[SOLVED] Unable read from EEPROM using PIC30F5011

[Raady Here]

HI ,

I am trying to read and write to EEPROM 24LC256 using I2C , but when I am trying with a string , the LCD doesn't display any thing.
(I tried other program displaying on LCD, and no problem with LCD functionality.)

Please let me know if I am missing some logic,

I have used library functions of PIC30F5011 in MPLAB 8.8

	#define value4		0x0004
	#define value5		0x0005
main(){

	unsigned char testarr1[] = "String 1";
	unsigned char testarr2[] = "String 2";
	unsigned char disarr1[9];          // array 1
	unsigned char disarr2[9];          // array 2
        Write_String_EEPROMx(8,testarr1,value4); // writing to EEPROM
	Write_String_EEPROMx(8,testarr2,value5);

        Read_String_EEPROMx(8,disarr1,value4);  // Read from EEPROM
	Read_String_EEPROMx(8,disarr2,value5);

        XLCDCommand(0x94);
	XLCDPutRamString((const char)disarr1); // display on LCD.
	XLCDCommand(0xD4);
	XLCDPutRamString((const char)disarr2);
}


void Write_String_EEPROMx(unsigned char length, unsigned char *arr,unsigned int Address)
{
	EEPROM_WP_Disable;
	WaitI2C(10000);							// Inital delay
	add.value = Address;
	IdleI2C();
	StartI2C();
	IdleI2C();
	MasterWriteI2C(EEPROM_WRITE_ID);       		// Write Control byte
	IdleI2C();
        while(I2CSTATbits.ACKSTAT);
	MasterWriteI2C(add.msb);					// write MSB Address
   	IdleI2C();
        while(I2CSTATbits.ACKSTAT);
	MasterWriteI2C(add.lsb);					// write LSB Address
	IdleI2C();
        while(I2CSTATbits.ACKSTAT);
        while(length--)
	{
		MasterWriteI2C(*arr++);       		// Write data byte
		IdleI2C();
	        while(I2CSTATbits.ACKSTAT);
	}			    					// write string
        while(I2CSTATbits.ACKSTAT);
	StopI2C();
	IdleI2C();
	EEPROM_WP_Enable;
}


unsigned char Read_String_EEPROMx(unsigned int length, unsigned char *arr, unsigned int Address)
{

	WaitI2C(10000);											
	add.value = Address;
	IdleI2C();
	StartI2C();
	IdleI2C();
	MasterWriteI2C(EEPROM_WRITE_ID);       		// Write Control byte
	IdleI2C();
	MasterWriteI2C(add.msb);					// write MSB Address
   	IdleI2C();
	MasterWriteI2C(add.lsb);					// write LSB Address
	IdleI2C();
	RestartI2C();
   	IdleI2C();
	MasterWriteI2C(EEPROM_READ_ID);       		// Read Control byte
	IdleI2C();
	
	while( length > 1 )
   	{
	    *arr++ = MasterReadI2C();
		IdleI2C();
    	Nop();
		AckI2C();
		IdleI2C();
		length--;
		*arr = '\0';
	}	
       *arr++ = MasterReadI2C();
       *arr = '\0';
    
	IdleI2C();
	NotAckI2C();
	IdleI2C();
	StopI2C();
	IdleI2C();
	return 1;
}

 

[jumanji]

First question: where are EEPROM_WRITE_ID and EEPROM_READ_ID defined?
Second question: have you used a scope or logic analyzer to determine if the write and/or read are working? ie., is the eeprom sending acks back?

If you do not already have a scope or logic analyzer and you plan on writing code that utilizes communication such as SPI, I2C or RS232, I HIGHLY recommend the Salae USB logic analyzer. (https://www.saleae.com/logic/) It is only $150,is super simple to use and shows you both waveforms and data coming across. It has saved me countless hours of frustration. I do NOT work for Salae - I just use one frequently and when I am working on any code that involves communication I hook it up before I even start testing because I know I am going to need it.

 

[Duresh]

Hello,
I think this is a problem in using pointer.
In the function "Write_String_EEPROMx()" you request a pointer as 2nd arg. But you haven't pass a a pointer.
Change,

Write_String_EEPROMx(8,testarr1,value4)

to this

Write_String_EEPROMx(8,&testarr1[0],value4)

Use this method in Reading function also.