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???
09/26/06 13:38
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 		 #125066 - Go for the "V"!
Responding to: ???'s previous message
Erik Malund said:
do the right thing, migrate to the current P89V51Rx2. then there are no issues re 'kicking it in ISP'.


Yes!

The "V" chip works this way: upon reset, the bootloader is run no matter what; it waits some time looking at Rx and if it won't change during this time, it restarts itself running the user code.
No more fiddling around /PSEN and P2x when you want to , no more "lost bootvector" issue...

Erik Malund said:
The only 'trap' using the V chips is that if you screw up and specify a C chip in FM when programming the V it may go into SoftICE mode.


There is a remedy for this so it is not fatal (however, the "remedy" is a pain so better avoid it)...

However, there are more "traps", for example if the application is such that there is no guarantee for no character arriving at Rx during reset, the bootloader might get activated errorneously. Also, certain applications might not tolerate the delay in starting the user code.
Fortunately, the bootloader is in FLASH and can be modified. Unfortunately, Philips does not provide enough information to do it. Fortunately, there appears to be a way... :-)

JW

List of 49 messages in thread
TopicAuthorDate
Need Help: Problem with ISP on P89C51RC2HBA            01/01/70 00:00      
   application?            01/01/70 00:00      
      only if he misspelled            01/01/70 00:00      
         my bad            01/01/70 00:00      
            Still            01/01/70 00:00      
      application?            01/01/70 00:00      
         FIRST, second and third            01/01/70 00:00      
         I'm afraid...            01/01/70 00:00      
            It's in the errata            01/01/70 00:00      
               it's a stupid practice...            01/01/70 00:00      
                  not from their perspective            01/01/70 00:00      
                     we discussed this already many times            01/01/70 00:00      
                     Why not make them OTP's, then?            01/01/70 00:00      
                        they are if you follow the instructions            01/01/70 00:00      
                           compromise            01/01/70 00:00      
                              just exactly HOW do you "push" on the mfg?            01/01/70 00:00      
                                 push on the mfg            01/01/70 00:00      
                                    only works when you spend MONEY            01/01/70 00:00      
                     An Old chip will known Devil ?            01/01/70 00:00      
               bootvector lost already            01/01/70 00:00      
                  there IS code in the chip            01/01/70 00:00      
                     how do you mean?            01/01/70 00:00      
                        Rx+            01/01/70 00:00      
               I found an errata            01/01/70 00:00      
            I'm afraid...            01/01/70 00:00      
               drop me an e-mail via my profile            01/01/70 00:00      
            I'm afraid...            01/01/70 00:00      
   first, second third            01/01/70 00:00      
      Must be an Atmel's micro...            01/01/70 00:00      
         naah, that is NOT the issue            01/01/70 00:00      
      first, second third            01/01/70 00:00      
      first, second third: second            01/01/70 00:00      
         boot vector lost            01/01/70 00:00      
   Try this            01/01/70 00:00      
      Try this            01/01/70 00:00      
         FM            01/01/70 00:00      
            FM            01/01/70 00:00      
               FM can not restore a lost bootvector            01/01/70 00:00      
               it's too late            01/01/70 00:00      
                  it's too late            01/01/70 00:00      
                     do not            01/01/70 00:00      
                        Oh...            01/01/70 00:00      
                           no chip 'requires' reset IC but ALL flash based ..            01/01/70 00:00      
                           the trouble with RC resets...            01/01/70 00:00      
                              How, exactly, did you arrive at this notion?            01/01/70 00:00      
                                 experience...            01/01/70 00:00      
                                 the reason            01/01/70 00:00      
                        Go for the "V"!            01/01/70 00:00      
                           while these are valid concerns            01/01/70 00:00      

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