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How to program EEPROM correctly? SAved but recall FAILED

Fri, 16 May 2008 01:03:05 -0700

Hi,
Ajay, this is my last problem, i already solved the INput problems,
for pic12f629, to enable the GPIO 4,5 , you must configure the Internal Clock and other config, as below.
__CONFIG _CP_OFF & _MCLRE_OFF & _WDT_OFF & _INTRC_OSC_NOCLKOUT & _BODEN_OFF & _CPD_OFF &_PWRTE_OFF

This does not been told in the datasheet.

By the way, my new problem is i saved my data (0x01) into eeprom address 0x01, when i recall the data it does not recall the same data but something different from it and sometimes i can save the data and recall correctly but sometimes not.
What is the problem? is the setting or code problems? i already DOUBLExDouble check it in the DATASHEET for few hours and look for solutions on internet, i still cant recall correctly, PLEASe HELP.I write the data correctly...everytime, when i check in the EEDATA register b4 i reset the MPLAB SIM and rerun again.
Code Below, PIC12F629 ,
WRITE code from me,

CODE:

ORIGINAL_PWM EQU 0x21
TEMP EQU 0x22
WRITE:  BSF     STATUS,5; switch to bank 1
        MOVLW   0x01; go to addr 0x01
        MOVWF   EEADR;
        MOVF    ORIGINAL_PWM,w  ; (ORIGINAL_PWM = 0x01)
        MOVWF   EEDATA; write 0x01 to EEDATA
        BSF     EECON1,WREN; < follow the datasheet write process
        BCF     INTCON,GIE      ;<
        MOVLW   H'0055' ;<
        MOVWF   EECON2  ;<
        MOVLW   H'00AA'         ;<
        MOVWF   EECON2  ;<
        BSF     EECON1,WR       ;<
        BSF     INTCON,GIE      ;<
        BCF     STATUS,5; switch to bank 0
        RETURN

READ:   BSF     STATUS,5; switch to bank 1
        MOVLW   0x01; goto addr 0x01 in eeprom
        MOVWF   EEADR;
        BSF     EECON1,RD       ; read previously saved data 0x01
        MOVF    EEDATA,w        ; move 0x01 to w
        MOVWF   TEMP; (TEMP register ) move 0x01 to TEMP
        BCF     STATUS,5; switch bank 0
        RETURN

Thanks for your help....mmy last problem...

Re: How to program EEPROM correctly? SAved but recall FAILED

Fri, 16 May 2008 23:06:08 -0700

after you set WR bit in EECON1 register you need to poll that bit till the writing is finished. Do not confuse writing in flash with writing to EEPROM.

When you write in flash, cpu stalls itself till writing is finished so no need to poll in that case, whereas in case of EEPROM, you need to poll the WR bit in EECON1 register. Try again..

use test bit instruction for checking WR bit. Please ask if you still feel any problem working on it.

Re: How to program EEPROM correctly? SAved but recall FAILED

Mon, 19 May 2008 01:38:25 -0700

thank you very much Ajay...

i made a statement like this,

btfsc EECON1, WR;
goto $-1 ;

it looks fine... but the main problem still is the MPLAB SIM, when i simulate it in ANIMATION mode, its just keep looping...and u know wat, but i go to the RUN mode, everything just works fine and the EEPROM is saving the data n recall. Hope it will work fine in the PIC after i program it tomorrow, lets c how tomorrow. Thanks for your help.

Re: How to program EEPROM correctly? SAved but recall FAILED

Sun, 18 May 2008 18:35:02 -0700

hi Ajay, wat is poll the WR bit means?
i m a newbie here...

please explain in asm or meaning of poll the WR bit..

thanks!!

Re: How to program EEPROM correctly? SAved but recall FAILED

Mon, 19 May 2008 00:41:13 -0700

polling means waiting...
it can be done something like this...

CODE:

wait:
        btfsc EECON1,WR //skip the next statement if the bit is cleared
        bra wait  //jump back and check again
        return  //return when bit is cleared.
 

Re: How to program EEPROM correctly? SAved but recall FAILED

Mon, 19 May 2008 20:22:01 -0700

try using label instead of $-1

I hope it will work..