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???
07/21/11 06:14
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 		 #182940 - use DATA RAM as EEPROM
Responding to: ???'s previous message
Maunik Choksi said:
use DATA RAM as EEPROM.

What, exactly, do you mean by that?

Do you mean, you want (part of) the DATA RAM to be non-volatile?

Is it possible & if yes how ?


To make the DATA RAM non-volatile would require two things:

1. Some kind of backup power suppyly;

2. Ensure that your code does not overwrite the DATA RAM during startup.

You will probably also want to put the processor into a low-power mode during the "data-retention" state, and have some integrtiy check on the contents...

can you give some source code of it


Would need more details - including what tools you use...

IIRC, Philips application note AN10210 illustrated putting an 8051 into low-power mode and retaining data in RAM.
The PDF is here: http://www.nxp.com/documents...N10210.pdf

I think you had to specifically request the source code from Philips - now NXP...

List of 37 messages in thread
TopicAuthorDate
about P89LV51RD2FN            01/01/70 00:00      
   use DATA RAM as EEPROM            01/01/70 00:00      
   Do you want read-only?            01/01/70 00:00      
      external memory chips            01/01/70 00:00      
   Data Ram ? Not!!            01/01/70 00:00      
      Requirements            01/01/70 00:00      
         shifting of EEPROM            01/01/70 00:00      
            You want to remove external EEPROM - why?            01/01/70 00:00      
            The 93C46 is only 128 bytes            01/01/70 00:00      
            So why choose the P89LV51RD2FN, then??            01/01/70 00:00      
               IAP            01/01/70 00:00      
                  Harvard Architecture            01/01/70 00:00      
                     IAP vs External Serial EEPROM            01/01/70 00:00      
                        Serial EEPROM            01/01/70 00:00      
                           MOVX or MOVC is fairly similar            01/01/70 00:00      
                              choose an MCU with proper eeprom            01/01/70 00:00      
   the P89LV51RD2 can support this            01/01/70 00:00      
      already mentioned            01/01/70 00:00      
      erase & write            01/01/70 00:00      
         Why make life difficult for yourself?            01/01/70 00:00      
            another chip            01/01/70 00:00      
               Choose carefully!            01/01/70 00:00      
               P89LV51RD2FN IAP write endurance            01/01/70 00:00      
                  elegant solution?            01/01/70 00:00      
                     better one            01/01/70 00:00      
                        Check out this one...            01/01/70 00:00      
                           availability?            01/01/70 00:00      
                              I'll Admit....            01/01/70 00:00      
                                 Atmel parts availability            01/01/70 00:00      
                                    Onchip nonvolatile RAM            01/01/70 00:00      
                                       Link.            01/01/70 00:00      
                                       Happy With Package Options ?            01/01/70 00:00      
                                          about plcc package            01/01/70 00:00      
                                             If you're changing the package anyhow...            01/01/70 00:00      
                                                selection of plcc            01/01/70 00:00      
                                                   Why socket?            01/01/70 00:00      
            an alternative            01/01/70 00:00      

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