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How to program EEPROM correctly? SAved but recall FAILED


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nicholastyc

Fri May 16 2008, 01:03AM

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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...

[ Edited Fri May 16 2008, 10:58PM ]

Ajay

Fri May 16 2008, 11:06PM

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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.

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nicholastyc

nicholastyc

Sun May 18 2008, 06:35PM

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Joined: Wed May 07 2008, 07:13PM

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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!!

Ajay

Mon May 19 2008, 12:41AM

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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.

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nicholastyc

Mon May 19 2008, 01:38AM

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Joined: Wed May 07 2008, 07:13PM

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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.