Differences

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--- code:i2c_eeprom [2008/11/06 00:24] – laurenceb
+++ code:i2c_eeprom [2009/03/20 04:50] (current) – laurenceb
@@ Line 11: / Line 11: @@
 void init_i2c()
 {
-	TWBR=(u08)((float)F_CPU/(2*SCL)-8.0);	//sets the correct clock rate defined as SCL
+	TWBR=(u08)(((float)F_CPU/(2.0*(float)SCL))-8.0);//sets the correct clock rate defined as SCL
-}						//we dont need to enable the hardware - its done in write
+}											//we dont need to enable the hardware - its done in write
 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))
-		I2Cerr|=1;			//error
+		I2Cerr|=1;							//error
 }
-#define i2cstop TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWSTO)
+void i2cstop()
+{
+	u16 timeout=1;
+	TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWSTO);
+	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)
 {
-	TWDR = c;				//load the data
+	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
-	if ( ((TWSR & 0xF8) !=TW_MT_SLA_ACK) & ((TWSR & 0xF8) !=TW_MR_SLA_ACK) )
+		timeout++;
-		I2Cerr|=2;			//error
+	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
+		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)
+	if(((TWSR & 0xF8) !=TW_MR_DATA_ACK) && ((TWSR & 0xF8) !=TW_MR_DATA_NACK))
 		I2Cerr|=4;
 	return TWDR;
@@ Line 49: / Line 66: @@
 //Designed for 12 byte records atm
-void set_address(u32 * address)				//Sets an address from a paointer - cannot switch between physical devices
+void set_address(u32 * address)					//Sets an address from a pointer - can select the correct physical device but reqires idle bus
 {
 	i2cstart();
-	i2cwrite(SLA_W|(((*address)>>13)&0x08));	//the block
+	i2cwrite(SLA_W|(((*address)>>15)&0x02));	//the block
-	i2cwrite((u08)((*address)>>8));			//address write MSB
+	i2cwrite((u08)((*address)>>8));				//address write MSB
-	i2cwrite((u08)(*address));			//address write LSB
+	i2cwrite((u08)(*address));					//address write LSB
 }
 void write_data(u08 * c, u08 datasize, u32 * address)//The address will be incremented as the data is written
 {
-	u08 n;						//up to 256 bytes can be written at once
+	u08 n;										//up to 256 bytes can be written at once
 	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
+			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
+			set_address(address);				//set the new address
 		}
-		i2cwrite(c[n]);				//write the data
+		i2cwrite(c[n]);							//write the data
 	}
 }
@@ Line 77: / Line 94: @@
 	datasize--;
 	i2cstart();
-	i2cwrite(SLA_R|(((*address)>>13)&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
+		(*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;
+			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 findtop()									//Find the address of record number where we enter painted eeprom
 {
-	u32 top=65532;					//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;
-	u08 probe;
+	u16 place=1<<13;
-	for(n=17;n;n--)					//start by probing half way through
+	for(n=14;endcond;)							//start by probing half way through - place is in records
 	{
-		set_address(&top);			//the probe address
+		set_address(&top);						//the probe address
-		probe=i2cread(_AK_);			//read some data from there
+		if(n)
-		if(probe!=MAGIC_NUMBER)			//see if its unpainted
+			n--;								//need to decr here to get 1 byte resolution
-		{
+		else
-			top|=1<<(n-1);
+			endcond=FALSE;						//terminate the loop after completion									//need to decr here to get 1 byte resolution
-			top = 12* ( (u32) ( (top | (1<<(n-1))) / 12) );//round down to nearest 12
+		i2cstart();								//read the slave
-		}
+		i2cwrite(SLA_R);
+		if(i2cread(_NAK_)==MAGIC_NUMBER)		//see if its painted
+			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
 	}
+	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;
 }
-void painteeprom()					//Paints every 12th location with the magic number
+void painteeprom()								//Paints every 12th location with the magic number
 {
-	u08 magic=MAGIC_NUMBER;				//magic is our painting value
+	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
@@ Line 124: / Line 172: @@
 ===== I2Cmem.h =====
-<code c>
+<code c>#include <util/twi.h>						//I2C registers
-#include <util/twi.h>						//I2C registers
 #include <util/delay_basic.h>					//wait delay loop for page write
 #include "avrlibtypes.h"
@@ Line 139: / Line 186: @@
 void init_i2c();
 void i2cstart();
+void i2cstop();
 void i2cwrite(u08 c);
 u08 i2cread(u08 AK);