
	 

  

 while(1)
 {
 	
	for(i=0;i<200;i++)
	{
		b[i]=i;
	}

	for(i=0;i<140;i++)
	{
		
		//rv=IICRead_Byte(0X00,40,&b);
		rv=IICWrite_Byte(i,1,b[i]);
			_delay_ms(50);
	}
	//rv=IICWrite_Byte(0x25,1,0x34);

	_delay_ms(200000);
 	rv=IICRead_Byte(0,14,&b);
	_delay_ms(200000);

 	
 }
 /*
 
	while(1)
	{
	
		_delay_ms(1000);
		if(PIND&(1<<3))
		{
			_delay_ms(10);
			//loop_until_bit_is_set(PIND,3); 
			//
			PORTB=0xff;
			

		}
		else
		{
			_delay_ms(10);
			rv=IICRead_Byte(address,10,&b);
			PORTB=0;
			_delay_ms(70000);
			//address++;


		}
		
		
	}
 
*/


}