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Problems with eeprom R/W

Michael Christensen

Hi
I want to read and write to the internal eeprom in the at89c51ed2. In simulation it seams OK, but in target, the volatile memory is allways read as 0xffh. I use the same routines for same processor in a different project without problems.
My test looks as follows:

IntTemp = 100;
eep_write(0,IntTemp);
i = eep_read(0);
if ( i !=IntTemp )
{
 error(1);
}

Can any of you help me?

My writing routine looks as follows:
void eep_write(byte address, int wdata)
{
bit	tmpEA = EA; //store EA state
 EA = 0;
 EECON = 0x02; // Enable EEPROM
 XWORD[address] = wdata;
 EECON = 0x50; //necessary for simulation to work, why?
 EECON = 0xa0; //same as above
 EECON &= ~0x02;
 EA = tmpEA;
 while(EECON & 1);
}
My reading routine looks as follows:
int eep_read(byte address)
{
bit tmpEA = EA;
int read_data;
 while(EECON & 1);
 EA = 0;
 EECON |= 2; // Map eeprom
 read_data = XWORD[address];
 EECON &= ~2; // Unmap eeprom
 EA = tmpEA;
 return(read_data);
}
Thanks!

Parents
  • 0 in reply to Zona Z

    Well, after all I have the way:

    unsigned char __api_rd_eeprom_byte(unsigned int adr)
    {
    unsigned char val;
    bit ea_save;
    while (EECON&1)
    {WDT_feed; //Watch dog,this "while" many be few mS when you W/R continously
    };//Eeprom_busy()
    ea_save=EA;
    EA=0;
    EECON |= 0x02;//Enable eeprom data;
    val=*(unsigned char xdata*)adr;
    EECON &= ~0x02;//Disable eeprom data;
    EA=ea_save;
    return val;
    }


    void __api_wr_eeprom_byte(unsigned int adr, unsigned char value)
    {
    bit ea_save;
    while(EECON & 0x01)
    {WDT_feed; //Watch dog,this "while" many be few mS when you W/R continously
    };// wait bit busy
    ea_save=EA;
    EA=0;
    EECON |= 0x02;//Enable eeprom data
    *(unsigned char xdata*)adr=value;
    EECON &= ~0x02;//Disable eeprom data
    EA=ea_save;
    }

    the api only support 1B's R/W, so you should do the managment of WORD/DWORD type's Read/Wrote...


    Michael Christensen 's problem is because his routine is for T89C51ED2, not AT89C51ED2, Atmel has a pdf told you the difference between these 2chip... and the routine in this post is for AT89C51ED2... Hope it can help the newer...

Reply
  • 0 in reply to Zona Z

    Well, after all I have the way:

    unsigned char __api_rd_eeprom_byte(unsigned int adr)
    {
    unsigned char val;
    bit ea_save;
    while (EECON&1)
    {WDT_feed; //Watch dog,this "while" many be few mS when you W/R continously
    };//Eeprom_busy()
    ea_save=EA;
    EA=0;
    EECON |= 0x02;//Enable eeprom data;
    val=*(unsigned char xdata*)adr;
    EECON &= ~0x02;//Disable eeprom data;
    EA=ea_save;
    return val;
    }


    void __api_wr_eeprom_byte(unsigned int adr, unsigned char value)
    {
    bit ea_save;
    while(EECON & 0x01)
    {WDT_feed; //Watch dog,this "while" many be few mS when you W/R continously
    };// wait bit busy
    ea_save=EA;
    EA=0;
    EECON |= 0x02;//Enable eeprom data
    *(unsigned char xdata*)adr=value;
    EECON &= ~0x02;//Disable eeprom data
    EA=ea_save;
    }

    the api only support 1B's R/W, so you should do the managment of WORD/DWORD type's Read/Wrote...


    Michael Christensen 's problem is because his routine is for T89C51ED2, not AT89C51ED2, Atmel has a pdf told you the difference between these 2chip... and the routine in this post is for AT89C51ED2... Hope it can help the newer...

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