Differences

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--- code:i2c_eeprom [2008/11/19 13:51] – laurenceb
+++ code:i2c_eeprom [2009/03/20 04:50] (current) – laurenceb
@@ Line 16: / Line 16: @@
 void i2cstart()
 {
+	u16 timeout=1;
 	TWCR = (1<<TWINT)|(1<<TWSTA)|(1<<TWEN);	//send start
-	while (!(TWCR & (1<<TWINT)));			//wait for a start to be transmitted
+	while (!(TWCR & (1<<TWINT)) && timeout)
+		timeout++;							//wait for a start to be transmitted
+	if(!timeout)
+		I2Cerr|=16;							//timeout out waiting for start error
 	TWCR = (1<<TWEN );						//clear the start condition
 	if (((TWSR & 0xF8) != TW_START)&&((TWSR & 0xF8) != TW_REP_START))
@@ Line 25: / Line 29: @@
 void i2cstop()
 {
+	u16 timeout=1;
 	TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWSTO);
-	while (!(TWCR & (1<<TWSTO)));			//wait for stop to be sent
+	while (!(TWCR & (1<<TWSTO)) && timeout)	//wait for stop to be sent
+		timeout++;
+	if(!timeout)
+		I2Cerr|=64;							//timeout waiting for stop error
 }
 void i2cwrite(u08 c)
 {
+	u16 timeout=1;
 	TWDR = c;								//load the data
 	TWCR = (1<<TWINT)|(1<<TWEN);
-	while (!(TWCR & (1<<TWINT)));			//wait for it to be sent
+	while (!(TWCR & (1<<TWINT)) && timeout)	//wait for it to be sent
+		timeout++;
+	if(!timeout)
+		I2Cerr|=32;							//timeout out waiting for write complete error
 	if ( ((TWSR&0xF8)!=TW_MT_SLA_ACK)&&((TWSR&0xF8)!=TW_MR_SLA_ACK)&&((TWSR&0xF8)!=TW_MT_DATA_ACK) )
 		I2Cerr|=2;							//error
 }
-u08 i2cread(u08 AK)
+u08 i2cread(u08 ak)
 {
 	u16 timeout=1;
-	TWCR=AK;
+	TWCR=ak;
-	while (!(TWCR & (1<<TWINT)) & timeout)
+	while ((!(TWCR & (1<<TWINT))) && timeout)
 		timeout++;							//wait for it to be recieved
 	if(!timeout)
-		I2Cerr|=8;							//timeout out waiting for data error
+		I2Cerr|=8;							//timeout out waiting for data response error
 	if(((TWSR & 0xF8) !=TW_MR_DATA_ACK) && ((TWSR & 0xF8) !=TW_MR_DATA_NACK))
 		I2Cerr|=4;
@@ Line 57: / Line 69: @@
 {
 	i2cstart();
-	i2cwrite(SLA_W|(((*address)>>15)&0x08));	//the block
+	i2cwrite(SLA_W|(((*address)>>15)&0x02));	//the block
 	i2cwrite((u08)((*address)>>8));				//address write MSB
 	i2cwrite((u08)(*address));					//address write LSB
@@ Line 67: / Line 79: @@
 	for(n=0;n<datasize;n++,(*address)++)
 	{
-		if(!(((u08)*address)&0xEF))				//check the address for overflow for the 7 LSB
+		if(!((u08)*address))					//check the address for overflow for the 8 LSB (Atmel)
 		{
 			i2cstop();							//triggers a page write
-			_delay_loop_2( (u16) ( (float)F_CPU*0.003/4.0 ) );//delay 3 ms for page write
+			_delay_loop_2( (u16) ( (float)F_CPU*0.006/4.0 ) );//delay 6 ms for page write
 			set_address(address);				//set the new address
 		}
@@ Line 82: / Line 94: @@
 	datasize--;
 	i2cstart();
-	i2cwrite(SLA_R|(((*address)>>15)&0x08));	//set read to the correct block
+	i2cwrite(SLA_R|((u08)((*address)>>15)&0x02));	//set read to the correct block
-	for(n=0;n<datasize;n++)
+	for(n=0;n<datasize;n++)						//the eeproms address pointer should have been setup already
 	{
 		destination[n]=i2cread(_AK_);
 		(*address)++;							//increment our pointer
-		if(!(u16)*address)						//we reached the end of the block
+		/*if(!(u16)(*address))					//we reached the end of the block
 		{
 			i2cstop();
 			set_address(address);
-		}
+		}This isn't needed on the Atmel chips*/
 	}
-	destination[datasize+1]=i2cread(_NAK_);		//send NAK for the last byte recieved
+	destination[datasize]=i2cread(_NAK_);		//send NAK for the last byte recieved
+	i2cstop();
+	(*address)++;
 }
 u32 findtop()									//Find the address of record number where we enter painted eeprom
 {
-	u32 top=0;									//half way through rounded to nearest 12
+	u32 top=12*((u32)1<<13);					//half way through rounded down to 12
-	u08 n;
+	u08 n,endcond=TRUE;
-	for(n=17;n;)								//start by probing half way through
+	u16 place=1<<13;
+	for(n=14;endcond;)							//start by probing half way through - place is in records
 	{
-		n--;
-		top+=1<<n;								//trial setting of bit
-		top = 12*( (u32) (top/12) );			//round down to nearest 12
 		set_address(&top);						//the probe address
+		if(n)
+			n--;								//need to decr here to get 1 byte resolution
+		else
+			endcond=FALSE;						//terminate the loop after completion									//need to decr here to get 1 byte resolution
+		i2cstart();								//read the slave
+		i2cwrite(SLA_R);
 		if(i2cread(_NAK_)==MAGIC_NUMBER)		//see if its painted
-			top-=1<<n;							//clear the nth bit
+			place&=~(1<<n);						//clear the nth bit in the place holder
+		if(n)
+			place|=(1<<(n-1));					//set the next bit
+		i2cstop();
+		if(place>10922)
+			place=10922;
+		top = 12*( (u32)place );				//place is in units of 12
 	}
-	top =12*( (u32) (top/12) );					//make sure our answer is rounded correctly
+	set_address(&top);
+	i2cstart();
+	i2cwrite(SLA_R);
+	if(i2cread(_NAK_)!=MAGIC_NUMBER)			//check the location to make sure its blank
+		place++;
+	top = 12*( (u32)place );
 	return top;
 }
@@ Line 117: / Line 147: @@
 	u08 magic=MAGIC_NUMBER;						//magic is our painting value
 	u32 n=0;
-	for(n=0;n<131072;n+=11)						//need to skip 11 bytes between each write location
+	for(;n<131072;n++/*n+=12*/)					//this writes every (12th) byte
 	{
-		set_address(&n);						//set the eeproms internal address register
+		/*
-		write_data(&magic,1,&n);				//write the data
+		set_address(&n);
+		i2cwrite(magic);						//write the data
+		if((u08)n>243)							//our next n will be across a page boundary
+		{
+			i2cstop();
+			_delay_loop_2( (u16) ( (float)F_CPU*0.006/4.0 ) );//delay 6 ms for page write
+		}*/
+		if(!((u08)n))							//this code is for writing every byte
+		{
+			i2cstop();
+			_delay_loop_2( (u16) ( (float)F_CPU*0.006/4.0 ) );//delay 6 ms for page write
+			set_address(&n);
+		}
+		i2cwrite(magic);
+		wdt_reset();
 	}
+	i2cstop();
 }
 #endif