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???
06/05/06 19:21
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 		 #117776 - returns 0x00
Responding to: ???'s previous message
Jan,

I have no way of testing the external memory access since I don't have any memory chips or a latch at the moment.

Hmmm (I have a bad case of the flu so please excuse me if this is totally wrong), could I just connect the P0 pins to P2 thus allowing me to try and read external memory always returning the high byte of the memory address?

List of 67 messages in thread
TopicAuthorDate
DS89C420 internal SRAM Access question            01/01/70 00:00      
   Timed access            01/01/70 00:00      
      Re: Timed access            01/01/70 00:00      
         Lacking ?            01/01/70 00:00      
            Re: Lacking            01/01/70 00:00      
   dunno            01/01/70 00:00      
      Re: dunno            01/01/70 00:00      
         lots of features to track            01/01/70 00:00      
   Example Code            01/01/70 00:00      
      Dallas SRAM Access            01/01/70 00:00      
   Update / Further Puzzle            01/01/70 00:00      
      False Alarm            01/01/70 00:00      
         A bug, maybe?            01/01/70 00:00      
            Isn't that CPU EOL (or not for new des?)            01/01/70 00:00      
               Yes, it's been replaced but he has it.            01/01/70 00:00      
                  Not Quite EOL but thats next ...            01/01/70 00:00      
                     Could be a disappointment            01/01/70 00:00      
                  how are you going to know if the problem            01/01/70 00:00      
                  Damned with faint praise!            01/01/70 00:00      
                     Clearly it's not for production            01/01/70 00:00      
                        Is there a difference between IAP & ISP?            01/01/70 00:00      
                           what I understand is            01/01/70 00:00      
                              DS89C4x0 IAP/ISP explained            01/01/70 00:00      
                           Final Update            01/01/70 00:00      
                              Try this            01/01/70 00:00      
                                 Re: Try this            01/01/70 00:00      
                                    It may be time for a different specimen            01/01/70 00:00      
                                       Re: new specimen            01/01/70 00:00      
                                          huh?            01/01/70 00:00      
                                             not enough benefit in replacing            01/01/70 00:00      
                                          I've been at this a LONG time ...            01/01/70 00:00      
                                    what does it return            01/01/70 00:00      
                                       returns 0x00            01/01/70 00:00      
                                          probably, but why?            01/01/70 00:00      
                                          I doubt you have to connect 'em            01/01/70 00:00      
                                              do not know what ISTR is            01/01/70 00:00      
                                                what it means            01/01/70 00:00      
                                                me either            01/01/70 00:00      
                                                   before you "move on"            01/01/70 00:00      
                                          oscillscope             01/01/70 00:00      
                                             it's not clear how a 'scope will help            01/01/70 00:00      
                                                Well a 'scope would ...            01/01/70 00:00      
                                                   exactly ... so why not have another look            01/01/70 00:00      
                                                      code?            01/01/70 00:00      
                                                         What about SFR definitions?            01/01/70 00:00      
                                                            SFR Def            01/01/70 00:00      
                                                            SFR was defined            01/01/70 00:00      
                                                               bad idea            01/01/70 00:00      
                                                                  Yep, it leads to confusion!            01/01/70 00:00      
                                    but...            01/01/70 00:00      
                                       confusion            01/01/70 00:00      
                                          That was what I wondered, too.            01/01/70 00:00      
                                             So ... What about it?            01/01/70 00:00      
                                             Clear a few things up            01/01/70 00:00      
                        wrong way around            01/01/70 00:00      
                     Most the time..            01/01/70 00:00      
                        That's undoubtedly the case.            01/01/70 00:00      
   Matthew, I am curious about something            01/01/70 00:00      
      Answer as best I can            01/01/70 00:00      
         It's still not clear ...            01/01/70 00:00      
            hmmm try some more            01/01/70 00:00      
               I don't think I'd try that ...            01/01/70 00:00      
                  Re:            01/01/70 00:00      
                     It's not rude ...            01/01/70 00:00      
                        Now ... here's what I did ...            01/01/70 00:00      
               test.asm once more            01/01/70 00:00      
                  Some more questions            01/01/70 00:00      

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