EEPROM Problem, able to write once and can not write again

ark5230 · Nov 3, 2014

I am using 24C64 EEPROM and able to write data on that only once.
When I attempt two write again, it fails.
Something serious is missing?
Is it to be erased for reuse, if so How??
Data sheets do not provide information on erasing eeprom.
Any suggestions please !!
I am using AVR Studio and AVRGCC.

FvM · Nov 3, 2014

You mean 24C64 serial EEPROM? It doesn't need data erasure.

May be an I2C protocol problem. Or performing a new write before the previous write has been executed, without ACK polling.

ark5230 · Nov 3, 2014

Thak you very much.
Now I will feagure out problem with the code.

PLAAHemantha · Nov 3, 2014

I'm also have a problem about EEPROM.able to write once and can not write again.
i used this MikroC code and various PIC(16F6XX,16F8XX).

EEPROM_Write(0x02,0xAA); this line work.
EEPROM_Write(0x50,0x55); this line does not work. program is stuck.

pls can anyone help me?

FvM · Nov 3, 2014

According to the manual, mikroC EEPROM library is handling successive write operations, apparently it's using ACK polling but I don't have the compiler and can't check the generated code.

"program is stuck" should never happen, may be a side effect of a different problem.

tantalos · Nov 3, 2014

The 24C64 doesn't need erase before write, it's done internally, but during the write process it will not ACK next transfers on IIC bus. The AVR needs to wait the time specified in the datasheet before trying next IIC transfer.
And reprorgarmming a cell that was written before takes longer than programming a cell that contains 0xFF (because of the additional time that the internal erase needs).

FvM · Nov 3, 2014

The AVR needs to wait the time specified in the datasheet before trying next IIC transfer.

Or implement ACK polling, which is the faster method.

PLAAHemantha · Nov 4, 2014

this is my full codes.
===============================

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unsigned short i, DD0, DD1, DD2, DD3, DD4;
    char temp=0;
 
    unsigned short mask(unsigned short num) {
    switch (num) {
    case 0 : return 0x3F;
    case 1 : return 0x06;
    case 2 : return 0x5B;
    case 3 : return 0x4F;
    case 4 : return 0x66;
    case 5 : return 0x6D;
    case 6 : return 0x7D;
    case 7 : return 0x07;
    case 8 : return 0x7F;
    case 9 : return 0x6F;
    } //case end
    }
 
    unsigned int counter = 0;
    char second = 0;
    char hour = 12;
    char minute = 0;
void interrupt(){
 
         if(PIR1.TMR1IF){
            counter++;
            TMR1H = 0xD8;
            TMR1L = 0xF0;
            if(counter >= 25) {
                counter = 0;
                second++;
                EEPROM_Write(8,second);
                EEPROM_Write(4,minute);
                EEPROM_Write(2,hour);
                
                if (second >= 61){
                   second = 0;
                   minute++;
                  if (minute >= 60){
                     minute = 0;
                     hour++;
                    if (hour >= 13){
                       hour = 1;
                       second += 22;
                    }
                  }
                }
            }
            PIR1.TMR1IF = 0;
 
            if (temp > 0) temp--;
 
          }
    }
 
    void main() {
      CMCON |= 7;
      TRISB = 0b00000000;
      TRISA = 0b00110000;
      PORTB = 0x00;
      PORTA = 0x00;
 
      hour = EEPROM_Read(2);
      minute = EEPROM_Read(4);
 
      TMR1H = 0xD8;
      TMR1L = 0xF0;
 
       T1CON.T1CKPS1 = 1;
       T1CON.T1CKPS0 = 0;
       PIE1.TMR1IE = 1;
 
       INTCON.PEIE = 1;
       INTCON.GIE = 1;
 
       T1CON.TMR1ON = 1;
 
 
      do
      {
         if (PORTA.F4 == 1 && temp == 0)
         {
            PORTB.F7=0;
            if (PORTA.F4==0)
            {
             hour++;
             if (hour >= 13) hour = 1;
            }
            else
            {
             minute++;
             if (minute >= 60) minute = 0;
            }
 
            temp = 12;//doesn't get another button click until a half of second
         }
 
          DD0 = minute%10;
          DD0 = mask(DD0);
 
          DD1 = (minute/10);
          DD1 = mask(DD1);
 
          DD2 = hour%10;
          DD2 = mask(DD2);
 
          DD3 = (hour/10);
          DD3 = mask(DD3);
 
          if (counter > 13) DD4 = 1;
          else DD4 = 0;//blick the LED onece a second
 
          for (i = 0; i<=20; i++) {
              PORTB = DD0;
              PORTA = 1;
              delay_ms(3);
 
              PORTB = DD1;
              PORTA = 2;
              delay_ms(3);
 
              PORTB = DD2;
              PORTA = 4;
              delay_ms(3);
 
              if(DD3 != 63) {
                PORTB = DD3;
                PORTA = 8;
                delay_ms(3);
               }
                
              PORTB = 0x00;
              PORTA = 4;
              PORTB.F7 = DD4; // turn on/off blicking LED
              delay_ms(3);
 
          }
 
       } while(1);          // endless loop
    }

program is stuck at 'EEPROM_Write(4,minute);' line.
It is seen as program is running, but do not flow.
pls help me.

