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01/28/09 14:58
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#161787 - Accessing internal EEPROM of 89S8253
Hello sir,
For my project, I want to use internal EEPROM of IC AT89S8253. So I have written a dummy code to access internal EEPROM of IC 89S8253. But I am facing the following probem:

I am not getting the desired output after retrieving data from EEPROM.I am storing 5 in EEPROM and reading the same from it. But 4 is displayed on LCD. THe bits EEMEN (Access enable) and EEMWE (Write enable) are set while writing into the EEPROM. Even if change value from 5 to 6, 7 or any other value, I am getting 4 displayed on LCD.

The code has been implemented as follows:



WRITE:  MOV DPTR,#96H        ;ADDRESS OF EECON
        MOV A,#1BH
        MOVX @DPTR,A         ;SET WRITE AND ACCESS ENABLE
       
CHECK:  MOVX A,@DPTR
        CJNE A,#01BH,COMP    ;CHECK IF EEPROM IS BUSY

        MOV DPTR,#10H        ;LOCATION IN EEPROM
        MOV A,#05
        MOVX @DPTR,A         ;STORE 5 AT  10H LOCATION
        SJMP CHECK

COMP:   MOV A,#0BH           ;RESET WRITE ENABLE
        MOV DPTR,#96H
        MOVX @DPTR,A 

READ:   MOV DPTR,#10H
        MOVX A,@DPTR         ;READ DATA FROM 10H          
        ACALL DISPLAY
END:    SJMP END



Please, could someone help me out by pointing out where I could be going wrong and as to why I am not able to get the same data on LCD. I have checked on Pseudomax Simulator that the code works fine. My LCD routines are working fine as I have used them for other codes of project.










List of 5 messages in thread
TopicAuthorDate
Accessing internal EEPROM of 89S8253            01/01/70 00:00      
   EECON is SFR            01/01/70 00:00      
      Thanx for the help.            01/01/70 00:00      
         Always a good starting point...            01/01/70 00:00      
   89s8253            01/01/70 00:00      

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