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???
01/07/10 09:06
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#172226 - Yes
Responding to: ???'s previous message
Andy Neil said:
And that would be more "complicated" (sic?) than the standard parallel external memory interface - which was the original objection to external memory!

Yes, glue logic that maintained a n-level write-back queue would be a beauty of "simplicity" to implement - especially if it also needs to have a look-ahead snoop in case a read is made of an entry still in the pipeline :)

In a very large percentage of the cases where a microcontroller needs access to a lot of RAM, the stored information has some form of structure where it can be seen as records, and where the program need not play with direct accesses but can instead implement get_record() and put_record() functions. This would directly remove the need for MOVX instructions, and allow a serial interface to be used without any hw complexity and with a very clean sw implementation. And SPI-connected FRAM is rather fast too.


List of 26 messages in thread
TopicAuthorDate
Need more Internal RAM            01/01/70 00:00      
   Yes, but they handle it the same as external RAM            01/01/70 00:00      
   Look here            01/01/70 00:00      
      Ok            01/01/70 00:00      
   complicated and complicated            01/01/70 00:00      
   why?            01/01/70 00:00      
   It's Not Really So Complicated--And....            01/01/70 00:00      
      someone recently posted a link to a 805x with 64kB of RAM            01/01/70 00:00      
      Proper methodology can't really bound the memory requirement            01/01/70 00:00      
      That's My Point            01/01/70 00:00      
   RAM expansion need not be complicated!            01/01/70 00:00      
      MOVX problem            01/01/70 00:00      
         No            01/01/70 00:00      
            unless you have external glue logic            01/01/70 00:00      
               Yes            01/01/70 00:00      
         "bible" time!            01/01/70 00:00      
      There are much larger SPI memories            01/01/70 00:00      
   Look at Wiz chip            01/01/70 00:00      
      Link?            01/01/70 00:00      
         links            01/01/70 00:00      
            Overkill?            01/01/70 00:00      
               and expensive?            01/01/70 00:00      
                  When at electronics store            01/01/70 00:00      
                     Which one?            01/01/70 00:00      
                     How does that compare with ordering from outside?            01/01/70 00:00      
                        I've always had to do that!            01/01/70 00:00      

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