FvM · Nov 4, 2014

Never use EEPROM write routines in interrupt!

tantalos · Nov 4, 2014

PLAAHemantha said:

this is my full codes.
===============================

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unsigned short i, DD0, DD1, DD2, DD3, DD4;
    char temp=0;
 
    unsigned short mask(unsigned short num) {
    switch (num) {
    case 0 : return 0x3F;
    case 1 : return 0x06;
    case 2 : return 0x5B;
    case 3 : return 0x4F;
    case 4 : return 0x66;
    case 5 : return 0x6D;
    case 6 : return 0x7D;
    case 7 : return 0x07;
    case 8 : return 0x7F;
    case 9 : return 0x6F;
    } //case end
    }
 
    unsigned int counter = 0;
    char second = 0;
    char hour = 12;
    char minute = 0;
void interrupt(){
 
         if(PIR1.TMR1IF){
            counter++;
            TMR1H = 0xD8;
            TMR1L = 0xF0;
            if(counter >= 25) {
                counter = 0;
                second++;
                EEPROM_Write(8,second);
                EEPROM_Write(4,minute);
                EEPROM_Write(2,hour);
                
                if (second >= 61){
                   second = 0;
                   minute++;
                  if (minute >= 60){
                     minute = 0;
                     hour++;
                    if (hour >= 13){
                       hour = 1;
                       second += 22;
                    }
                  }
                }
            }
            PIR1.TMR1IF = 0;
 
            if (temp > 0) temp--;
 
          }
    }
 
    void main() {
      CMCON |= 7;
      TRISB = 0b00000000;
      TRISA = 0b00110000;
      PORTB = 0x00;
      PORTA = 0x00;
 
      hour = EEPROM_Read(2);
      minute = EEPROM_Read(4);
 
      TMR1H = 0xD8;
      TMR1L = 0xF0;
 
       T1CON.T1CKPS1 = 1;
       T1CON.T1CKPS0 = 0;
       PIE1.TMR1IE = 1;
 
       INTCON.PEIE = 1;
       INTCON.GIE = 1;
 
       T1CON.TMR1ON = 1;
 
 
      do
      {
         if (PORTA.F4 == 1 && temp == 0)
         {
            PORTB.F7=0;
            if (PORTA.F4==0)
            {
             hour++;
             if (hour >= 13) hour = 1;
            }
            else
            {
             minute++;
             if (minute >= 60) minute = 0;
            }
 
            temp = 12;//doesn't get another button click until a half of second
         }
 
          DD0 = minute%10;
          DD0 = mask(DD0);
 
          DD1 = (minute/10);
          DD1 = mask(DD1);
 
          DD2 = hour%10;
          DD2 = mask(DD2);
 
          DD3 = (hour/10);
          DD3 = mask(DD3);
 
          if (counter > 13) DD4 = 1;
          else DD4 = 0;//blick the LED onece a second
 
          for (i = 0; i<=20; i++) {
              PORTB = DD0;
              PORTA = 1;
              delay_ms(3);
 
              PORTB = DD1;
              PORTA = 2;
              delay_ms(3);
 
              PORTB = DD2;
              PORTA = 4;
              delay_ms(3);
 
              if(DD3 != 63) {
                PORTB = DD3;
                PORTA = 8;
                delay_ms(3);
               }
                
              PORTB = 0x00;
              PORTA = 4;
              PORTB.F7 = DD4; // turn on/off blicking LED
              delay_ms(3);
 
          }
 
       } while(1);          // endless loop
    }

program is stuck at 'EEPROM_Write(4,minute);' line.
It is seen as program is running, but do not flow.
pls help me.

Can you show us the schematics and the EEPROM_Write routine.

FvM · Nov 4, 2014

Can you show us the schematics and the EEPROM_Write routine.

It's a built-in mikroC library function.

