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???
09/28/05 14:18
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#101666 - external vs internal XRAM
Responding to: ???'s previous message
Jon Ledbetter said:
[...] seems the ones that I've worked with, still access XRAM the same way, whether it's on the chip or not. Does there need to be a defined difference or just a mention that it could be included internally within some chips?


The differences are, for example:

- some of the faster derivatives are able to insert waitstates while accessing the external XRAM(XROM); of course they don't do that while accessing the internal XRAM

- using MOVX @Rn on RD2's (and maybe others) accesses only the bottom 256 bytes of internal XRAM, while with external XRAM it can access any address, within a page with high byte of address given by P2 (that's what Andy called PDATA)


Jan Waclawek


List of 40 messages in thread
TopicAuthorDate
glossary            01/01/70 00:00      
   Dunno, but...            01/01/70 00:00      
   glossary            01/01/70 00:00      
      "external"            01/01/70 00:00      
         explain            01/01/70 00:00      
      indirect?            01/01/70 00:00      
         Flash            01/01/70 00:00      
      XRAM            01/01/70 00:00      
         X?            01/01/70 00:00      
            XRAM            01/01/70 00:00      
               MOVX is the key            01/01/70 00:00      
                  access            01/01/70 00:00      
                     Sort of            01/01/70 00:00      
                        wikish            01/01/70 00:00      
                        memory types and datatypes            01/01/70 00:00      
                           precise            01/01/70 00:00      
                              maybe like this            01/01/70 00:00      
                                 XDATA            01/01/70 00:00      
                                    re: XDATA            01/01/70 00:00      
                                       update            01/01/70 00:00      
                                          why? does anyone ever look there            01/01/70 00:00      
                                             We don't understand each other            01/01/70 00:00      
                                                My understanding of the wiki was that it            01/01/70 00:00      
                                                   wicked            01/01/70 00:00      
                                                      re chip directories            01/01/70 00:00      
                                                Hang on            01/01/70 00:00      
                                                   sorry            01/01/70 00:00      
                                                      Nope            01/01/70 00:00      
                                                   Congrats Steve.            01/01/70 00:00      
                     stack =? IDATA            01/01/70 00:00      
                  PDATA???            01/01/70 00:00      
                     PDATA            01/01/70 00:00      
         That's the crux            01/01/70 00:00      
            internal external            01/01/70 00:00      
               Is there is difference in...            01/01/70 00:00      
                  external vs internal XRAM            01/01/70 00:00      
                     or other sfr            01/01/70 00:00      
            ERAM            01/01/70 00:00      
   Wiki Wiki            01/01/70 00:00      
      glossary on wiki            01/01/70 00:00      

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