Email: Password: Remember Me | Create Account (Free)

Back to Subject List

Old thread has been locked -- no new posts accepted in this thread
???
09/22/06 07:16
Read: times


 		 #124851 - I'm afraid...
Responding to: ???'s previous message
Vigneshwara Baliga said:
There should not be any application running as this is a new chip, I just bought (only one)


Vigneshwara,

When you reset* the '51Rx2, if it would be "untouched" new, it would go into the loop waiting for negative pulses on the Rx pin (= the 'U' from Rx for autobauting). It does not transmit spontaneously. If it does, it means, that there IS already something "burned" inside, and the status byte and/or bootvector is altered.

In other words, if you buy a chip, put it into a basic circuit (VCC, reset, crystal, MAX232-like) and it starts to transmit something spontaneously, sorry, that was NOT a new chip, and the previoush history of it is unknown - very likely it already has altered boot vector (intentionally or not).

Vigneshwara Baliga said:
and I don’t have a parallel programmer :-(
How do I solve the Bootvector loss problem ?

The BEST way is to get a parallel programmer, or at least an access to it. Maybe you could try to locate somebody or some company who have it and ask them to reprogram the chip (maybe for some small fee). You might also try to ask at the place where you bought it.

Bill Houghton hinted on an alternative method about a year ago - basically, the bootloader can be run from external memory. I wrote a "bootvector restorer" based on this fact, to be run from external memory (that's why I asked if you have such a board); but that was tried on P89C51RD2Hxx and I am not completely sure (althought quite confident) if it would work on the '51RC2Hxx and I have none to try - but if you are interested and willing to experiment at your own risk, I can send it to you - drop me an e-mail via my 8052.com profile.


Jan Waclawek

-------
* I don't know the exact effect of RC reset on this particular chip but some '51s tend to go completely crazy if not properly resetted so I cannot conclude definitively on your chip until you get a decent reset for it


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      

Back to Subject List