Easyrider83 · Nov 4, 2014

Code:

u8 I2C_24C_EEPROM_Write_Page (u8 I2c_Address, u16 Mem_Address, char * pBuffer)
{
  u8 err=0;
  err=I2c_Start(EEPROM_I2Cx);
  if (err) return err;
  err=I2c_WriteAddress(EEPROM_I2Cx, I2c_Address);
  if (err) return err;
  I2c_WriteByte(EEPROM_I2Cx, (0xFF00&Mem_Address)>>8);
  I2c_WriteByte(EEPROM_I2Cx, 0xFF&Mem_Address);
  while (* pBuffer) I2c_WriteByte(EEPROM_I2Cx, * pBuffer++);
  I2c_Stop(EEPROM_I2Cx);
	delay_ms(10);
  return I2c_Success;
}

u8 I2C_24C_EEPROM_Write_Page_ByLen (u8 I2c_Address, u16 Mem_Address, char * pBuffer, u16 Len)
{
  u8 err;
	u8 PagesWritten = 0;
	u8 BytesToWrite;
	while (Len)
	{	
		if (Len<MaxPageSizeBytes) 
		{
			BytesToWrite = Len;
			Len = 0;
		}
		else 
		{
			BytesToWrite = MaxPageSizeBytes;
			PagesWritten++;
			Len-= MaxPageSizeBytes;
		}
		
		err=I2c_Start(EEPROM_I2Cx);
		if (err) return err;
		err=I2c_WriteAddress(EEPROM_I2Cx, I2c_Address);
		if (err) return err;
		I2c_WriteByte(EEPROM_I2Cx, (0xFF00&Mem_Address)>>8);
		I2c_WriteByte(EEPROM_I2Cx, 0x00FF&Mem_Address);
		while (BytesToWrite--) I2c_WriteByte(EEPROM_I2Cx, * pBuffer++);
		I2c_Stop(EEPROM_I2Cx);
		delay_ms(I2c_EEPROM_WriteTime_ms);
		
		Mem_Address+= MaxPageSizeBytes;
	}
  return I2c_Success;
}

u8 I2C_24C_EEPROM_Read_Byte (u8 I2c_Address, u16 Mem_Address, char * pBuffer)
{
  u8 err;
  err=I2c_Start(EEPROM_I2Cx);
  if (err) return err;
  err=I2c_WriteAddress(EEPROM_I2Cx, I2c_Address);
  if (err) return err;
  I2c_WriteByte(EEPROM_I2Cx, (0xFF00&Mem_Address)>>8);
  I2c_WriteByte(EEPROM_I2Cx, 0xFF&Mem_Address);
  I2c_ReStart(EEPROM_I2Cx);
  I2c_NACK(EEPROM_I2Cx);
  I2c_WriteAddress(EEPROM_I2Cx, I2c_Address|1);
  * pBuffer = I2c_ReadByte(EEPROM_I2Cx);
  I2c_Stop(EEPROM_I2Cx);
  I2c_ACK(EEPROM_I2Cx);
  return I2c_Success;
}

u8 I2C_24C_EEPROM_Read_Page (u8 I2c_Address, u16 Mem_Address, char * pBuffer, u8 pBufferSize)
{
  u8 err=0;
	I2c_ACK(EEPROM_I2Cx);
  err=I2c_Start(EEPROM_I2Cx);
  if (err) return err;
  err=I2c_WriteAddress(EEPROM_I2Cx, I2c_Address);
  if (err) return err;
  I2c_WriteByte(EEPROM_I2Cx, (0xFF00&Mem_Address)>>8);
  I2c_WriteByte(EEPROM_I2Cx, 0xFF&Mem_Address);
  I2c_ReStart(EEPROM_I2Cx);
  I2c_WriteAddress(EEPROM_I2Cx, I2c_Address|1);
  I2c_ACK(EEPROM_I2Cx);
  while (pBufferSize) 
  {
    * pBuffer++ = I2c_ReadByte(EEPROM_I2Cx);
    pBufferSize--;
    if (!pBufferSize) I2c_NACK(EEPROM_I2Cx);
  }
  I2c_Stop(EEPROM_I2Cx);
  
  return I2c_Success;  
}

ark5230 · Nov 9, 2014

FvM, Easyrider83 and all.
I was trying at all possible issues but The 24C64 was defective.
I had 3 of them, when I changed this every thing went fine.
I am writing about 8 K byte of data.
In every write process at least 12 bytes are written incorrect.
This is a new situation, every time the byte locations are different.
I am trying to figure out the problem but hope this will not be too difficult to fix.
Thanks to every body for the help.
Any suggestions regarding new situation are welcome.

FvM · Nov 9, 2014

Smells like a coding problem...

milan.rajik · Nov 9, 2014

@PLAAHemantha

If you use mikroC EEPROM routimes then you should use a delay of 20 ms minimum after each EEPROM read or write operation.

ark5230 · Nov 9, 2014

I suspect similar thing related to code, directly or through borrowed roitines from libraries and include filed.
delay is also to be taken seriously as pointed out.

EEPROM Problem, able to write once and can not write again

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